00:01 Nobel laurates in physics and chemistry
00:05 laurates in economic Sciences your
00:08 excellencies members of The Academy
00:12 gentlemen on behalf of the royal Swedish
00:14 Academy of Sciences I wish you all
00:16 welcome to the 2023 Nobel lectures in
00:20 physics and chemistry and the lecture of
00:23 the various Rick Bank prize in economic
00:25 Sciences in memory of Alfred
00:27 Nobel Alfred Nobel was an inventor an
00:31 entrepreneur a scientist and a
00:34 businessman as well as an author writing
00:37 poetry and drama and in N 1895 he
00:42 devoted his fortune to five
00:43 International prices reflecting his own
00:46 International experiences and
00:49 activities and the first Nobel Prize was
00:52 awarded in 19001 that is over 120 years
00:56 ago and the Nobel Prize in physics is
00:59 awarded for discoveries and inventions
01:02 and in chemistry for discoveries and
01:04 improvements that have conferred the
01:07 greatest benefit to
01:09 humankind and the s six Bank price in
01:11 economic Sciences or in memory of Alfa
01:14 Nobel was instituted in
01:18 1968 and we are pleased to see you all
01:20 here to listen to the Nobel Prize and
01:25 lectures the past year
01:28 2023 has been a dramatic year with many
01:31 crisis ongoing at the same time we have
01:35 a climate crisis with the warming of the
01:37 climate an energy crisis and we are
01:41 fighting against inflation that poses a
01:45 economy we have a war ongoing since 2022
01:49 in our neighborhood in Europe and the
01:52 war that started recently in Middle East
01:55 both leading to humanitarian
01:58 catastrophes also we are still
02:00 recovering from the covid-19 pandemic
02:03 and even though that we have seen a
02:05 significant decrease of the number of
02:08 severe cases with covid-19 the infection
02:13 again however we are in a best situation
02:18 2020 as we have vaccines that have
02:21 helped us to reduce disease development
02:24 mortality and this fast impressive
02:27 vaccine development was only possible
02:30 due to scientific discoveries made many
02:33 years ago on which new knowledge could
02:37 built and the current turbulent world
02:40 underlines the importance of enabling
02:43 new discoveries inventions and
02:46 improvements that will benefit
02:49 humankind and also stresses that
02:53 Global scientific discoveries are driven
02:56 by curiosity and deep insights to
02:59 generate new knowledge and it's
03:01 impossible to determine what will be
03:06 future moreover we don't know what the
03:09 next challenges to humankind will be
03:12 therefore we need to have bottom up and
03:14 Broad approaches and the roads to
03:17 Discovery can be long and winding but
03:20 can lead to unanticipated surprises and
03:23 openings that were not
03:25 considered and we have seen
03:27 groundbreaking discoveries during the
03:30 and we will now have the privilege and
03:32 honor to listen to exception researchers
03:35 and laurates who have increased our
03:38 fundamentally and broaden our views in
03:41 three different areas of
03:44 research the laurates of this year's
03:46 Nobel Prize in physics have given
03:48 Humanity new tools to explore the world
03:51 of electrons inside atoms and
03:54 molecules and they managed to produce
03:57 light pulses that are so short that they
04:00 are measured in atos seconds and these
04:03 short pulses of light can be used to
04:05 measure the rapid processes in which
04:08 electrons move and change
04:11 energy previously not possible to follow
04:14 and at a second puzles can also be used
04:17 to identify different molecules for
04:22 Diagnostics in the Nobel prizing
04:24 chemistry the Laurus had discovered and
04:27 developed Quantum dots and these Nara
04:30 particles are so small that their
04:32 properties are determined by Quantum
04:35 phenomena and they have many fascinating
04:38 and unusual properties such as having
04:41 different colors depending on their size
04:44 in Quantum dots are now being used in
04:46 many applications such as television in
04:49 lead lamps and also to guide surgeons
04:52 when they are performing surgeries such
04:55 tumors and the laureat in this year's
04:58 price in economic Sciences
05:00 have has uncovered key drivers of gender
05:02 differences in the labor market and the
05:05 laurat provided the first comprehensive
05:08 account of women's earnings and labor
05:12 participation and demonstrated how and
05:15 unraveled why gender differences in
05:17 earnings and employment rates have
05:19 changed over time and Main sources for
05:22 the remaining gender
05:24 gap all these Achievements not only
05:27 bring new knowledge and deeper
05:30 but also allow us to improve our
05:32 Societies in multiple ways and to take
05:37 decisions and we will now listen to
05:39 these priz lectures by these exceptional
05:41 researchers on Whose shoulders present
05:44 and future humans can stand and new
05:47 Giants and research will surely
05:49 arise so once again most welcome and my
05:53 warmest congratulations to the
05:56 laurates and I now invite my colleague
05:59 in the Academy of Sciences Professor Eva
06:01 olon who is the chair of the Nobel
06:03 committee for physics to introduce the
06:18 physics honored Nobel
06:23 excellencies distinguished colleagues
06:28 gentlemen a warm welcome to the Nobel
06:33 physics and the prize in Nobel physic
06:38 the Nobel Prize in physics this year is
06:43 physics and atet in
06:47 physics is about very very very small
06:54 scales so small that the number of at
06:58 seconds in one second is the same number
07:02 as a second since our universe was
07:07 born even though the time scale is so
07:11 small what is taking place on that small
07:15 time scale is affecting our daily life
07:19 because it determines properties on in
07:24 aspects AR second physics reveals the
07:29 life or the electrons and their
07:32 Dynamics and through the knowledge of
07:35 what is happening on that small time
07:37 scale and with the electrons we get the
07:42 ability and the knowledge to make new
07:49 materials we also can design Electronics
07:55 Concepts and we can develop methods for
08:00 are most importance for human
08:05 mankind and our lores they discovered
08:08 that it was possible to generate these
08:14 pulses they develop methods to measure
08:18 the duration of the light
08:21 pulses and they also develop methods for
08:24 generating pulse trains and also individ
08:29 ual isolated light pulses of the Year
08:36 duration and our Nobel laurates in
08:42 physics we will see
08:45 here and I get some help to switch to
08:58 slide and while we're figuring out how
09:00 to go there so uh our here they are yes
09:07 Nobel laurates in physics this year is
09:10 Pierre agustini fence K and an
09:16 ler and it is my pleasure now to
09:19 introduce our first speaker and this is
09:22 uh an ler so please well help join me in
09:55 so good morning um it's a pleasure to be
09:58 here and let let me start by uh thanking
10:01 the Royal Swedish Academy of Sciences
10:04 and the Nobel foundation for this prize
10:07 and for the pleasure the privilege to uh
10:12 lecture so I will uh tell you about how
10:15 we arrived to this atan PES this is a um
10:23 atan Science with the first
10:26 years uh progress in techn ology and in
10:31 understanding measurement of atan pulses
10:34 and then opening to research fields and
10:38 applications and I will go through the
10:41 first two parts and leave part three to
10:44 my colorat measurement of atan pulses I
10:48 will in the end just uh say a few words
10:55 applications nothing would have happened
10:58 without the invent mention of the laser
11:00 in 1960 by Theodore minman and the Nobel
11:05 Prize in physics was given to the
11:07 background for laser in 1964 to towns
11:13 proov and you have here a picture of one
11:16 of the first lasers a ruby
11:19 Laser Now what we are going to use in
11:23 research uh the properties of the laser
11:26 are first the possibility to generate
11:29 short laser pulses and especially the
11:32 possibility to by focusing these pulses
11:36 to achieve a very high
11:39 intensity so the invention of the laser
11:43 led to new research fields and the first
11:46 one is nonlinear Optics this is a
11:49 picture of an an experiment performed by
11:53 Peter Franken in 1961 immediately after
11:57 the invention of the laser and uh you
12:02 laser which is focused by a lens into a
12:05 material and experiment will look very
12:08 much the same and then we the radiation
12:14 prism and detected by a
12:19 process uh an atom absorb two photons
12:22 it's a nonlinear Optical process and
12:25 emit a photon at frequency 2 Omega this
12:29 is second harmonic generation the first
12:32 nonlinear Optical processes that was
12:37 discovered now another research field
12:40 that started after the invention of the
12:42 laser is atoms in strong fields or
12:45 multiphoton processes that were
12:47 predicted already in 1934 by Maria goer
12:53 Mayer and in the multi Photon processes
12:57 an atom absorb several photons
13:00 simultaneously it can be
13:10 agustini discovered the process of above
13:13 threshold ionization where an atom is
13:16 ionized by absorbing more Photon that is
13:21 necessary for ionization and this is
13:24 detected by observing electrons and one
13:30 Peaks now an atom can also be multiply
13:34 ionized and this was actually my thesis
13:37 work at the beginning of the
13:43 time the question arised is it possible
13:46 to produce excited atoms or excited ions
13:51 that then would uh Decay by emitting
13:55 fluorescence light so we set up an
