5 ms·
Double-slit time diffraction at optical frequencies
- lawrenceyan 4y agoWould this experiment still have worked if the time differential between the two time slits was longer?
- Eddy_Viscosity2 4y agoThis is a slightly off topic question but commenters here might have an answer. In the original double slit experiment, how do they actually know that they are emitting a just a single photon. The entire experiment depends on this being the case, but how is it done? Especially way back when it was first performed. How could they confidently say that have an apparatus that can reliably only emit a single photon, yet at the same not be clear about whether light was a wave or a particle.
- skzv 4y agoThe original experiment did not rely on the emission of individual photons. It just observed an interference pattern that classical particles would not exhibit. Later experiments that relied on individual photons could detect them individually [0] Here's an article on single photon sources [1] [0](https://en.wikipedia.org/wiki/Double-slit_experiment#/media/File:Wave-particle_duality.gif https://en.wikipedia.org/wiki/Double-slit_experiment#/media/...) [1](https://en.wikipedia.org/wiki/Single-photon_source https://en.wikipedia.org/wiki/Single-photon_source)
- ssgh 4y agohttps://arxiv.org/abs/2206.04362 https://arxiv.org/abs/2206.04362 [Submitted on 9 Jun 2022 (v1), last revised 16 Jun 2022 (this version, v2)]
- ynniv 4y agoSurprisingly, many more oscillations are visible than expected from existing theory This is the best part of science
- troymc 4y ago"The most exciting phrase to hear in science, the one that heralds new discoveries, is not “Eureka” but “That’s funny...” —Isaac Asimov
- anonymouskimmer 4y agoWith engineering it's the opposite way around. So if you hear a STEM person say either, ask what their job is.
- zwieback 4y agoSo true. As engineers we take all the art and some of the science out to make things super predictable.
- notdang 4y agoBecause of parallel universes?
- changoplatanero 4y agoSomeone who understands it better care to explain what this would look like? I can't open the article so I can't tell if there are any pictures.
- slrainka 4y agohttps://arxiv.org/pdf/2206.04362.pdf https://arxiv.org/pdf/2206.04362.pdf
- mrandish 4y agoAbstract The wave nature of light is revealed by diffraction from physical structures. We report a time- domain version of the classic Young’s double-slit experiment: a beam of light twice gated in time produces an interference in the frequency spectrum. The 'time slits', narrow enough to produce diffraction at optical frequencies, are generated from a thin film of Indium-Tin-Oxide illuminated with high-power infrared pulses, inducing a fast reflectivity rise, followed by a slower decay. Separation between the time slits determines the period of oscillations in the frequency spectrum, while the decay of fringe visibility in frequency reveals the shape of the time slits. Here we find a surprise: many more oscillations are visible than expected from existing theory, implying a rise time for the leading edge of around 1-10 fs, approaching an optical cycle of 4.4 fs. This is over an order of magnitude faster than the width of the pump and can be inferred from the decay of the frequency oscillations. ... In conclusion, we report a direct observation of spectral oscillations, at optical frequencies, resulting from double-slit time diffraction, the temporal analogue of the Young’s slits experiment. The measurements show a clear inverse proportionality between the oscillation period and the time slit separation. These oscillations reveal a 1-10 fs temporal dynamics of the ITO/Au bilayer, much faster than previously thought and beyond the adiabatic and linear intensity dependence assumed so far in most theoretical models (10)(11),(17), calling for a new fundamental understanding of such ultrafast non-equilibrium responses. The observation of temporal Young’s double-slit diffraction paves the way for optical realizations of time- varying metamaterials, promising enhanced wave functionalities such as nonreciprocity (18), new forms of gain (19)(20), time reversal (21)(22) and optical Floquet topology (23)(24). Double-slit time diffraction could be extended to other wave domains, e.g. matter waves (6), optomechanics (25) and acoustics (26)(27), electronics (28), and spintronics (29), with applications for pulse shaping, signal processing and neuromorphic computation. Finally, the visibility of the oscillations can be used to measure the phase coherence of the wave interacting with it, similarly to matter-wave interferometers (6).
- UncleOxidant 4y agotime reversal?
- teraflop 4y ago
- davnicwil 4y agoWhat do they mean by time slits? A beam of light twice gated in time... what does this mean? Is it something like sending pulses of light towards each other separated by some very small amount of time and observing an interference pattern of some kind?
- armchairhacker 4y agoI believe it's like a filter which briefly lets light pass through, twice, although the way they achieve this is weird. In conventional double-slit the 2 splits have different x positions, here they have different t positions. The diagram of page 3 of this helped me understand: https://arxiv.org/ftp/arxiv/papers/2206/2206.04362.pdf https://arxiv.org/ftp/arxiv/papers/2206/2206.04362.pdf.
- totetsu 4y agoSo like a rolling shutter?
- bb88 4y agoA rolling shutter doesn't cause changes in frequency of the light itself. The temporal slit appears to be causing frequency changes in the light beam. These frequency changes then interfere with each other creating a diffraction in the spectral frequency (rather than by physical distance as is with the traditional double slit experiment).
