 The thing is about time and time. It's a very special and unique to a great speaker, Ralph Kohnsberger, who will learn us about a bunch of options in quite different regimes, I guess, in the future. But I hope he will actually stimulate some new thoughts or, among us, that he should use the normal, physical or optical potions. By looking into what is really possible with advanced life sources and material science today, we are going to make a very, let's say, precise history of experiments. So I will make a very long introduction to you, Ralph Kohnsberger's PhD degree in 1994. I have come from Hanbrook University, and same year as me, so it's been a good year. And then we went on to Kohnsberger, to the advanced social science department at the International Laboratory in the States, nowhere. Kohnsberger University spent a few years there, went to a big university in Munich, and then came back again and spent quite some years in 2003, being a senior scientist at the DC, the Dutch University of Kohnsberger, a number of the wise and personal, but since also two years ago, in 2020, Ralph has been appointed as a full professor at the University of Vienna, and also he's made sure to do just the same thing. So you look very much forward to hear about this one type of very interesting, or one type of very interesting thing. Thank you very much, Michael, for your question. And for the invitation to come here for the first time, I'd like to thank you all. I enjoyed the very much, and I think there are always two challenges that Kohnsberger meets for Kolopium in such a setting. First of all, the speaker might be from all the exposure and discussions too tired, at the end of the day, for our Kolopium. And it was already exciting, so I think I have enough adrenaline to do this presentation. And second, another challenge is to that he might think that by listening to all the colleagues here in the department, he could have changed and adapted the content of the presentation to the audience better. So this is, of course, not possible anymore, but I hope I can match this and address a lot of your audience here in the afternoon. So, yeah, let's get started. So this talk is about light. And as the title says, it speaks to a light, and we didn't have something like imaging in the title. So this is the broader sense of application of photonics, which is basically the applications and science of light for applications and applications of light that have fascinated mankind for centuries, resulting in numerous applications in daily life. So I've just collected a few sketches from the internet, and we are all aware of the photonics. This is basically almost everywhere. So we have laser processes, like the welding, the filtering, the scanning, and so on. We have a lot of things for data and transmission. We have all kinds of imaging, and spectroscopy, the protons. We have harvesting of solar energy, solar panels, EVB and blu-ray data storage, and relighting, and so on, and so on, counting communication. So it's just natural to explore photonics concepts, basically all the entire electronic spectrum, which includes also fixed rates. So once I've looked back, actually the evolution of present-day photonics technologies was not always straight forward, but we counted the number of e-tools where a very prominent one was taken by a group of German fellows called the Syphotons of the Schildburg Art. So those of you with the German roots or contact with Germany might know that this might be considered one of the first things to continue with nuclear light. So the Syphotons, the tail, is saying that they filled the tower hall and dropped up the windows, and to mitigate this problem, they tried to collect light and boxes and move it into the tower hall. I mean, this was nowadays we know that this is not a concept to save money for public communities, of course. But anyway, I mean, this is the tail that reflects some kind of personal purpose to control light. You know, although this are more advanced versions available, and some examples about the sake of completeness, I have collected here, so we know that light can be actually put into boxes, into penities, for example, and into other burrows where actually we can achieve very high key factors. This is one of the many one of the 20 years ago publication. This is some fragments where I keep the other part of it. I'm trying to keep it to act very efficiently, with a part of the dot. And other type of resonators like this, with the gallery, one say, achieving higher quality factors where the light is propagating directly inside of this this here. And it's all invisible with a non-storage type of light. And this concept was called the study of light matter interaction, basically on the level of the single quarter of light and matter, single four dots. And this is eventually decided in the Felix Newell Prize 2012 of Russia and why that, and we see the concept of putting light into boxes was not some people actually work with it the other way. And the question is can this be achieved in the ecology as well? Of course we have Newell Prize also, but let's first try to put X-ray sets of boxes. And the answer to the question is yes we can we can confine X-rays as standing waves in cavity-like structures which are layered systems like sketched here where the particular properties, optical properties of matter for X-rays have to be considered. So there is actually which needs some explanation where you really have to be attentive now because that is a central concept here to know in terms of all the effects of perfection of matter for X-rays. So X-rays penetrate matter very easily, so the effects of perfection is close to one. It's not exactly one, it's one minus delta. And this delta is of 10 to the minus 5 to the 10 to the minus 6 it depends on the electricity, it depends on the wavelength. I don't give too much probability here. We can all be able to see the value that