13:58 experiment expent this was in France at
14:01 the commissar energy Atomic we set up an
14:05 experiment to observe this fluoresence
14:07 light fluoresence light is emitted in
14:10 all Direction so we had actually two
14:15 detection one along the direction of the
14:19 propagation axis of the laser with a
14:22 grating and a detector and one
14:27 it and this is the laser that was used
14:30 at that time a nudum yag
14:33 laser one micrometer wavelength and P
14:36 duration was 40 p a second you have an
14:39 oscillator here and two
14:42 amplifiers and this is a picture of uh
14:45 the experiment set up uh you have a
14:49 laser is coming from the right you have
14:52 a lens focusing the laser into a chamber
14:55 and the radiation is detected along the
14:58 propagation access with a grating and a
15:01 detector and perpendicular to
15:04 it the intensity reach in the medium so
15:09 here we have also a pulse G jet
15:13 delivering some gas of atoms so the
15:16 intensity in the medium reach several
15:19 times 10 to the 13 watts per square cm
15:24 High what did we see well we
15:29 never see anything we never saw anything
15:32 perpendicular to the detection axis so
15:34 I'm not going to discuss that
15:37 anymore and we didn't see much
15:40 fluorescence what we saw was very high
15:44 order harmonics of the laser field and
15:47 this is one of the first Spectra
15:50 obtained in argon gas and what you see
15:53 here are harmonics 13 15 up to 31 first
15:59 harmonic of the laser field so when it
16:02 says 13 here that means that the
16:05 frequency is equal to 13 times the laser
16:09 frequency now if we plot the intensity
16:13 distribution of these high harmonics we
16:16 get the typical Behavior with the
16:19 decrease a plateau Behavior where all
16:22 the harmonics have the same
16:24 intensity and this is ending with a cut
16:28 off and this was very unexpected first
16:32 it was not expected to see so many high
16:36 harmonics then it was not expected to
16:39 have this Plateau Behavior one thought
16:42 that the it would be more and more
16:44 difficult to generate high order
16:47 harmonics this was based on some kind of
16:50 perturbation Theory thinking at the time
16:53 that based on an expansion of uh the
16:56 polarization induced in the medium uh in
17:00 in powers of the electric field we for
17:05 this expansion to be valid one has to
17:08 assume that the first order is uh is
17:12 much larger than the third and much
17:14 larger than the fifth and this was not
17:18 case you can notice that I'm only
17:23 orders uh of the laser and this is due
17:27 to a symmetry prop y of the medium it
17:29 has the inversion symmetry so the even
17:32 order harmonics are actually
17:35 killed now if you go from
17:39 a a frequency of the laser light which
17:42 is in the infrared region and you
17:45 multiply this frequency by let's say
17:48 33 you end up in the extreme ultraviolet
17:53 region of the spectrum see it's below
17:55 x-rays but above ultraviolet that light
17:59 so this light is invisible and it does
18:02 not propagate in air so we have to
18:05 evacuate now let's make a little bit
18:09 analogy with music here um when we uh
18:14 think about harmonics usually think
18:18 music uh what we do is actually very
18:21 similar to what happens when the bow of
18:24 a violin hits a string of the violin it
18:28 produce not only a single tone but also
18:34 overtones and this is what actually make
18:36 the the clang the timber of music
18:40 instrument is how many of these
18:44 have in our experiment we produce not
18:48 harmonics of sound but harmonics of
18:51 light and the the violin is the gas of
18:54 atoms and the bow of the violin is the
19:02 process uh requires to
19:05 uh it it at the border of two Fields
19:08 Atomic physics and nonlinear Optics
19:11 Atomic physics is the description of the
19:14 response of an atom to the laser field
19:17 and this is uh we are in the quantum
19:19 word this is described by a schinger
19:22 equation that you have here where you
19:25 have here the atomic potential and the
19:28 laser atom interaction in this uh
19:31 problem we can describe the laser field
19:34 classically and we use the dipole
19:39 approximation now the second aspect is
19:42 uh nonlinear Optics the response of many
19:46 radiation uh it's not enough that each
19:49 atoms generate these high harmonics you
19:52 also need to have efficient harmonic
19:55 generation to have the emission from all
19:58 of the atoms in the medium in phase at
20:03 coherently and this is described by a
20:05 Maxell equations of
20:07 electromagnetism which can simplify to a
20:10 wave equation as what is written here e
20:14 here is the generated field in the
20:16 medium and P is the polarization in the
20:19 medium induced by the laser
20:26 attempt yeah let me say one more thing
20:29 again analogy to music this many atom
20:32 response you can think of a gigantic
20:35 Orchestra all of the musician in this
20:38 Orchestra need to play with the same
20:40 pace and the number of atoms in this
20:43 Orchestra is trillions of atom many more
20:47 than the number of people on Earth just
20:49 to give you a little bit an order of
20:51 magnitude now the first attempt to
20:56 processes was to Simply solve these two
20:59 equations which I just wrote and this
21:02 calculation uh of this single atom
21:05 response solving numerically the shingar
21:08 equation and you see that the agreement
21:11 between theory is experiment is quite
21:14 good in itself it's a bit surprising
21:17 because at that time we thought that
21:20 many atom response would be very
21:22 different for the different harmonic
21:24 order it would be more and more
21:27 difficult to face much uh this the
21:30 process so it was really necessary to
21:33 also solve the second equation the wave
21:36 equation and this is what was done here
21:39 you see that uh we obtain rather good
21:43 agreement again with the experimental
21:46 behavior and we can reproduce this
21:49 plateau and cut off Behavior so we can
21:53 simulate the experiment but we don't uh
21:58 really understand the physics behind
22:01 approximately at the same time was asked
22:04 the question could it be that uh these
22:08 high order harmonics form in the time
22:11 domain a series a train of atan pulses
22:15 and the idea is the following consider
22:19 let's say three harmonics 17 19 and
22:24 21 and assume that these Harmon
22:29 are all in phase at a certain time they
22:32 are phas locked if they are in Phase
22:36 synchronized at a certain time they will
22:38 be again in Phase after half the laser
22:42 cycle so now if you sum these three
22:46 waves you see that uh we get
22:50 constructive interference when they are
22:53 in phase and destructive interference
22:55 where they are not in phase we can
22:58 confined the light into short pulses and
23:02 if we plot the intensity corresponding
23:04 to this electric field you get a train
23:07 of at a second PES if you sum not only
23:11 three harmonics but let's say 10
23:13 harmonics and you assume they are phas
23:16 locked you obtain a train of very short
23:19 light Parts why is it
23:22 interesting because the U evolution of
23:26 uh the p of lasers had come to a stop
23:31 this is the evolution of the part
23:34 duration of D lasers decreasing from
23:37 Picos seconds down to a few fto seconds
23:41 and couple of years later titanian Safa
23:45 laser would also arrive at the stop of
23:49 about two F second and the reason for
23:52 this stop is uh that we are talking
23:58 and and to talk about a light pulse you
24:01 need to have at least one Optical period
24:03 in this pulse and uh the optical period
24:07 of for example a titanian Safa laser is
24:10 2.6 F Toc so in order to decrease the
24:14 PSE duration you need to decrease the
24:17 optical period which means to go to
24:20 frequencies now the second condition to
24:23 get short pulses is that you need a
24:26 broad bandwidth this is just an
24:28 expression of Heisenberg Principle to
24:32 get a short time you need a broad
24:35 bandwidth and uh this high order
24:37 harmonics provided both higher
24:40 frequencies in the extreme ultraviolet
24:43 and the Broadband with this Plateau
24:47 Behavior so this was a very exciting
24:50 question so now I'm coming to the second
24:54 part of this talk which is progress in
24:57 understanding in and progress in
24:59 technology and I would like to start by
25:03 technology at the beginning of the '90s
25:05 there was a huge progress in Laser
25:08 Technology first with the chpo
25:11 amplification which led to a Nobel price
25:14 to gir moru and Dona streetland in
25:18 2018 there was the discovery of a new
25:20 material tianan sappire by Peter Molton
25:24 and then a new way to uh to generate
25:28 short pulses in the laser oscillator
25:31 which was carens mod
25:33 loocking and here you have three Swedish
25:37 scientists Sun as fber and person CL and
25:40 vstrom that look at this new Laser
25:45 Technology and they decide to really
25:48 invest into this new Laser Technology
25:51 this was very risky because it was not
25:54 clear that it would work but they really
25:57 uh invest into this technology and uh
26:00 build the uh high power laser facility
26:03 in Lund with terawat titanian Safa laser
26:07 this was really the perfect laser to
26:11 study high order harmonic generation
26:13 with a short duration of the order of
26:16 100 F second and at that time a high
26:20 repetition rate 10 laser shots per
26:26 Hertz in parallel to that there was also
26:31 instrumentation uh in Sak we build a a
26:36 dedicated instrument to study hod
