- How to interpret an ultrashort pulse and its interaction with matter in terms of photons and wavelength?
I am not understanding how to think of photons and wavelength in ultrafast optics. An ultrashort pulse is the summation of many wavelengths. So, if you refract an ultrafast pulse it will actually spread out spatially? Can you define a wavelength as sort of an average wavelength? And most of the applications are to do bio and materials measurements, so when it interacts with matter and you have to start thinking of it as photons, how does that make sense? Is it just nonlinear effects as it has to interact with many many photons at once? Or is it more useful to think of it as just an extremely high local electric field?