needs to the fact that any material is optically thinner than the vacuum from the perspective of X-rays. So the transition from vacuum into a material is the transition from an optically thin material. That's a little bit counterintuitive we are all used to the other way around, but that means that at this interface vacuum or air to matter we have total reflection under angles measured to the surface of only a few milli-radials. At very shallow angles we encounter total reflection of X-rays. And that is illustrated here so to give you a favor one degree on angular degrees 17.5 milli-radials. So one milli-radial is a quite small angle and that is measured to the surface. So yeah, the typical layer systems this is a I don't know if I talk about that but this is actually the basis for studying thin film system for X-rays. When there is an established technique in X-ray science to study the properties of thin films for X-rays there is nothing more than that but we are using this for building divisions. And what it is in this space here is a little bit different from what I've shown before it is a system consisting of two palladium layers which are sandwiching carbon layer which is strange. So you need of course to respond to the entire project. Yeah, so that means I have an SN coupling that is possible where you can actually here you have the depth on the view the measure of thickness of the layer. So we are talking about thicknesses of a few nanometer so we have zero as the surface 10, 20, 30 nanometer and we have actually higher penetration depth of the radiation coming here incident on the surface and penetrating the material, the thickness of this layer is smaller than the penetration depth so the radiation can travel cool this thin layer into the guiding layer here of that wave guide which is actually a planar wave guide so it's a cavity in that direction it's a cavity in this direction and the wave propagates in that direction so we have to optimize the that is a critical value of the thickness of that layer which means to be only a few nanometer so that the radiation can come out of this layer so it's sufficiently high in activity for the radiation that is inside due to the propagator and then the result of this propagation is the formation of the standing wave is the first order mode with an enormous enhancement of the normalized fluid intensity inside of the layer compared to the here it's a factor of 25 to reach a particular angle and the quality factor however compared to the futures and short cavities is rather low, we are in the range of say about 100 so it's a bad cavity in the quantum of the fluid energy but that isn't bad for what we want to do so it's a bad cavity but if we want to have high quality factors we can still shift this to the atom that we put into the cavity so we need long lift topic levels in the actual activity instead and that is actually shown here what possibilities do we have there are transitions in the electron of binding energies of the electron shells shown here electron shell nucleus so that's actually coming to the core of the problem here but focus my attention here on the nuclei of electric magnetic levels on the nuclei that actually also have better energies in the regime of arc x-rays so to put it in perspective we all know the electron binding energies of having the other shells in the electron of the regime the core electrons are found with the electron volt binding energies so of course obviously we have traditions which emit in the recombination emit which raise the arc x-ray regime the same is the case for nuclei which have low lying levels which are in this case in the field of electron volt range it's under low lying levels of the nuclei in body other levels the electromagnetic levels in the mega electron volt regime because there is a binding energy regime of the protons and neutrons in the nucleus so we are interested in those here so we are across the model here we have some traditions for example after photo absorption and this needs to come to second life type of the portholes here we have nuclear fluorescence and we have nanoseconds to really second life types of nuclear levels and so in the nuclear levels these levels are pretty long lived and why is that by the way the burst power isotopes these electromagnetic levels of the nuclei are belonging to the so called burst power isotopes because those small energies the emission and absorption of protons addressing these two level systems here are particularly occurring without recoil because the electrons are bound to the solid they are so strongly bound that the recoil energy is much smaller than the typical thermal energies so that the recoil that is imparted which is in the regime of two or three milli-electron volt is much smaller than these thermal energies so the recoil energy cannot be absorbed by the solid excited photon which is so much higher so that there is no chance for other chance than for the whole solid even the recoil partner for the photon that is emitted so that means it's basically if you don't know the recoil energy momentum squared by two times the mass of the emitting object the recoil energy is basically zero so that is the recoil is emission and absorption which is forming the ground for the burst power which is a little bit of a little advice already three years after the discovery of that thing because there was a number of applications a number of other burst power isotopes in this power we are listed a few and you see they cover the vision energy range we talk about six-electron volts up to almost 30-electron volts here in that regime here are the line widths actually the resonances are very sharp higher than 57 which is the one that is mostly used as a linear line width of 4% non-electron void only so it's a relative resolution in a relative bandwidth of three times 10 to the minus 13 that is an enormous expected resolution but there are other