26:38 harmonic generation which you see here
26:41 and uh these instruments include gas jet
26:44 Optics to analyze the radiation and a
26:47 detector and here you have myself much
26:51 younger but together with Philip Balu
26:54 and Pascal saler my first uh uh PhD
26:58 students uh we are here in the audience
27:02 today and uh this is also the time uh
27:07 computers uh came into the laboratory
27:10 the first experiment that I mentioned we
27:12 were using a printer to record the
27:15 signal Now personal computers started to
27:18 uh really come into the lab and we could
27:21 uh thanks to these computers really take
27:24 data in a very completely different way
27:28 so we performed the so this led to a
27:33 very nice experiments combining this
27:35 dedicated instrumentation and this new
27:38 laser system titanian safire and I show
27:41 here one of the first Spectrum obtaining
27:44 neon using this laser by a group in
27:49 Stanford and there you see a beautiful
27:51 harmonic Spectrum with a very large
27:55 Plateau here this decre at the the
27:57 beginning is simply due to the decrease
28:00 in efficiency of the greting and you
28:02 have the cut off in in this region so
28:06 you see that we go to the 111
28:10 harmonic and in Lund uh together with
28:13 the uh collaboration Lund and S uh we
28:17 could not only take harmonic Spectra but
28:20 really study uh the uh these harmonics
28:24 as a function of different parameters
28:27 for example here as a function of the
28:33 now approximately at the same time came
28:36 really a breakthrough in the theoretical
28:39 understanding of of this procept with
28:41 the three-step model so I would like to
28:44 say here that this price is given to the
28:48 uh experimental method in atos science
28:52 but the theorists have played a very
28:54 very big role in uh in at to in science
28:58 and in particular in in uh uh the
29:02 understanding and the this three-step
29:04 model and this was shown pro at the same
29:08 time by Ken kander and Ken schaer by
29:11 Paul Corum in Canada and uh Mach
29:15 lanstein and co-workers here Misha
29:18 Ivanov uh presented a Quantum
29:20 formulation of the three-step model
29:22 called the strong field approximation
29:25 which was going to have a very strong
29:27 impact in the field so this three-step
29:31 model is presented here what happens is
29:34 that you have an atom in a strong laser
29:37 field and this laser field is really
29:39 strong it distorts the atomic potential
29:43 it's it's Bend this potential and here
29:46 you have a barrier so an electron in the
29:49 ground state this is quantum
29:52 mechanics there is a certain probability
29:54 for the electrons to Tunnel through this
29:58 then the electrons is driven Away by the
30:00 laser field the laser field changes sign
30:04 the electron is push back towards the
30:06 atom and then there is a certain
30:08 probability of Rec combination in this
30:12 excursion the electron has uh gained
30:15 some kinetic energy and the uh excess
30:19 energy is uh is emitted in in the form
30:23 of a high energy Photon and this process
30:26 is repeated every half laser cycle on
30:29 one side and the other sides and again
30:32 and again leading to emission of light
30:36 uh every half cycle of the
30:40 laser now what about add to Second
30:43 pulses uh I just remind you that we have
30:47 uh discussed that if we had the face
30:50 locked harmonics in the time domain we
30:53 would have one pulse per High cycle so
30:56 what was this a new theoretical
30:59 understanding telling us and here is the
31:02 bad surprise this was the result of the
31:08 everywhere no one pulse per cycle so no
31:12 face locked harmonic so the atan idea at
31:15 that time was uh quite controversial and
31:19 not so clear how can we understand this
31:22 uh multiple PSE emission actually we can
31:25 understand very simply using this uh
31:29 three-step model and looking at the
31:31 possible electron trajectory this is
31:34 just a a very simple uh picture of these
31:37 trajectories electron going out and
31:40 coming back uh I put in colors the
31:45 energy that the electron have when they
31:48 return uh so you have higher and higher
31:51 energy depending on when the electron is
31:54 born but there are also traj rectories
31:58 which takes longer time and leads to
32:01 similar type of energy so when you look
32:04 at the possible trajectory you find that
32:07 trajectory and long trajectory leading
32:10 to the same kinetic energy and this
32:12 complex picture lead to this complex
32:17 domain now we could uh actually verifi
32:21 the existence of these trajectories in
32:24 the laboratory this is an experiment
32:26 performing Lon 98 and you have some of
32:30 the participants here metor who in the
32:33 audience Ted Hench Marco bini and
32:36 others and uh what we did in this
32:39 experiment was to look at the coherence
32:42 of this High harmonic is it coherence
32:44 light and to do that we
32:47 duplicate uh the harmonic sources and we
32:51 look at whether this light interfere in
32:54 the far field if this is coherent we
32:56 should have interferences and indeed you
32:59 see here on the 15th harmonic that there
33:02 are beautiful interference
33:04 fringes what you can also see in this
33:07 picture is that there are now two
33:09 contributions there is collimated
33:13 Divergent uh contribution which we could
33:16 identify to the contribution from the
33:18 short trajectory and from the long
33:21 trajectory now we could also delay one
33:25 of the source uh relative to the other
33:28 and look at what happens to the
33:30 interferent fringes and you see that in
33:33 this case the interference are still
33:36 present for the collimated radiation
33:39 while they are gone for the more
33:41 Divergent contribution which shows
33:43 different properties of these two
33:46 contribution short and long
33:49 trajectory what happens to the other
33:52 side strong field nonlinear Optics the
33:55 response of many atoms there's
33:59 also progress in in this part as well so
34:03 to achieve fast mching here we need the
34:06 phase of the uh part which is
34:10 generated to be in equal to the phase of
34:14 the polarization induced in the medium
34:17 so we need these two wave vectors here
34:22 equal and this difference in wave Vector
34:26 the depends on the dispersion in the
34:29 partially ionized medium depends on the
34:31 laser focusing but it also depends and
34:34 that's the important thing on the
34:36 electron trajectory whether it's short
34:39 or long and this gave us the idea or
34:42 maybe in some condition only one of this
34:46 trajectory can survive only one of this
34:49 trajectory get face much and indeed this
34:52 is what we got uh this is uh in FL line
34:57 you have the single atom response where
34:59 in blue you have the temporary structure
35:03 of the uh total atoc pulse train so we
35:08 recover one atosan pulse per laser High
35:11 cycle and pH locked
35:14 harmonics so at this point um we think
35:18 that oh maybe we have at pares but what
35:21 is very important is to measure at to
35:25 passes before I to the conclusion of
35:27 this talk let me point out that at the
35:30 end of the '90s there is really a lot of
35:33 progress both in laser and in high order
35:36 Harmonic Technology and let me just
35:39 flash some of this progress first now we
35:43 can uh generate laser pses that are very
35:46 short few cycles and then the important
35:50 of the carrier envelope phase is uh is
35:55 uh pointed out and this the carer
35:57 envelope phas is the the phase offset
36:00 between the electric field and the
36:02 envelope and this was going to be very
36:04 important for the generation of single
36:08 pulses then you have a no novel medium
36:12 geometries like cell or um capillaries
36:17 you have also New Media that are being
36:22 molecules you have a a push toward
36:26 higher pH on energy using short laser
36:29 parts and especially long wavelength
36:31 lasers and you have also pushed toward
36:34 higher pulse energy in the microle range
36:37 using clever uh focusing
36:41 geometries so now I am going to uh jump
36:44 over this part three and I would like to
36:48 uh finish this presentation by um just
36:51 giving you two example of application
36:54 very different example one is very very
36:57 fundamental this is about electron
36:59 Dynamics and one is much more applied so
37:03 electron Dynamics uh I think that's
37:06 exciting thing about uh atan pars is we
37:09 can now follow the Dynamics of electrons
37:13 in matter and here I take one example
37:16 which is very simple it's
37:18 photoionization a process that would
37:20 understood theoretically by Albert
37:23 Einstein in 1905 and he actually got the
37:26 Nobel price just for the discovery of
37:29 the low of the photoelectric effect so
37:32 what we can do and I'm going to talk
37:34 about photo ionization of atoms what we
37:38 can do thanks to atos PSE is we can now
37:42 answer question how long time it takes
37:45 for an electron to propagate in the
37:47 continum what are the wave Quantum
37:51 properties of the photo electrons and
37:54 I'm not going to uh explain how we do
37:57 these measurements I just want to try to
38:00 make you understand what we can do Again
38:03 by using an analogy with music in music
38:06 you keep the pace by the conductor is
38:10 keeping the pace or the metronome can be
38:14 used to keep the pace and the metronome
38:17 has a has a a a motion like this so this
38:21 is a wave motion both the conductor and
38:24 the metronome which is due to the
