near the mark, or is it a different process entirely?
(From: Doug McDonald (mcdonald@scs.uiuc.edu).) This is correct. (From: Martin.) If my guess is anything like correct, it would seem valid to predict that the doubling should not be particularly frequency-specific, so one should be able to use the crystal to double (or triple, etc.) any visible/IR/UV wavelength more or less equally. Yet, I have not heard of this being done. I have not heard of doubling the output of an 808nm pump diode directly (without YAG, etc.) to get UV. This suggests to me that there is strong wavelength-dependence. If so, why? (From: Doug.) Now the tricky part. You are thinking like radio frequencies. At readio frequencies, the non-linear element (e.g. diode) is small compared to a wavelength. At optical frequencies it is not. Consider a yagi antenna that has each element nonlinear. It won’t work for the second harmonic at all, and will have a vastly different spatial pattern for the third harmonic. The point is that the non-linear signals from different parts of
(From: Doug McDonald (mcdonald@scs.uiuc.edu).) This is correct. (From: Martin.) If my guess is anything like correct, it would seem valid to predict that the doubling should not be particularly frequency-specific, so one should be able to use the crystal to double (or triple, etc.) any visible/IR/UV wavelength more or less equally. Yet, I have not heard of this being done. I have not heard of doubling the output of an 808nm pump diode directly (without YAG, etc.) to get UV. This suggests to me that there is strong wavelength-dependence. If so, why? (From: Doug.) Now the tricky part. You are thinking like radio frequencies. At readio frequencies, the non-linear element (e.g. diode) is small compared to a wavelength. At optical frequencies it is not. Consider a yagi antenna that has each element nonlinear. It won’t work for the second harmonic at all, and will have a vastly different spatial pattern for the third harmonic. The point is that the non-linear signals from different parts of