isotopes which super-seem this like zinc, spandium or thorium 229 which is has made it even in the daily press sometimes because this would actually be a sharp nuclear transition qualifying for a nuclear clock that would eventually monitor the time dependence of fundamental constants in nature that it's hypothesized the consequence of the expansion of the universe so these extremely sharp conditions could be used for extrematology and coming under science but here we are more down to earth so to say it is higher than 57 so the lifetime is very long if you can draw this here the time my age power was having 40 nanoseconds the lifetime is so long because compared to the nuclear dimensions the wave function of the photon the wave length of the photon is quite long so the overlap interval is small that's why there is a small probability for the photon being emitted from the atom from the nuclear that's why the lifetime is so long and it is an experimentally easily accessible for genes and that is what I want to do I have to set the ground for the poles of course to explain the working force here and that is the higher than 57 as a torque higher than 57 as a natural it's about 2.2% of all natural occurring iron it's higher than 57 as a torque and we typically buy it in which form to make the layers out of it and here are again the parameters it's a basically ideal level system here is actually shown the atomic scattering amplitudes as a function of energy so here would be what is shown here is the absorption edge the 7.1K the absorption edge of the K-shell electrons in the atom with their special dependence and compared to that we have here an enormous large scattering amplitude of the nuclear resonance however this is actually an almost textbook like the complex Oretzian contributions of the real and imaginary part of that resonance you see the dispersive part not the part here actually enter here so these quantities actually we have to put together to get the right index of perfection including if you want the part of the nuclear resonance here so that's all optics are visible and you can see a nuclear dispersion with an index of perfection concept that's taken into account with resonance B8 that's what I said already and yeah I don't have time to explain everything about reservoirs but possibly I just want to explain to you the modern version of this only 25 years old now reservoirs across the reciprocal radiation not only one that we call the energy spectrum with the Doppler drive and the radio and the source and measure the absorption profile and measure these sharp absorption lines actually but since lifetime is so long it can convert this method also in the time resolve version and this works with the signal with the pulse typical radiation shown in this animation here is a sample for having some iron 57 atoms that are illuminated with a broadband pulse here with a short pulse and the atoms are excited in the material and then they re-radiate their respective energies so in the magnetic environment this transition is split we have the nuclear Zemani gate here that work so if the iron in the material is exposed to a magnetic field in the magnetic material for example we get 6 dipolar out transitions here so compared to the 14.43 the transition these buildings are in the region of the nanoelectron I think that's good to play with a lot of energies here and unfortunately I picked out 3 of those here and 3 ray trains actually coming out here and what we observe is the far field the transition superposition of all these lines so 2 frequencies they could a more ray pattern with a signal frequency another frequency on top we get a more complex pattern and if we superpose all of them we get a temporal deep pattern like this here that is a metal one drum and iron metal foil and this is basically in this case of the magnetic structure of the subject so from this we can derive the magnitude of the magnetic fields and their direction in the material and so this has applications and not only managers in material science geophysics, chemistry, bio physics and so on so a magnitude of applications is possible and I have the pleasure to write this up some days ago I had an invitation to this from my field so that is actually the method and this is again the slide coming back to this now we have a great guide we have an atom we have iron 57 atoms and I have taken a wide use of these atoms without starting the interaction of these two level systems with the electromagnetic field inside of the cavity so there is a slide that I showed you before now we took the iron 57 atoms in there we do this with the deposition technology that I am also going to show you so let's point to this we prepared different cavities with ultrasonic interfaces with the requirement to make this work we need to put tools into the system and that is what we do with our labs at the end of the day at the end of the day now so that is a fine time of our deposition system at work so it is a chamber here I showed you that is the daytime in which you have to say we did a similar system in Vienna recently which is coming to work very soon and here is a inside room with a long axis of the cylindrical chamber I want to show you how such a process works looks actually at the start of the year it works so this factor moves along the axis and carries a sample which is actually shown here so here is the metal vapor from this other process from the room so we vaporize basically in the material discharge plasma so to say and the vapor is then propagated in the chamber where the sample is actually there the vapor is landing and forming into the room because by the total time and the control of the direction from which the atoms are landing on this heart by aligning the full line and assuming the angle of the sample relative to the impinging atom sets how we control the deposition process of these systems and this that we have developed over