38:25 mechanical motion of the tip of the
38:28 metronome and this is exactly what we do
38:33 oscillations such as this one here and
38:36 we are going to compare the position of
38:39 the Maxima of this oscillation and this
38:43 oscillation here I'm talking about
38:45 photoionization of neon atoms in the two
38:48 a shell which I'm comparing to phonation
38:54 shell and what do we measure uh it's
38:57 always interesting to talk about time by
39:00 showing a clock in our measurements 1
39:03 hour on a clock is 1 half period of the
39:07 laser which is 1.3 F to second so uh 1
39:13 1,300 at to and what we can measure very
39:18 accurately is uh the position of of two
39:23 arrows on this clock uh which corresp
39:26 respond to the time it takes for the
39:28 electron to ionize from the 2 H shell
39:30 and from the 2p shell we don't know
39:33 where these two clocks are on this clock
39:36 but we can measure the difference in
39:39 time between these arrows and now I'm
39:43 showing some U results uh showing that
39:48 indeed we can uh measure this uh uh
39:51 relative time quite accurately within
39:54 tense of at a second
39:57 the second application I would like to
39:59 uh to mention is really going into a
40:02 completely different direction now very
40:04 applied and uh this is now belonging not
40:08 to the Research Laboratories anymore but
40:10 to Industry and this is an application
40:14 not so much about the temporary
40:15 structure of uh this High harmonics not
40:19 so much about acan path but about simply
40:22 an application of this uh uh radiation
40:26 which is in the extreme ultraviolet uh
40:28 rench and which is very Broad in in
40:32 frequency so now it harmonic generation
40:36 are being used to control
40:39 Wafers uh silicon Wafers uh which
40:43 contain uh integrated circuits and this
40:47 technique is used for the Next
40:48 Generation instruments that will control
40:52 this integrated C with very very small
40:56 of the order of 10 nanometer or below
40:59 and this control is made not only in 2D
41:02 but in 3D and what is really used here
41:06 is the fact that we have so many
41:08 frequencies and this is developed by an
41:11 industry asml in in Holland now to
41:15 conclude I would like to uh thank many
41:17 people all of my colleagues during all
41:20 of these years and I'm showing here uh
41:24 some uh group pictures not uh since
41:28 1987 just the last 15 years or so uh I
41:33 would like to also thank the um
41:36 organizations that uh have funded This
41:39 research the Swedish science Council
41:42 Swedish research Council and the
41:44 European research Council the valenberg
41:47 foundation and last but not least I
41:50 would like to thank my family cler an
41:54 Oscar and Victor thank you thank you for
42:37 so we're just going to fix the the uh
42:40 rug here to make sure that we don't trip
42:43 on it thank you very much and for uh
42:50 Expose and uh now we come to the next
42:53 step and um this is is now pier
42:59 agustini and Pier augustini is from the
43:04 University so please welcome um please
43:07 join me in welcoming Professor
43:26 uh good morning everyone and uh okay the
43:30 title of my talk is the generis Genesis
43:34 of an at P trade uh it has nothing to do
43:45 see um okay if some of you have never
43:55 before it's very short time it's uh a
44:00 billions of billions of second and uh so
44:07 one question one natural question that
44:11 could could arise is uh is this series
44:16 of you know from second to uh Nan
44:21 seconds and fto and aocs and ball
44:26 uh is infinite uh is it possible that to
44:33 to divide the type indefinitely like
44:36 that um from a physics point of view I
44:41 would say that that's doubtful because
44:46 first of all it takes more and more
44:49 energy to produce those short pules and
44:56 will hit the plank time and that's an
45:00 absolute limit uh we are still very far
45:04 from that time but it's probable that
45:08 okay the series is not infinite and you
45:12 cannot divide the time
45:19 indefinitely so uh in this lecture I
45:23 would like to tell you about the physic
45:31 will tell you about uh an application of
45:35 uh those at P traits and uh especially
45:42 uh uh time application on to
45:52 ization okay uh it's
45:56 quite obvious that if you
46:00 need uh to make an Ito second then you
46:04 need two things first of all you need a
46:08 short uh period for the light and uh uh
46:14 this means high frequency and this means
46:18 uh that you have to go into a domain
46:23 which is soft X-ray and
46:29 xrays uh then what you need is a cerent
46:34 bandwidth which is large enough to
46:36 support the otherc PES and uh uh this is
46:44 a condition that must be
46:50 fulfilled so uh the armonics that and
46:57 ler talked about before is or seems to
47:03 be a perfect candidate to produce uh
47:10 PES first of all uh the frequency is
47:14 high and it can be up to 100 times the a
47:20 frequency of the lasers and then the
47:23 bandwidth is quickly very wide and so
47:28 all uh the qualities are supposed to be
47:34 here so uh indeed back in
47:39 1992 those two guys uh my old friend
47:43 farash Kyo farash and uh his
47:48 co-workers uh thought chabat thought uh
47:57 those harmonics are in Phase if they are
48:01 phase locked it's say and uh uh then in
48:06 the time domain that would correspond to
48:09 a sequence of periodic PES of very short
48:20 unfortunately at a time this calculation
48:24 by Andre and and uh
48:28 coworker uh seems to show that the phase
48:35 were not at all as hoped but there was
48:42 random uh absolutely random and uh so
48:47 except perhaps it in
48:51 the the cut off region where there are
48:54 no photons at all so yeah uh I come back
49:01 to this question a bit
49:05 later okay then I have to introduce you
49:09 to the above threshold
49:11 ionization uh process and for that I
49:15 will start with yeah Einstein photo
49:19 effect uh that was mentioned already so
49:23 Einstein has the idea that light is made
49:28 of photons uh and not of a field but of
49:34 photons and uh the photons have a
49:38 specific and definite energy of H new
49:43 the product of uh the plank constant by
49:49 frequency uh so an electron can absorb
49:54 or emit uh photons okay integer energy
49:59 of photons and now if the photon energy
50:04 is large enough then you can liberate
50:09 you can free one electron from the uh
50:13 the potential well in in rich
50:17 is okay so uh this is well known from
50:23 all the students and and the high school
50:27 students I guess uh the uh uh the
50:32 kinetic energy of the electron which is
50:34 freed is the difference between the
50:37 photon energy H new and the the uh
50:43 potential energy the electron is kept by
50:48 uh in the atom or in the
50:56 then uh that was the time of Einstein
51:01 1905 but uh in the 60s uh in 61 uh the
51:07 laser was invented by mayman and uh uh
51:13 actually it was possible to ionize an
51:16 atom with photons which were smaller
51:19 than IP and then you just had to pile up
51:24 a number number of photons for instance
51:28 here uh the the kinetic energy is equals
51:34 to 3 H new minus IP uh on on this uh
51:40 graphic uh so the the the study of this
51:45 MPI so-called MPI moton
51:49 ionization uh started in Russia at The
51:53 liida Institute in the
51:56 and there are a number of papers from
52:01 that okay and then I come to uh uh to
52:07 the the above threshold ionization or
52:14 know by measuring the kinetic energy of
52:17 the photo electrons it was immediately
52:21 seen that electrons are more energy than
52:26 than predicted by uh the Einstein photo
52:31 and by uh the the uh energy of the
52:36 electrons could be uh that energy
52:39 minimum three H2 minus IP for instance
52:44 in this case plus another Photon or two
52:48 other photons so uh you could see that
52:53 as as Peaks in uh the photo electron
53:04 uh how to measure the phase uh the phase
53:08 of the harmonics is the
53:11 the uh the thing that is the key to at
53:18 pulses and so how to measure the those
53:23 phas first of all you need a nonlinear
53:26 Optics process uh I'm not showing
53:29 proving that here but I ask you to take
53:36 so the problem was that harmonics were
53:41 not strong enough to uh uh to do those
53:47 uh multiphoton nonin Optics processes so
53:52 the solution was to make to mix the
53:56 armonics with a strong laser and uh this
54:01 would could result easily in in two
54:03 Photon ATI or two Photon
54:09 ionization so uh we have now this case
54:14 of two color two Photon
54:18 transition uh one is uh with a harmonic
54:23 or with a the photon which is large
54:26 enough and then we have ATI that is the
54:31 the atom absorbs one Photon more but one
54:34 Photon from the strong
54:38 so uh we could have also more
54:41 complicated things like that uh where we
54:46 have three colors to start from the two
54:50 two consecutive order harmonics and one
54:54 photo being absorbed and one Photon
55:00 emitted all right that's the key of the
55:03 measurements we have done and
55:11 1996 uh those three theorists from
55:19 M uh calculated that uh in if you have
55:27 ionized by uh two colors to start from
55:32 right two consecutive order
55:36 harmonics then you should have two peaks
55:41 uh one for each of these
55:44 colors and if you mix those two colors
55:51 then the atom can absorb two
56:00 Photon from harmonics and one Harmony
56:03 one laser Photon or absorb one bigger
56:07 Photon from the harmonics and emits one
56:11 Photon and since we know that those
56:18 uh all other harmonics they are
56:22 separated by twice the
