The QED experiments Feynman describes in his Auckland lectures on Vega website

[roberto85]

Hi all, I am looking for some more information about the experiments that Feynman describes during the lectures that he gave in Auckland which can be viewed on the vega science trust website. The first experiment is where photons are transmitted or reflected by one surface with a second similar surface beyond the first and it shows varying rates of trasnmission/reflection depending on the distance between the two surfaces. Is there a particular name given to this experiment or can anyone point me to some information concerning it please?

He also describes some experiments with polaroid sheets but i haven't reached that video yet and i have questions about that particular one, so i will post about it later. I had first seen these lectures the year before i began my physics degree and now 5 years later I am watching them again to refresh my memory. Many thanks

Roberto85

 

[jtbell]

The first experiment is where photons are transmitted or reflected by one surface with a second similar surface beyond the first and it shows varying rates of trasnmission/reflection depending on the distance between the two surfaces. Is there a particular name given to this experiment or can anyone point me to some information concerning it please?

It's called "thin film interference."

http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/thinfilm.html

This is a purely classical treatment. I haven't seen the video that you referred to, so I don't know how Feynman connects it with QED. As far as I know the QED results are the same as the classical ones, except that instead of "intensity" or "brightness" of the reflected or transmitted light, in QED they describe the probability of a single photon being reflected or transmittted.