two decades basically we have been always in our papers as a set and we have also industrial applications and this is an information so we are coming from material science basically but we are also interested in fundamental applications and particularly the quantum optics of x-rays and yeah so let's now have a look and continue what happens if we put i-57 atoms in such a cavity so let's have a look at the single atom process yeah so the single atom or many of them if we look at the input here we have to analyze the energy distribution that we call a spectrum like this an energy spectrum like this this must be a spectrum for the single resonance single unit resonance of i-57 this might be many atoms but they all depend on the input here so we have an experimental distribution that is a width of 2.2 gamma naught that's a conversion electron spectrum so what happens now that we take many many atoms and form them into a layer which is now a projection of the layer inside of this cavity here so we decide the cavity for example the truss inside of the cavity here is maximum and what we measure is this spectrum we have to see a striking difference of two nodes that almost don't have to sway we have to see a programming and a normal programming and a shift of the center of gravity of this distribution this was done at the European Tick Collaboration Facility in 1918 and so people almost probably are shocked what happens is what we have here is actually we have to call it the reflected signal everything is going back and forth here and the partial waves that are coming out here that we call the energy in this setting all atoms from the blue in the same place scattering planes and the cavity in this way they radiate the eigenmode of the electron and this is something we have to believe in the radiative eigenmode you see from the fact that we have a variance in line shape here we just regard this here as an artifact we have this under control or relatively often we don't have it under control but we understand it where it comes from there is a good perfection some museums have a final reaction that leads to a deformation of the resonance line but this does not change the physics here so we have a variance here a very good approximation in line shape we can be sure that this is the radiative eigenmode we have it in so the bottom line of this slide is that a new optical phenomenon with atoms and pregnancies there is a information that implies the optical dimension of force and in the x-ray as well so the origin of these effects and now we come to some quantum optics in this case super gradients so when the situation that we encountered here the signal photon radiation source we have at most one photon per pulse the pulse source of the signal photon per pulse in the experiment this resonance in the x-ray with an analytical atoms chosen n equals to 5 so we have where we can have this, this, this or that we don't know which one that means we have to super close all these amplitudes here because all these configurations they take in the same finite state now so we have this situation we have the addition of one real photon so to say from that system here means that the collective decay is enhanced by a factor of 10 so the if you will drill in a bucket to sort of one hole in the pipe hole the bucket will empty 5 times faster than the signal hole I mean that is a classical signal and I know that quantum marketing applies also to the optics now so that's the physics that the particle has grown up already in the early of the last century and the particle is super real in this case we have a small sample limit, the large sample limit is a bit more complicated but this I cannot focus on here today however what I have shown here that applies also for the relativity physics here because compared to the standing way inside of the relativity this layer here is central to the central layer has a smaller extension of course than the spacing of this status of the limits that ensures the validity of the small sample limit of the super radians here that comes with it so in principle we have this enhancement of 65 and equals to 65 that means that effectively 65 atoms, resonant atoms were participating in the scattering process here on the bridge okay so so we have other lines here but yeah we have also workshop problems to consider in quantum optics right the virtual protons are the concept of this is actually at the basis of quantum electron and of course like another one in the famous experiment they identified in the shape of virtual protons that's the origin of this lump shape of the lifting of the degeneracy of 2.5 to 3.5 levels of hydrogen and this actually set the stage for how to achieve the virtual photons in the exchange with the exchange with the atom with the bound system set the stage for the right theory which turned out to be quantum electron dynamics in quantum days of course and this exchange of virtual photons led to yeah energy change of atomic levels as you know it's a sort of atomic self-energy correction and this applies also has also been taken into account that we have more than one atom interacting with the path of the virtual protons if we have say n-value atoms of course doesn't matter for the virtual protons if they are acting the same or the identity that happens in the vicinity so we have the cloud of identity that happens acting as a giant atom and we have to sum up more of these diagrams say at the first point so we have also a conclusion of a collective shift of the energy to itself and that was brought up by feedback and forwarders in the 70s of last century so that is actually the shift that we have applied to it that I have shown you before so we have two effects that happen that we have so we have an exchange of real and virtual protons so the real ones they enhance the width of the spectrum response and the virtual protons lead to a shift of this spectrum and that is