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Absorption and refraction indices are the real and imaginary parts of the propagation constant for a medium. This means, given certain mild assumptions on the material's physics, they are the real and imaginary parts of a meromorphic (holomorphic with poles) function of the complex frequency that is holomorphic in the right half plane. They are therefore ...


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Given that most green pointers are frequency doubled from a 281.8 THz infrared laser ($c$/1064 nm), it's possible that you have a two frequencies $f_1$ and $f_2$ in the original infrared laser (i.e., it is multimode). After passing through the "frequency doubling" nonlinear crystal you see three frequencies: $2 f_1$, $2f_2$, and $f_1 + f_2$. It looks like ...


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The linewidths come out very naturally from Maxwell's Equations by treating the atom as a tiny classical antenna. I do the calculations for the 2p-1s transition in hydrogen on my blogsite here: The Semi-Classical Calculation The idea is that from the Schroedinger equation, the superposition of the s and p states gives you get a tiny oscillating dipole about ...


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The answer is yes, the atom does absorb radiation that does not exactly match the transistion frequency. This is due to the Doppler effect that everyone knows from an ambulance with siren driving by. The frequency you hear is higher if the ambulance moves towards you and lower if it drives away from you. It's the same with the atom. If the atom moves (and ...


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According to Bohr model, the absorption and emission lines should be infinitely narrow, because there is only one discrete value for the energy. There are few mechanism on broadening the line width - natural line width, Lorentz pressure broadening, Doppler broadening, Stark and Zeeman broadening etc. Only the first one isn't described in Bohr theory - it's ...



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