56:25 uh laser frequencies twice the frequency
56:33 if uh one absorbs one Photon Las from
56:36 the laser and the other emits one Photon
56:39 from the laser you add it up to the same
56:51 this gives rise of course to an inter
56:59 uh okay uh I'm sorry for the equation
57:03 but uh uh the the result of this
57:07 interference is that the amplitude of
57:11 the middle Peak which is called the
57:14 sideband is uh given by uh uh this
57:22 uh mathematical formula
57:25 and in this formula uh the frequency is
57:31 uh the frequency at which uh this side
57:39 uh the the the phase difference which is
57:43 the thing that we are looking at uh
57:46 looking for is is this Factor here Delta
57:52 Q uh and so it's enough to change the
57:57 delay and measure uh the amplitude of
58:05 determine what the Delta fq is and
58:12 uh to determine the phase of the
58:15 harmonics or the phase difference of the
58:18 harmonics and uh to check if we whether
58:23 or not uh we have at the second
58:27 pulses uh on on top of this Delta fq uh
58:33 we there is a small
58:35 correction uh that had to be calculated
58:42 um I'll come back to that in in a
58:48 second okay uh how do we implement the
58:52 theory uh in an experiment
58:55 okay this is uh uh I'm not going to into
58:59 all the details here but the important
59:02 thing was a mask which was uh uh
59:07 dividing the beam the initial beam into
59:12 parts uh then we had a couple of glass
59:17 windows uh which could be oriented and
59:22 which introduced between two beams uh an
59:33 Precision uh then there is of course uh
59:36 the jet where the harmonics are created
59:41 is something which I called here a pin
59:45 hole which is just a hole in a piece of
59:49 uh of metal and uh this has a very
59:54 important important role as we will see
59:59 immediately okay uh this is
01:00:07 measurement of uh the armonic phases in
01:00:12 in our experiment 20 years ago and uh so
01:00:16 what you see here is the
01:00:19 Spectrum uh on the on the top box uh
01:00:24 Spectrum with no infrared without this
01:00:29 laser photons and so what you see are
01:00:33 the Peaks corresponding to the
01:00:36 harmonics okay then we introduce the
01:00:40 laser we superpose the laser to this
01:00:43 harmonic beam and we have more peaks in
01:00:47 in the uh um in the
01:00:52 Spectrum and those are the side bands in
01:00:55 between each of the initial initial paks
01:01:00 and the amplitude of the side bands
01:01:04 changes with uh uh with the delay all
01:01:08 right so uh once we have that we have we
01:01:13 can plot uh the different side bands
01:01:18 that we see on the Spectrum as a
01:01:21 function of the delay and uh uh we see
01:01:25 oscillations as predicted by the uh the
01:01:31 mathematical formula of
01:01:34 venar M and from this
01:01:39 oscillations one can derive the phase of
01:01:42 the harmonics the phase that was that
01:01:47 would decide whether or not we have uh a
01:01:53 to so it turns out that uh from this uh
01:02:01 from this phases the phes are very well
01:02:05 behaved uh not at all the
01:02:09 random things that was predicted by
01:02:13 antoan and uh and and
01:02:24 uh amplitude measurements and from the
01:02:27 phases measurement then one can
01:02:31 reconstruct the time domain of the of
01:02:35 the PES of the light and uh we had this
01:02:41 uh this uh train I mean train meaning
01:02:45 here a sequence of periodic PES and uh
01:02:53 the time the the the the per duration
01:02:55 was at that time something like 200 at
01:03:02 second that's much longer than okay that
01:03:05 was 20 years ago right
01:03:08 now uh probably fence will talk about
01:03:12 that but uh uh the PES have shrinked to
01:03:18 43 out of second right I think that's
01:03:22 the last number I I
01:03:27 thought okay uh yeah the question is
01:03:32 does this that's the calculation of I
01:03:36 that we saw a moment ago uh cont
01:03:39 contradict that uh I mean this uh this
01:03:44 Behavior which look completely random
01:03:47 and this one looks uh pretty nice
01:03:52 so is there a contradiction between the
01:03:58 uh okay I'm not uh going to talk about
01:04:02 the details which have been already
01:04:05 described by an but the question is this
01:04:10 angular distribution of the two uh
01:04:13 amplitude that interfere and that make
01:04:21 uh the phes look absolutely
01:04:27 uh that can be really solved with
01:04:34 uh very small and Sh things which is uh
01:04:40 probably uh the cheapest thing in our
01:04:44 experimental setup and so this is a
01:04:47 pinhole that isolates
01:04:51 one of the two amplitudes that creates
01:04:56 the the problem uh with the with the the
01:05:00 randomness of the faces so uh this is
01:05:05 done by just because of the angular
01:05:08 distribution is different and if uh we
01:05:12 put somewhere in the beam uh uh this
01:05:18 simple Gadget of uh uh a pinhole then
01:05:24 this suppresses completely one of the
01:05:29 interference uh amplitude and uh from
01:05:37 the if the interference is suppressed
01:05:40 then the behavior of the phase is
01:05:48 fine uh one word about the the small
01:05:52 correction you remember perhaps there
01:05:55 are two terms the the harmonic phase
01:05:58 difference and there was this small
01:06:01 correction uh the small correction has
01:06:04 made a terrific career in the past 10
01:06:08 years or so uh under the name of photo
01:06:12 ionization delay that's the technique
01:06:15 that was used uh to measure the time
01:06:19 delay between uh uh I mean the time
01:06:23 delay they taken
01:06:25 for uh the electrons to be removed in a
01:06:32 process uh well I put
01:06:37 some uh titles there but you can see in
01:06:44 that okay uh in one title there is
01:06:48 already zepto second coming so the
01:06:52 future is coming here
01:06:56 okay uh now I guess I have a few
01:07:01 pictures that have been provided by
01:07:04 Philip Balu of the laser we use at that
01:07:07 time uh that's not much of a picture but
01:07:12 uh at least I've been guaranteed that is
01:07:19 uh okay uh those are the two windows
01:07:24 that were uh used in the experiment and
01:07:27 in the setup that we used to
01:07:31 uh uh to control the the the delay
01:07:36 between uh the two beams uh and uh uh so
01:07:41 it's yeah uh the two windows this is a
01:07:46 window clearly uh on the left on the
01:07:49 right there is a small part of wind the
01:07:52 small central part is the window which
01:07:55 has exactly the same thickness as the
01:07:59 other one because uh it has been taken
01:08:02 ex from the other one and uh uh so yeah
01:08:12 again courtesy of Philip Balu uh d z and
01:08:20 syia um so this is not really
01:08:24 the usual the the uh the authentic one
01:08:28 the the old one which have disappeared
01:08:33 uh uh it it is a a replica which is
01:08:39 exactly the same and which has been
01:08:42 actually used in in an
01:08:46 experiment um so uh I like to show some
01:08:54 the our students at the time I mean
01:08:59 P which were I think in the audience
01:09:05 somewhere uh Philip Balu uh is here this
01:09:11 has uh provided a number of things and
01:09:17 uh one special mention is about arm hit
01:09:21 Miller Professor Miller
01:09:24 who not only invented this setup that we
01:09:28 have used in the experiment but also
01:09:31 invented this wonderful uh acronym of
01:09:36 rabbit uh whose explanation is is uh in
01:09:41 the title of this paper which came out
01:09:44 one year after the first one and is uh
01:09:48 uh reconstruction of Aon harmonic beat
01:09:52 by interference of two Photon transition
01:09:56 okay then you know
01:10:02 everything okay uh then I would like to
01:10:05 talk a little bit about an application
01:10:10 uh the the the subject of this second
01:10:13 part is the strong field double
01:10:20 ionization okay first I could show you
01:10:24 okay that's sure and
01:10:25 tell uh modern aob beam line in at at
01:10:33 so you see tube tubing and uh well the
01:10:41 um uh the the electron spectrometer is
01:10:44 down there uh the laser is somewhere in
01:10:47 another room and so laser beam is coming
01:10:51 through those tubes uh the the it's
01:10:54 under vacuum everything is under vacuum
01:10:57 because all those harmonics are XUV
01:11:06 um XUV or yeah soft xrays so uh
01:11:13 naturally now everything is automat
01:11:16 automatic in the first experiment we
01:11:18 were I mean we're turning the glasses by
01:11:22 head to start from so yeah uh all the
01:11:27 time um now it's completely automatic
01:11:31 and and uh what you see here is
01:11:34 a sequence of measurements and first of
01:11:38 all the laser are Kilz repetition rate
01:11:41 so it's much more uh accurate and and
01:11:51 uh double ionization I mean I mean once
01:11:54 you have extracted one electron for an
01:11:56 atom so you have an ion and if you try
01:12:00 to extract a second electron then the
01:12:05 the the work you have to apply to the
01:12:08 atom is about twice uh the the first one
01:12:15 uh it predicted from that that would be
01:12:20 much more difficult to extract the
01:12:23 second electron then to extract the
01:12:25 first one but okay an experiment or
01:12:30 several experiments in the
01:12:35 1924 uh showed that this was not at all
01:12:39 uh the case and uh uh that uh ionization
01:12:45 of double ionization
01:12:51 difficult so uh one of the explanation
01:12:55 was provided by uh those guys I mean
01:13:00 Paul kander and kfer kfer is here
01:13:05 somewhere uh and uh the idea is that uh
01:13:11 if you if you extract one electron in
01:13:14 the presence of a strong field this
