have you seen them? well now you have :3
Can a Human See a Single Photon? (1996)
31–40 of 142 posts
Re: Can a Human See a Single Photon? (1996)
#32It's amazing what happens in an eye: retinal (C₂₀H₂₈O), an aldehyde of Vitamin A, exists in two forms: all-trans-retinal gets hit by photos, flips and becomes 13-cis retinal (simplifying slightly). If enough photons are involved, the info gets transmitted to the train. If the photons were in a particular constellation, we see a "rectangle" or "circle"; quite a miracle if you think about it.
Re: Can a Human See a Single Photon? (1996)
#33I’ve been aware of this fact as Feynman points it out in the course of the lectures, but find it totally nuts — there is some sense of scale I’m missing. Matter consists of discrete chunks, atoms, but these chunks are so infinitesimal and numerous that there is no question of seeing them and any effect involving a handful of them is far, far below the human scale. Light also comes in chunks, and the number of these c…
Similarly surpising, large cities can be seen from orbit if you know where to look.
Re: Can a Human See a Single Photon? (1996)
#34On a related note, you can hear sounds that displace your eardrums on the order of an atomic diameter. At least that is something I heard years ago, a quick search turned up this StackExchange question [1] so there may be some truth to this, I did however not read the answers too carefully. They actually seems to suggest that the threshold is even quite a bit smaller which makes me somewhat cautious of the claim, but then again you are essentially integrating over really many atoms in your eardrum getting displaced together.
[1] https://physics.stackexchange.com/questions/147826/how-much-...
Re: Can a Human See a Single Photon? (1996)
#35Earlier quoted context omitted.
I do see exactly such a noise in dark rooms, am not unnerved by it at all.
Well that's expected when SNR is low. But in a dark room it's harder to see because SNR is low. I was just saying that I wouldn't want to artificially lower SNR in all environments, but maybe it wouldn't and maybe others do.
I think the noise is suppressed not merely because it's harder to see, but mainly because neural networks tend to hallucinate given such an input. In other words, there's fine tuning between losing weak signals and hallucinations.
Re: Can a Human See a Single Photon? (1996)
#36I’ve been aware of this fact as Feynman points it out in the course of the lectures, but find it totally nuts — there is some sense of scale I’m missing. Matter consists of discrete chunks, atoms, but these chunks are so infinitesimal and numerous that there is no question of seeing them and any effect involving a handful of them is far, far below the human scale. Light also comes in chunks, and the number of these c…
biological op-amps
Re: Can a Human See a Single Photon? (1996)
#37Earlier quoted context omitted.
Is this true or just a pun? Like your acid taste buds are literally sensitive enough to register a single H+ binding?
It is true you can taste protons. Whether you can taste a single one, I'm not sure, nor even how to test it. Fun video by Steve Mould on the subject: https://www.youtube.com/watch?v=FSYE1T5d9jc
I’m convinced you cannot taste single protons. Water self ionizes, so there will always be acidic species (H+, H3O+, …) way way above the concentration of single molecules.
Re: Can a Human See a Single Photon? (1996)
#38Recent experiments have put the claim to test Overview https://www.nature.com/articles/nature.2016.20282 The actual work https://www.nature.com/articles/ncomms12172 > Here we report that humans can detect a single-photon incident on the cornea with a probability significantly above chance.
Would be fun to see if it’s possible to set up the experiment as a double slit.
Would humans sense an interference pattern? Is the back of an eye a sufficient observer? :)
Re: Can a Human See a Single Photon? (1996)
#39What is the comparison to modern camera sensors nowadays? Can they detect single photons?
Yes, modern CMOS image sensors have quantum efficiencies of more than 80 %, and modern CCDs are well above 90 %. This depends on wave length, particularly in the NIR spectrum. This means that 80 or 90 % of the incident photons are converted into electrons. This number does not include photons being reflected from the surface of the sensor or the filter stack on top.
There's also SPADs "single photon avalanche diodes". These are sort of like a geiger counter for light, i.e. a single interacting photon triggers an impulse that can be counted or timed. These are very commonly used for time-of-flight sensors.
Re: Can a Human See a Single Photon? (1996)
#40Genuine question: I’ve never taken LSD, but could some of its purported visual effects be explained as seeing photons via a depressed neurological filter?