Tutorial Photon Optics

[Music] okay good morning welcome to introduction to photonics so far we've been actually looking at properties of photons in terms of the photon energy looking at photon momentum what does it mean to what is the probability of finding a photon at a particular location and related to that we were also looking at photon uncertainty so

what I would like to do today is you know just see if we can gather all the things that we learned and see if we can solve problems okay related to photon optics so let's take the example of example let's say 1a right so you are told that you have a CW laser right you

have a CW laser so what does CW mean CW is corresponding to continuous wave okay as opposed to the other type of laser which would be like a pulse laser okay so if it's emitting pulse laser then the pulses if you say it's as a pulse laser ways it's a continuous wave laser

of course we will find that it's actually sort of a misnomer because we talk about continuous wave as in continuously propagating as waves but what we are actually going to look at is the photon properties of this laser photon emitting properties of this laser so you are told that this continuous-wave laser has a wavelength

of 0.2 microns and it's emitting radiation which corresponds to one nano watt of power okay now what you are asked to figure out is if you if you put a detector over here then what is the rate at which photons fall on the detector so what is the rate at which photons fall

on the detector is what you you are asked to figure out so what we see is in conventional wave optics you deal with quantities in terms of power energy energy density power density which is intensity and and so on and what we will see in the corresponding photon picture is we will talk about number of photons