Xjyuk

As part of a course in physics teaching, I am developing a small curriculum that will teach (the basics of) quantum mechanics to high school students.

I need a simple way to show the quantization of light. My uni lecturer suggested that low-light photography shows grainy pictures because of individual photons hitting the sensors in discrete points, which shows that they are not diffuse waves.

I have been unable to find anything confirming this on the internet, much less a picture or even better video showing the effect.

I suppose I'm looking for something similar to this video of Tonomura's experiment on the quantization of electrons.

Thank you for your time.

EDIT: I am not actually looking for the equipment. Mere footage of the equipment would be more than adequate. (Just like I won't try to replicate Tonomura in a classroom, but I will show its video)

There are a number of videos online of optical interference patterns being built up at the level of single photons. For instance there is this short YouTube video taken in 2008 at Leiden University using an intensified CCD or ICCD camera (essentially a CCD with a phospher screen that is sensitive at the single photon level). As described in the details on the YouTube page:

This movie has been captured with an intensified CCD camera. The movie consists of 200 frames, with exposure times ranging between 0,025 milliseconds and 6,000 milliseconds. It shows how individual photons, transmitted through a double slit, form an interference pattern. It shows wave-particle duality of light.

There is also a much longer video on YouTube here, but there is no information on where this video was taken or any of the parameters used.

If you are looking for a source that gives a more in-depth explanation of how you might actually do these types of experiments (including still images of actual experimental resutls), I recommend something along the lines of this 14 minute lecture by Alain Aspect. A screenshot of one of the experimental result slides from this video is shown below

Film with silver halide grains is a bit old fashioned, also slow (you need to develop the film).

A photon-counting image sensor would be clearer, but more expensive. This is research: https://www.laserfocusworld.com/test-measurement/research/article/16555293/advances-in-detectors-the-quanta-image-sensor-qis-making-every-photon-count

Amateur astronomers might have something.

Silver halide film doesn't really respond to single photons; it takes four photons, absorbed within a short period of time, to expose a silver halide crystal in the film. An imaging photomultiplier or other photon-counting image sensor would be better, as @Pieter pointed out.

I doubt if there are cheap and quick solutions - photomultipliers usually cost $1000 or more.

@Pieter mentioned amateur astronomers, and I guess what they do is use cooled CCD or CMOS sensors for imaging in an extremely low-light, extremely long-exposure condition (and this is the condition you would need to demonstrate the grainy images of photons eventually smoothening). At room temperature, the dark noise of typical camera is too high, and that is why you need to cool the sensors to very low temperatures (~ -50 C or lower) using things like thermoelectric coolers (TEC) or Peltier coolers (and you will need some vacuum around your cooled sensor to avoid condensation).

There are some online tutorials on modifying consumer-grade DSLR cameras to Peltier-cooled cameras suitable for astro-photography. But DSLR cameras themselves are not cheap, and there is a lot of modification going on, so again this is not a cheap and quick solution.

As a side note, if your camera sensor is not good, it will have a poor read-out noise, and your image noise will be dominated by electron noise from reading-out procedure instead of the shot noise of your light, even when you have eliminated the problem of hot thermal electrons. But if your camera supports hardware binning of multiple pixels, you can circumvent that problem.