You can't get more direct than this in terms of proving that photons exist!
The particular case of the double-slit experiment will be discussed at: single particle double slit experiment.
Production:
Detectors are generally called photomultipliers:
Bibliography:
- iopscience.iop.org/book/978-0-7503-3063-3.pdf Quantum Mechanics in the Single Photon Laboratory by Waseem, Ilahi and Anwar (2020)
Rounds:
www.youtube.com/watch?v=v7iAqcFCTQQ shows their base technology:
- laser beam comes in
- input set via of optical ring resonators that form a squeezed state of light. Does not seem to rely on single photon production and detection experiments?