01:13:17 electron can uh be accelerated by the
01:13:21 field and then uh right St back to the
01:13:25 nucleus where it started from and
01:13:28 extract another electron by a yeah e2e
01:13:37 uh sort of bilard balls right
01:13:43 uh so the probability of this sment is
01:13:47 is much larger than uh what expected by
01:13:56 multiphoton processes perturbative
01:14:01 processes okay uh now the experiment
01:14:05 that will be has been done in in
01:14:09 Columbus at Ohio State by uh those
01:14:14 students and and under the direction of
01:14:19 diaro uh is is the following okay first
01:14:24 we have this Trin of aoson pulses that
01:14:28 we can you know absolutely precisely
01:14:32 delay with respect to the uh to the the
01:14:39 uh the the optical cycle of the of the
01:14:43 laser so we can decide exactly at what
01:14:47 what moment at what time within the AOC
01:14:54 duration uh the electron will be ejected
01:15:03 detect or observe uh the return time
01:15:08 that of this electrons the time that uh
01:15:12 uh separates the emission from uh his
01:15:17 return to the to the
01:15:20 nucleus uh by observing the charge ions
01:15:25 and uh from the knowledge of the de the
01:15:30 the departure type and the return timee
01:15:34 we can uh we can reconstruct the
01:15:39 electron motion exactly uh so that's one
01:15:44 example of how you can use those atos
01:15:50 conules to uh control and and observe
01:15:58 Motion in in a in a strong
01:16:04 field just a quick look towards the
01:16:12 far all uh atos pules
01:16:17 are uh created by laser visible or laser
01:16:24 and uh uh harmonics now
01:16:29 uh the problem with the harmonics is
01:16:32 that they are not very powerful I mean
01:16:34 they are sort of weak and to observe
01:16:37 nonlinear processes with them we have to
01:16:41 mix them with a strong laser now uh at
01:16:45 the L light light coant light source uh
01:16:51 x-ray free electron on lasers which is
01:16:56 uh this small setup of 1 kilomet long or
01:17:00 something uh I'm finished uh
01:17:05 um people have already found that
01:17:09 they're able to create AOC isolated AOC
01:17:13 pulses with gwatt Peak power so that's
01:17:18 at least a factor 10 above the current
01:17:21 harmonics uh at the moment so maybe the
01:17:26 future of the the at is not in the lab
01:17:32 and uh not with our laser and harmonics
01:17:36 but with this LCS uh xray free electron
01:18:09 so now we have heard about how to
01:18:13 measure the duration of these short
01:18:16 light pulses and also how to create the
01:18:21 trains and uh also about applications in
01:18:28 science now we come to the creation of
01:18:32 individual short
01:18:34 lollies and we are going to welcome uh
01:18:37 professor and director fence Krauss so
01:18:41 please join me in welcoming
01:19:10 see good morning ladies and
01:19:13 gentlemen it is a tremendous honor to be
01:19:16 here and uh I thank the Royal Swedish
01:19:21 Academy for bestowing it on me
01:19:24 it's still hard to
01:19:28 believe I would also like to thank
01:19:31 um all persons in my life who supported
01:19:34 me helped me learn grow and achieve my
01:19:39 family my teachers in
01:19:42 Hungary my co-workers in Austria and in
01:19:45 Germany and our collaborators from all
01:19:51 world um so some of them will show up on
01:19:54 my slides and I already now cordially
01:19:58 thank them as well as the many more who
01:20:01 are not going to show up for their
01:20:05 invaluable contributions without which I
01:20:08 would certainly not stand here
01:20:17 gentlemen uh played a very special
01:20:20 role I ow them very very special thanks
01:20:25 and gratitude Arnold Schmid's uh uh
01:20:30 guidance and Paul kum's deep insight
01:20:33 into electron phenomena have uh
01:20:38 decisively influenced my
01:20:44 path this lecture is going to be devoted
01:20:47 to how ATC physics opens the door to to
01:20:53 uh the world of uh subatomic
01:21:00 electrons which were inaccessible to
01:21:04 human observation until the turn of the
01:21:11 Millennium for decades after following
01:21:16 its Discovery this elementary particle
01:21:20 was thought when when Bound in atom to
01:21:23 be revolving around the
01:21:29 eventually quantum mechanics uh revealed
01:21:33 that subatomic motion can only emerge by
01:21:39 exciting an electron from its ground
01:21:45 state to a superposition of stationary
01:21:49 States and the result
01:21:53 uh temporal variation of the electron
01:21:58 probability density constitutes the
01:22:02 closest analogy to classical motion
01:22:04 exemplified here by the dipole
01:22:09 oscillations uh in the 1
01:22:12 s2p superposition state in
01:22:17 hydrogen one of uh the messages that I
01:22:21 would like you to take home from my
01:22:23 lecture is that control is absolutely
01:22:28 Central to time resolved observation and
01:22:34 example the control of electrons current
01:22:40 in macroscopic uh nanoscale but yet
01:22:45 macroscopic circuits with microwave
01:22:53 the capturing of fast varing electronic
01:22:56 signals in microscopic circuits
01:22:59 analogously the control of electron
01:23:03 current by the electric field of
01:23:06 light opens the door to
01:23:11 observing and eventually even
01:23:14 controlling um electron phenomena in
01:23:18 atomic and even subatomic dimensions
01:23:24 but how actually to control the electric
01:23:27 field of light in order to be able to
01:23:30 control with this controlled force that
01:23:33 it exerts on these electrically chared
01:23:36 particles to control the atomic case
01:23:39 atomic scale electron current four Nobel
01:23:42 prize winning Concepts paved away uh
01:23:47 lasers uh utilizing nonlinear Optics and
01:23:51 CH PSE amplification
01:23:55 yield Ultra short very powerful Ultra
01:24:00 pulses whereas uh the control of the
01:24:03 laser frequency comp can lead to pulses
01:24:08 with um a controlled
01:24:11 waveform controlling the waveform of
01:24:14 light actually means that we have to
01:24:18 shape we we we shape the electric field
01:24:21 within its OS ation
01:24:23 period what does this mean well what it
01:24:26 technically requires is an octave
01:24:29 spanning bandwidth lacking lasers with
01:24:32 such a gain bandwidth we have no other
01:24:35 choice but try to broaden the
01:24:38 spectrum of um uh the
01:24:42 pulses uh outside the laser and that's
01:24:46 exactly what uh we can do in a wonderful
01:24:53 invented in Milano by orio
01:24:56 swelto Santo de Sylvester
01:25:00 maroli um a we can send a short laser
01:25:05 PSE through a gas field Hol fiber Where
01:25:09 It suffers it is subjected to cell phase
01:25:12 modulation and this nonlinear process
01:25:15 broadens is its frequency spectrum the
01:25:20 result is a um pulse that carries a
01:25:24 frequency sweep and with a strongly
01:25:26 broaden spectrum and these pulses can
01:25:30 subsequently be compressed by another
01:25:33 wonderful device chirped multi-layer
01:25:36 mirrors invented in Budapest by Robert C
01:25:42 F and uh these two uh devices together
01:25:47 are able to actually advance fcond
01:25:53 technology to its limits to the Limit
01:25:56 that is imposed by nature to the limit
01:25:59 of a single wave cycle so thanks to
01:26:02 these two technical
01:26:12 powerful pulses consisting of a single
01:26:15 intense oscillation cycle became
01:26:20 available with controlled carrier
01:26:24 envelope phase since 2003 and with this
01:26:27 leather development they actually opened
01:26:30 the door to Precision at a second
01:26:32 Metrology but before I come to that I
01:26:35 just would step back couple of years to
01:26:40 briefly review the first ATC generation
01:26:43 and measurement experiment um in Vienna
01:26:48 multicycle driving laser pulses used in
01:26:51 the experiment of N and Pier were
01:26:54 replaced by pulses comprising a
01:26:58 single wave cycle single very intense
01:27:02 cycle when when focused on atoms the
01:27:07 extremely rapid turn on uh in these
01:27:11 pulses um implies unprecedented and
01:27:16 unprecedented rate and temporal
01:27:19 confinement of ionization and a direct
01:27:25 very um short very brief
01:27:29 um emission of XUV light from the high
01:27:33 or the harmonic generation process
01:27:36 particularly if we um filter the highest
01:27:42 order harmonics uh in our case with a um
01:27:47 bent pass multi-layer which also focuses
01:27:50 the beam to a second G jet of Neon gas
01:27:55 where the XUV pass KN electrons free uh
01:28:00 in the presence of the Fus cycle laser
01:28:02 field and actually provided the first uh
01:28:06 um well first very strong experimental
01:28:11 indication uh of the existence uh of uh
01:28:16 an isolated subf to Second pulse in a
01:28:20 series of experiments performed by by
01:28:22 Mel henchel and rhand kimberger in our
01:28:26 Laboratory um at that time at the
01:28:28 Technical University of Vienna back in
01:28:32 2001 couple of years later laser PES
01:28:36 with controlled W form enabled Precision
01:28:43 metodology by implementing an ingenious
01:28:48 concept of Paul Corum the concept of a
01:28:51 life field driven streight camera the
01:28:54 XUV PSE again hits neon atoms again in
01:28:58 the presence of the laser field but this
01:29:02 we measure the time of flight of those
01:29:08 are catapulted from the
01:29:11 atoms parallel to the direction of the
01:29:19 field depending on the moment of release
01:29:23 the laser field accelerates or
01:29:26 decelerates them and you see here from
01:29:30 this equation that now physics further
01:29:33 simplified after the electron is