actually what we have observed and this was for us published this in a journal that we have been taking our illustration on the cover here so I was just thinking it looks great that we visualized this and you all know if you put something between two parallel mirrors you have the barber shop or you put a bottle of wine and you apply it by one of the textures to mirrors that are here in parallel we get the search and the art director of science was decided by this and took it with him as a title here the title page and to this they wrote a perspective article on this emphasizing yeah another way how to summarize this everything we do is mainly the fundamental key effects to the radians of the collective function are magnified by collective active interactions between many atoms that is a good summary of this kind of physics and of course when we celebrate it we can open this bottle here and fill the glass and then we've got the next idea so why don't we put two more solvents two more things into the kit yeah inspire us eventually get to what we call now the 11 engineering so this is a transition to the next slide here maybe we have another that is now in the top order mode where I have three maxima in the top order mode and we have one ensemble in the center we start with and the bottle is here now we have the decalent bottle is here on the vertical axis and we have the ground state ground state has zero decalent it's an infinitely long lifetime of course and here we have the finite decalent for the ensemble here with anti-node and the maximum as we have shown as I have shown before we have a large line width which is a super radiant enhancement we measure this so it looks like this we measure the absorption on this transition here we measure this here for the sake of simplicity we make it to the lambshire but now we put the second ensemble into the decalent here we also have another nanometer or sub-nanometer thin layer here rolling into the node of the decalent cube that means that we are holding the entire state here which is much smaller than here so we can consider these ensembles here separated that means we came with a much smaller decalent width so we have this small gamma here in the node and then we have a coupling of these they are ready to make the cube of the cavity and so that we can have many many transitions here on this decalent cube which is a much smaller lifetime than this one here and we have many transitions mediated by the cavity field and this is actually the reason what we observed actually that is the phenomenon of deactivated induced transparency the interference of all these pathways from here to the excited state on the ground of the excited state which can go over and we can see involving this mid-stable state here the superposition of all these amplitudes with 0 at resonance that is the exact resonance where this would be completely opaque otherwise and that is EIT and we can do this interference the key phenomenon of quantum optics and that is what we essentially observed the experiment where we prepared such a system at a simple level and so that is actually another example of how these cavities can be used as a laboratory for quantum optics effectively to create a three-level system by properly putting the time of process atoms in two ensembles inside of the cavity and then we have as you know EIT observed slow life so to say how does this work I mean the second heat of the pier we use the absorption at resonance to 0 or almost 0 and that reveals that we can view with this present part which has a very steep slope here at the zero detuning and that means that the good velocity here which is 1 over the slope here of this part is very small and we have actually observed values of a few hundred meters per second inside of the cavity for the rest of radiation addressings another application would be for non-linearity because the first order or zero order with a perfection if it is cancelled then we would have access to the higher order to be the base of perfection but for the future that is not what we have done so far and I want to do one here with this little outlook on other applications so for the applications what we do how we move on is to enhance the metacoupling by putting many many cavities sort of on top of each other inside of such a modular structure so we can see that here and we also again look at the reflected signal and we selected the nuclear resonance scattering by the polarization filtering because nuclear resonance scattering is some extreme optical activity that we sigma to pi-stabbing that we can then filter out our polarization analyzer and we see here of the observed spectrum response shows a splitting of the line and over and the splitting will be plotted here as a function of the detuning of the radiation of that grand angle of this periodic structure shows a normal mode splitting that is a signature of collective storm coupling and the formation of the nuclear calamity that is another example of these layer structures of couple of cavities and this enabled us also to access the temporal resolved version of this storm coupling namely the arbor oscillations or sort of generalized arbor oscillations then the periodic energy that changed between these two 10 to 15 shear resonant energy that changed these arbor oscillations here and here again convincing the short visualization of the camera where this article was published so this is also a short view on another application that we measure and observe using these nuclear systems from the cavity to the magnetic cavity close to the storm collective coupling projects another recent application is to here along the axis of the wave guide where the collaboration is done where we have investigated what happens when radiation propagates inside of this layer where it has a front again inside of the guiding layer as a function of the propagation system we have here the sample where we can