- MayeulC 4y agoIt also sounds a lot like a phased array antenna from the descriptions in this thread.
- deleted 4y ago[deleted]
- dkural 4y agoThis seems like a relevant write-up from a Nature science reporter: https://www.nature.com/articles/d41586-023-00968-4 https://www.nature.com/articles/d41586-023-00968-4
- airstrike 4y ago> “This can bring about more applications, for example novel antennas for 6G, using time to combine many antennas in one.” I was hoping for time travel or, at a minimum, reversible computing, but I guess I'll settle for faster streaming of cat videos
- KRAKRISMOTT 4y agoSo a time domain meta-material?
- riedel 4y agoI think the nature author thought the same thing and then added a sentence at the very end, which sums up the rest they did not quite grasp (like me) and sound more like Dr. Who: >Temporal interference and time reversal could lead to new ways of creating time crystals, which are mind-bending structures that repeat periodically, not in space — as ordinary crystals do — but in time. They could also help researchers build quantum computers based on photons.
- savrajsingh 4y agoTwo fermilab videos on the double-slit experiment. Looking forward to their explanation of this paper as well https://www.youtube.com/watch?v=nmxwVU88Bd8 https://www.youtube.com/watch?v=nmxwVU88Bd8 https://www.youtube.com/watch?v=l8gQ5GNk16s https://www.youtube.com/watch?v=l8gQ5GNk16s
- whatshisface 4y agoYou can do this with sound if you clap twice and make a spectrogram.
- Nevermark 4y agoThat would be the classical analogue. But it doesn’t capture what makes the quantum version of the experiment interesting. Which is that if you only have one clap, but at two possible times, you will detect (“hear”) the clap at only one location each time. But the chance you hear the clap at any given position is based on where that position is in the wave you might expect if there had been two classical claps. I.e. the quantum surprise is single particles interfere with themselves across the alternate paths they could take, not just each other. Or in this case, interfere with themselves across two alternate times they could take on the same path.
- mathematicaster 4y ago> Or in this case, interfere with themselves across two alternate times they could take on the same path. This is gold.
- guepe 4y agoMy quantum physics classes are far back and that explanation nailed it for for me.
- pixel_tracing 4y agoCan someone please ELI5? Where is ChatGPT when you need it
- nine_k 4y agoHere's to best of my understanding. Space and time in general relativity are but inseparable axes of the same spacetime. But, unlike completely interchangeable and real space axes (e.g. "length, width. depth"), the time axis is slightly special: it's counted as imaginary (see Minkowski space: the distance contracts along the time axis). But otherwise it's an axis like width of height or length. Quantum "particles" are also "waves", that is, they behave a bit like both, but not exactly like your normal grains of sand or water waves. Like particles, they are "separate", so you can count electrons or photons, and can't cut them in half Like waves, they are wavy and fuzzy, without a sharp edge or border, and interact like waves. When one wave's hump meets another wave's trough, they cancel out ("destructive interference"). When two humps meet, they reinforce each other, resulting in a bigger hump ("constructive interference", yes, sounds ironic). This is easy to imagine in the space domain, with normal waves that go, say, "up" and "down". With experiments with photons the waves represent the strength of the electromagnetic field, and the interference pictures are ring-like. Now replace one of the dimensions of the ring with time. This will mean that instead of e.g. darker / brighter circles or stripes on the picture, you will detect "bands" or "stripes" of higher / lower intensity spread over time. Intensity changing over time is oscillation. E.g. air pressure oscillating over time is sound. Electromagnetic field oscillating over time is radiation: radio waves, light, x-rays, etc. So the experiment managed to let two photons through "slits" in time rather than in space, by opening a "hole" for them to pass and then closing it back really quickly, so that two photons would pass the opening really close in time to each other. This is similar to how the typical double-slit experiment puts slits (or holes) really close by in space, so that the photons can't be far away from each other while interacting. Then they registered the interference picture, which, AFAICT, was a burst of various electromagnetic frequencies (a "spectrum"). Each photon has a very well-defined frequency (or wavelength, or color, for visible light). So seeing a variety of different frequencies ("colors") would be a tell-tale sign that interference happened, producing multiple "stripes" in the time domain, not space domain.
- vrglvrglvrgl 4y ago[dead]
- aj7 4y agoOptical Ramsey fringes are not this?
- eis 4y agoWith the classic double slit experiment both space coordinates affect each other. With this time axis double slit experiment one has to ask if t1 affects t2 or if t2 also affects t1. The latter would raise a lot of questions. I don't understand the paper well enough to know which of these cases they are observing but I assume only the t1->t2 case? I'd appreciate if someone with more domain knowledge could enlighten. Edit: after more thought I guess it would make sense that two slits after each other in time show a change in wavelength if they are brought close enough together. Essentially the time separated slits act like a space separated double slit experiment wherin the slits are oriented on an axis parallel to the direction of the light path instead of at a perpendicular one. The wave like nature does not just expand in one dimension in space but all three and so there must be interference in the direction of travel. Do I have the right idea with this?
- deleted 4y ago[deleted]