Since I put a few notes on Geometric Optics on this site, from time to time viewers have written to me asking if I am going to write some notes on Physical Optics. The answer has always been that I was not planning to. However I have scribbled one or two notes on isolated and random topics, and I present them here. I am nowhere close to getting together a full course on Physics Optics, so for the time being I give some notes on the following random small topics. Any further topics may appear if and when the spirit moves me, at a rate of maybe one new topic every few years. I hope the following are of some interest.