Photon Properties

[Music] okay welcome to yet another session of introduction to photonics during the last couple of sessions we'd been trying to get into this learning outcome of identifying the fundamental principles of photon optics and quantifying photon properties and to understand that it was essential that we introduce light as electromagnetic waves so if I go back

and look at where we all where we started this all you know ray optics wave optics and last couple of lectures we've been looking at light propagation as electromagnetic waves now what we will do for today's session is actually consider light to be propagating as particles okay these quantized electromagnetic waves that are known as

photons okay so let's try to see what this is all about the the basis for a lot of this discussion came about when Max Planck was conducting his research that was to solve this problem of blackbody radiation when I say blackbody radiation what comes to your mind what is blackbody radiation I can give

an example of blackbody radiation the black holes more simply the light from the stars the closest star that we have Sun so when we are looking at Suns radiation we can consider that as blackbody radiation so Planck was actually looking at blackbody radiation and around 1900 when he was trying to explain blackbody

radiation he figured that light must be emitted as or this blackbody radiation must be coming out as quantized electromagnetic waves so essentially he was figuring that light is emitted when an atom or more specifically an electron actually jumps from a higher energy level to a lower energy level when that happens he said you have this quantized