connect a certain propagation depth with this triangle and this sample see from the top to the picture here along the sample that we shipped this relative to the beam we can realize the propagation length and that's what we have done so here we can see saturation oscillation which affects the emission and absorption and absorption of the radiation inside of the cavity and so this of course is enhanced by the proper propagation distance and an even longer propagation distance so that is for the first time we have enhancement of the light matter coupling by just enlarging the propagation distance along the axis of the cavity and this is also recent which we learned from this year so that is still under the evaluation and we will see in a good way to be written up and so I want to move on this so far these examples were actually resulted in the spatial control of all the emission points now I come to the temporal control I think I speak this year how much time has to be 5 minutes 5 minutes so here we have control for example it's microwaves and we have a total way by inserting very short microwaves on the system and then really the temporal response in a very controlled way and here we have counter memory with a popular frequency comb that is we have utilized the frequency comb for the 17th year and frequency comb is nothing else but when this phase of realisation of different absorbers that are shifted in energy by euclidism these basements here so these are basically realised in a 7 iron-foils resonant absorbers on the liquid carbonic drives as they are used in the process with them so here we have 4, 1, 2, 3, 4, 5, 6, 7 in this address here and we as a result of this temporal this energy to the position where these EAs here on the temporal way that actually allows us then by changing the properties of this comb to tune and shift the spectral responses here of these peaks and control the emission of photons in this arrangement which is then or if quantum memory can store the quantum state of the quantum pulse shape of the incident program and release it in a controlled way at a later time that's also a work in progress here and in the last very last developments were this transition to single to multi-fogon excitation of the GI and what we had so far the experiments I have described so far are mainly single-fogons interacting at a given time with the osomal of the GI here so this method is basically established in 1985 and recently I'm sure we're always with very few photons of pulse that we obtain sufficiently many in our experiment is just to detect that the repetition rate of these sources is very high in megahertz so then we can still get enough photons actually through the experiment this situation probably would be the availability of X-ray lasers like the PX-ray in Hamburg probably a startup where we can have a concept that amplifies the mission radiation with several photons so that means we have access to new phenomena like exploring photon correlations coming into play we can even talk about creating non-classical states of X-ray life adding, as I said connected effects, like the resonance and so on many many photons at a time and so this is a short look at the evolution of the brilliance of these sources and leading to the development of X-ray lasers so there is a lot plot here of this evolution of the brilliance within these brilliance here irrelevant here as a number of photons per pulse over the years of the future so this was the life of the evolution of the cyclotron cyclotrons to use the parasitic node together with high energy for these applications dedicated once and up to all X-ray lasers and then one member of the European X-ray laser with the accelerations started the samples were in all the way to the coastline not all the way to Venmar but in the direction that means they are so as the current director of Venmar he is doing a very good job there so this is a two-pin with a long data structure here very impressive and almost the same length of the photon beam lines and eventually yeah so we did the first experiment with the resonance program at the European X-ray I have not the time to explain that here in detail I just wanted to show you the first temporal reading method we have recorded that actually could be explained theoretically with our tools that we have for describing this but we really need to simplify the discrepancy so the pitch here the simulation requires the assumption of the one micrometer thick foil of iron despite the fact that we have the fact that we have an 8 micrometer and we have a current with a 0.8 micrometer so there is a a lot of difference in the action of the resonance of torvus with the extremely intense light from the European from picture laser sources discrepancy that we have not resolved here so I think I leave this here as a last scientific style I have to move over to the other things that I intended to show you but I think that is too much I just want to move over to our summary so I will show you what is possible with the synchronous I will show you how these data recordings are to transport the perspectives I mentioned that open up the use of picture lasers just at the beginning we have to establish in the first films and currently I don't want to those without mentioning all my co-workers here which I have time to read and prove but to see all the institutions that are involved here and we are to be the the the the the the the the the the the And this is a new lab actually, we are moving in the next year, where we have already moved in some of our equipment, we are already there, and we are, yeah, it's kind of a vision there. We want more information just right here, otherwise, in any case, I would go to the slides. Okay, spoiler alert. Thanks. Thank you. That's all there was to it. You're welcome. Okay. Thank you. Okay. We'll see you next time. Bye. Thanks. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye. Bye.