01:29:35 liberated the laser field is so strong
01:29:37 that actually we can describe the motion
01:29:40 in a very good approximation classically
01:29:42 just uh uh Newton's equation is being
01:29:45 solved here to uh to uh calculate this
01:29:49 Delta P which is the kick uh
01:29:52 in the back of the electron to move it
01:29:55 faster or slower and this very kick uh
01:30:00 is depending on the moment of release
01:30:02 and this actually Maps the temporal
01:30:05 profile of the XUV PSE to a final
01:30:10 momentum distribution of photo
01:30:13 electrons recording these XUV induced
01:30:18 laser field streaked photo elect on
01:30:22 Spectra as a function of delay results
01:30:26 spectrogram which allows an ambiguous
01:30:33 retrieval of both the laser vave form as
01:30:37 well as the complex amplitude of the
01:30:41 atcond XUV P so the this this experiment
01:30:45 actually demonstrates uh how control
01:30:50 enables observ ation this time on an ATC
01:30:54 time scale and actually renders the
01:30:57 basic tools the ATC varying force that
01:31:01 this light electric field exerts on
01:31:04 electrons and the at a second duration
01:31:09 emission available for realtime
01:31:12 observation and control of electron
01:31:14 light phenomena with these tools in
01:31:16 place we can set out
01:31:18 to perform at a second uh time resolve
01:31:22 spectroscopy you have um uh learned from
01:31:26 the wonderful talk of an how actually
01:31:29 such spectroscopy can be done by using
01:31:32 XUV pses to kind of trigger the motion
01:31:36 like ionization and use the the uh
01:31:40 basically laser field to capture the
01:31:43 motion right here I turn the game around
01:31:47 and I will show you an example where we
01:31:50 use actually the the at a second varying
01:31:53 and at a second controlled force that
01:31:56 our single cycle is a pulse exerts an
01:31:59 electrons to trigger the motion and use
01:32:03 the atcond XUV PSE to actually capture
01:32:06 it to take the uh snapshots with a delay
01:32:11 and try to reconstruct the motion from
01:32:14 the series of snapshots so basically we
01:32:17 just use this single cycle laser field
01:32:22 ioniz an atom actually in the same Focus
01:32:25 which we used before to to to
01:32:28 characterize the tools uh by at a second
01:32:32 streaking and this time we we uh put
01:32:36 some other guas there in Krypton gas and
01:32:41 the single cycle laser field actually
01:32:43 ionizes this gas and we uh send the XUV
01:32:48 pa uh with some delay through the
01:32:52 ionizing medium and analyze its uh
01:32:55 Spectrum it's the the the energy
01:32:57 distribution of the photons contain this
01:33:00 in this ATC XUV probe and uh when when
01:33:04 the system starts
01:33:07 ionizing then we see some changes in the
01:33:10 Spectrum and that's what with the help
01:33:12 of some Theory as we will see in a
01:33:14 moment uh gives us information about how
01:33:18 the electron is actually liberated and
01:33:20 is coming out uh is is catapulted out of
01:33:23 the atom so obviously this kind of
01:33:26 measurement is able to provide Direct
01:33:28 Time domain inside into what I think can
01:33:34 arguably the most fundamental strong
01:33:37 field phenomenon Optical field induced
01:33:40 tunneling here uh we can observe how
01:33:43 this process in this case Crypton in
01:33:46 Crypton atoms is substantially confined
01:33:49 to the central wave cycle of a cosine
01:33:51 shaped near infid waveform we which we
01:33:54 have measured simultaneously by ATC
01:33:57 streaking so so uh uh remember two at a
01:34:01 second techniques are being employed in
01:34:03 this very experiment at a second
01:34:05 transient absorption spectroscopy which
01:34:08 leads to the transient absorption
01:34:10 Spectre I'm going to show you in a
01:34:11 moment and simultaneously at a second
01:34:13 streaking to learn precisely at which
01:34:17 moment actually um or what is the what
01:34:20 is reference uh in the time on the time
01:34:22 scale where where is the time zero with
01:34:25 respect to which we we delay our at a
01:34:30 PSE um um one of the exciting um
01:34:34 discoveries that we that we learned from
01:34:36 this experiment was that that the about
01:34:39 700 atcond rise time of the ion
01:34:42 population turned out to be
01:34:45 significantly slower uh than predicted
01:34:48 by the quasistatic adk theory so this
01:34:51 this this kind of non-diabetic tunneling
01:34:56 um that could not have been discovered
01:35:03 spectroscopy when subjecting these
01:35:05 Krypton atoms to this strong field
01:35:07 actually actually the electrons can be
01:35:10 liberated from two different uh um uh
01:35:14 so-called spin orbit Quantum states of
01:35:17 the 4p subshell of
01:35:20 Krypton uh with comparable
01:35:23 probability this means that the hole in
01:35:26 the electron cloud of this Krypton atom
01:35:30 is created in a superposition State
01:35:33 because the whole can be either in one
01:35:36 or in the other uh spin orbit State
01:35:41 remember we uh learned at the beginning
01:35:43 of this uh lecture that putting the
01:35:47 electron or in this case the hole same
01:35:50 thing in a superposition State means
01:35:54 motion subatomic
01:35:58 indeed the the sequence of transient
01:36:02 absorption spectra that that is shown
01:36:05 here in a force color representation
01:36:09 does exhibit uh pronounced temporal
01:36:13 variation periodic temporal variation
01:36:15 for increasing delay of the uh XUV probe
01:36:21 the 6 fcond delay period actually
01:36:24 precisely corresponds to the 0.7
01:36:28 electron volt energy separation between
01:36:30 the two uh spin orbit levels to develop
01:36:36 film from these uh these transient
01:36:43 spectra um captured with 150 atcond
01:36:53 the photographer's job here is taken
01:36:56 over by theorists and I
01:36:59 would very much like to to
01:37:02 join uh previous speakers and and Pierre
01:37:05 to emphasize how incredibly important
01:37:08 the role of of theorists was in the
01:37:11 emergence of Ed second science so here
01:37:13 you see the result of that modeling and
01:37:15 the excellent agreement between Theory
01:37:18 and experiment allow us actually to to
01:37:21 reconstruct the atcond snapshots of the
01:37:25 whole density uh
01:37:28 distribution versus time delay and even
01:37:32 the initial Quantum phase between the
01:37:35 two components of the of the um wave
01:37:40 bucket of this hole that we that we
01:37:42 create so from the all this information
01:37:44 we can we can completely
01:37:48 reconstruct the uh subatomic motion
01:37:52 following tunneling ionization here in a
01:37:55 slow motion replay with a temporal
01:37:58 magnification of uh um 10 to the
01:38:03 15 um when rendering these motions
01:38:06 accessible to human observation at a
01:38:08 second spectroscopy furnishes us with a
01:38:11 temporal magnifying power that is
01:38:14 equivalent to the combined magnifying
01:38:17 power of a space telescope and an El
01:38:23 microscope in the words of Eva Olson we
01:38:27 can now open the door to the world of
01:38:29 electrons at a second physics gives us
01:38:32 the opportunity to understand mechanisms
01:38:34 that are governed by electrons The Next
01:38:36 Step will be utilizing them but which
01:38:40 applications are likely to yield in the
01:38:43 world of Max Blan the richest and most
01:38:48 lasting gains that we can possibly draw
01:38:52 perception if you accept that this may
01:38:56 be a right question we have already
01:38:58 Master what an rubic considers to be the
01:39:02 most important and difficult
01:39:04 task um namely finding the right
01:39:07 question my tentative answers appear to
01:39:11 dives into the delicate details of light
01:39:15 electron energy exchange at the nanoc
01:39:17 scale and into the molecular composition
01:39:19 of functional con
01:39:21 ents uh bof fluids blood body fluids and
01:39:25 tissues of living
01:39:28 organisms for tackling um contemporary
01:39:32 challenges uh ever since the beginning
01:39:35 of uh the New Millennium advancement of
01:39:38 Professor processor performance was
01:39:43 miniaturization wi the clock rate
01:39:46 actually determining the speed of
01:39:49 processing was stagnating at about 10 uh
01:39:53 gahz uh can ATC physics possibly
01:39:58 contribute to exploiting the fourth
01:40:01 dimension for further advancing
01:40:04 electron-based signal processing and
01:40:06 other contemporary Grant question
01:40:09 relates to the million of premature
01:40:12 deaths on this planet year by year
01:40:15 mostly in low and middle- income
01:40:17 countries uh most of these deaths could
01:40:21 be prevented by early intervention
01:40:23 following of course early detection of
01:40:26 the condition urging the Quest
01:40:31 for affordable health monitoring can the
01:40:35 molecular composition of human blood
01:40:38 provides sufficiently Co comprehensive
01:40:41 information to serve as a basis for
01:40:45 populational health scening and can ATC
01:40:47 physics possibly contribute to
01:40:49 that in order to be able to tackle uh
01:40:53 such questions uh at a second Technology
01:40:57 based on complex vacuum systems has to
01:41:00 become simpler and more powerful
01:41:04 and uh fuse cycle or actually single
01:41:07 cycle light recently enabled this owing
01:41:10 to its ability to realize the same
01:41:13 process that we've just studing in atoms
01:41:16 actually in in wide Gap solid namely
01:41:19 Optical Fielding used electron
01:41:21 tunneling but why is this extreme
