Now I can obviously just search the internet for information about what these areas of physics are about, but what I want to know is more specific information about these areas that I can't find. Like what areas of Physics are used in Optical physics or maybe more specifically Quantum Optics/Information, besides the obvious thing like optics. Electrodynamics, and Quamtum mechanics are when talking about Quantum Optics, what about areas like QED, or maybe QTF? Are they 'useless' in optical physics? So to be even more specific what areas of math do one also use? Since I want to take some math courses, and don't want to take stuff completly irrevant. And the questions for Solid State Physics.