PMT2: Photon Bunching / Hanbury Brown & Twiss effect

Video Description

This is the second video about photomultipliers and their use. In this video I set out to measure an effect called "Photon Bunching". Photon bunching is phenomenon characteristic for incoherent light It can for example be used to measure the angular diameter of stars and was discovered by Robert Hanbury Brown and Richard Quintin Twiss in 1954. Video chapters: 0:00 Introduction 0:42 Brief description of coherence 4:01 Description of the experimental setup 10:17 Aim of the experiment 11:40 Main result 12:25 Explanation and discussion 13:10 What is a photon? 16:10 Relation field amplitude / intensity / probability 22:17 Second order correlation function described 25:23 The Hanbury Brown & Twiss effect 27:25 Trying to measure g(2); failure and succss All wave animations in this video were produced using a Python script supplied by @DiffractionLimited . Thank you very much Manuel for supplying me with this tool. https://github.com/0x23/WaveSimulator2D There is a typo in the second order correlation function formula presented at 22:25: The denominator should contain the square of the time averaged intensity instead of the time average of the intensity squared. SigView Spectra Analysis Software: https://www.sigview.com/ (I have no commercial affiliation, it's just great software) Third party imagery and clips: 14:35 Image standard Model of elementary particles: Source WIkipedia 14:55 I got the "face slap" clip of a channel named @neilsandwichtv5186. Not sure if this channel indeed is the copyright owner. Contact me if you have more info on this. 13:36 I used a few very short clips from @ArvinAsh as illustrations of the particle presentation of light and photons. Arvin makes very high quality content on various scientific subject. But I guess his photon visualizations leave some room for improvement (;-). Did I forget something? Let me know and I'll set it straight. Music used : "Floating" (personal composition) performed by the Early Birds (1999).