01:41:23 temporal confinement so essential here
01:41:25 because um no solid matter could survive
01:41:31 could otherwise survive the required
01:41:34 critical field strength of about two w
01:41:36 per angster only by confining this
01:41:39 extreme field strength to a single
01:41:41 oscillation cycle can um irreversible
01:41:46 avoided tunneling then occurs within a
01:41:49 fraction of the the central field cycle
01:41:52 in a cosine shaped waveform this means
01:41:54 actually again less than 1 FC for
01:41:57 visible or infrared light subf Toc car
01:42:00 injection replaces subf Toc XUV light
01:42:04 and thereby obviates the need for vacuum
01:42:07 systems for a class of applications
01:42:10 extraordinarily important for advancing
01:42:15 namely uh the atcond control and probing
01:42:19 of veillance and conduction invent
01:42:21 carrier Dynamics in a primary step subf
01:42:24 to Second carrier
01:42:26 injection is uh used for optical field
01:42:29 sampling uh by implementing it in a
01:42:34 volume um where the test field uh can
01:42:38 separate the injected electrons and
01:42:40 holes towards two electrodes and and uh
01:42:44 Drive actually a current in an external
01:42:47 circuit connecting these two electrodes
01:42:49 and here you see this current
01:42:51 uh is a function of delay with respect
01:42:53 to the red infrared test field uh which
01:42:56 is obviously measured with with a good
01:42:58 uh Fidelity as confirmed by at a second
01:43:03 streaking now this ability to precisely
01:43:06 measure the oscillating field of light
01:43:09 um offers a new probe for ATC phenomena
01:43:12 in the form of the electric field of
01:43:14 light all the way from the infrared
01:43:17 meanwhile to the
01:43:19 ultraviolet it can actually
01:43:22 probe the arguably most fundamental
01:43:26 consequence of any light matter
01:43:28 interaction the displacement of
01:43:34 charge density briefly
01:43:39 polarization it is embedded it is
01:43:43 inscribed in the electric field of the
01:43:46 transmitted wave referencing this
01:43:48 transmitted field to the input field
01:43:50 actually allows us to uh unambiguously
01:43:54 retrieve at least for a thin medium the
01:43:58 polarization uh together with its
01:44:00 driving field it actually uh directly
01:44:03 yields by means of this simply formula
01:44:06 the a rate of energy exchange between
01:44:09 the field and the electronic system if
01:44:12 you now integrate this rate from a
01:44:14 certain time before the electric field
01:44:17 is coming in uh to to a certain time
01:44:20 point then we get basically the
01:44:22 transferred energy and that's what I'm
01:44:25 showing you here for an insulator and
01:44:28 semiconductor subjected to strong
01:44:31 Fields um uh for the highest field field
01:44:36 strength uh the energy transfer appears
01:44:39 to be completely irreversible uh so
01:44:42 basically the transferred energy just
01:44:46 stays there after the laser p is
01:44:48 over but for for for reduced field
01:44:52 strength what we see is that actually
01:44:53 the field can completely reverse this
01:44:56 energy transfer this is the yellow curve
01:44:59 at least for the six Photon band capap
01:45:03 and this is a very important regime
01:45:05 because because such a reversible
01:45:07 process is really ideal for uh for
01:45:10 dissipation Free Ultra fast signal
01:45:12 processing this resume is completely
01:45:13 missing in the two Photon uh bandap
01:45:16 medium where reactive and dissipative
01:45:19 nonlinearity always appear in
01:45:23 combination these studies actually
01:45:25 showcase how uh real time exess to the
01:45:28 light electron energy transfer explores
01:45:31 Optimum conditions for Ultra fast opto
01:45:34 electronic signal manipulation we have
01:45:36 now seen how light field sampling and
01:45:40 the oscillating light as a probe may
01:45:44 help Advance Electronics in the
01:45:47 remaining yes few minutes um I would
01:45:50 like to address how the same technical
01:45:52 capability provides
01:45:54 exess to minuscule changes in the
01:45:58 molecular composition of human blood
01:46:01 plasma and which is a sensitive
01:46:04 indicator of Health disease transitions
01:46:07 to sense these transitions we
01:46:10 propose instead of searching for
01:46:12 individual biomarkers actually accessing
01:46:15 the global molecular
01:46:17 landscape Via Field resolved spectroscop
01:46:20 to this end we expose human blood human
01:46:24 blood plasma I should say to single s to
01:46:27 a single cycle infrared laser pulse
01:46:30 which coherently excites molecular
01:46:34 vibrations within its spectral B the
01:46:36 vibrating molecules in turn radiate
01:46:39 coherent infrared waves in the wake of
01:46:42 the excitation the resultant signal
01:46:44 which you see here is
01:46:47 characteristic of the molecular
01:46:49 composition of of the sample we capture
01:46:53 this electric field molecular
01:46:54 fingerprint with highly sensitive ATC
01:46:57 Metrology this fingerprint signal is
01:47:00 expected to change whenever emerging
01:47:03 abnormalities change the samples
01:47:07 molecular composition which we recently
01:47:10 verified for several chronic conditions
01:47:13 such as cancer cardiovascular and
01:47:15 metabolic disorders as a prominent
01:47:18 example we compare 470 samples of lung
01:47:22 cancer patients with the same number of
01:47:25 sample of of samples of reference
01:47:27 individuals free from cancer briefly
01:47:32 controls with the two cohorts being
01:47:35 carefully matched regarding um the
01:47:37 distribution of the subjects age and
01:47:40 other parameters these are the electric
01:47:43 field molecular Fingerprints of all
01:47:45 those samples clear
01:47:48 differences come to light between the
01:47:51 two cohorts some thousand Fant seconds
01:47:54 after the exitation peak where molecular
01:47:56 emission starts dominating over the
01:48:00 excitation we can now quantitatively
01:48:02 analyze these differences in terms of
01:48:07 gaps between the adjacent zero Crossings
01:48:10 of the oscillatory signal briefly half
01:48:13 cycle gaps here we show the mean and the
01:48:17 standard deviation of the half cycle Gap
01:48:21 what I would call spectroscopic markers
01:48:25 more than 350 of them this time
01:48:28 evaluated from the Fingerprints of stage
01:48:31 one to stage four lung
01:48:35 cancer from the Fingerprints of the
01:48:39 controls and most importantly the
01:48:43 differences between the two cohorts
01:48:46 these cancer induced signal uh cancer
01:48:49 induced changes in the half cycle gaps
01:48:51 range from tens of oscs to a couple of
01:48:54 fent seconds here we plotted uh these
01:48:58 lung cancer induced changes in half
01:49:01 cycle gaps for different changes in
01:49:04 comparison with the spread of controls
01:49:07 the efficiency with which a well-trained
01:49:09 algorithm is capable of distinguishing
01:49:14 controls uh critically depends on this
01:49:17 comparison the classification efficiency
01:49:19 can improved either by increasing the
01:49:22 the the disease in use signal or by
01:49:25 reducing the spread of
01:49:28 controls the cancer induced signal
01:49:31 increases for progressing stages and so
01:49:35 does the classification
01:49:38 efficiency the so-called area under the
01:49:41 curve these EU uh values are
01:49:45 promising uh for non metastasized lung
01:49:49 cancer how however they could be even
01:49:52 further improved by reducing the spread
01:49:55 of controls even at the current stage of
01:49:58 development of infrared fingerprinting
01:50:00 and that's exactly what our computer
01:50:03 modeling predicts for referencing each
01:50:07 individual cancer
01:50:08 fingerprint to a set of controls
01:50:11 collected from the same individual
01:50:13 before Contracting the disease the
01:50:15 spread of these controls is much reduced
01:50:20 much reduced thanks to a strongly
01:50:24 reduced within person variability of the
01:50:26 infrared fingerprints over time as
01:50:28 compared to the spread in in a healthy
01:50:31 control group we pursue proving this the
01:50:35 predicted performance um uh uh in a
01:50:39 longitudinal follow-up study in Hungary
01:50:41 the predicted above 90% detection
01:50:44 efficiencies constitute unprecedented
01:50:47 values for stage one to stage four lanen
01:50:51 so the price to be
01:50:52 paid for this early detection and
01:50:56 protection uh against being diagnosed
01:51:00 with the deadly stage four will be a
01:51:03 yearly blood test the study in Hungary
01:51:06 May reveal that uh infr
01:51:09 fingerprinting is able to uh
01:51:12 screen other severe chronic conditions
01:51:15 at an early stage and consequently it
01:51:18 affordable for if it will become
01:51:21 affordable for screening whole
01:51:24 populations May save millions of lives
01:51:29 year I take the Academy's decision as a
01:51:33 mandate for the pursuit of this very
01:51:36 goal with utmost
01:51:39 determination and as a mandate uh for
01:51:42 exploiting our increased visibility for
01:51:46 the benefit of the children in Ukraine
01:51:50 who are already dreaming uh of joining
01:51:54 vladislav from Lum number 10 in maranets
01:52:01 line just as all other children anywhere
01:52:05 else they deserve a chance to realize
01:52:09 dreams and we badly need all of them we
01:52:14 badly need all of them to carry on once
01:52:16 our own time comes to an end thank you
![Welp, Here's what the Fed *Just* Said [Fed FOMC Minutes]](/_next/image?url=https%3A%2F%2Fi.ytimg.com%2Fvi%2Fl8u23oq1E9E%2Fhqdefault.jpg&w=3840&q=75)
