KRAMERS-KRONIG RELATIONS IN NONLINEAR OPTICS

In the vicinity of the phase-matching angle of second-order nonlinear optical crystals, the fundamental light wave experiences an intensity-dependent phase shift which is connected with the effective attenuation due to second-harmonic generation. It is demonstrated that in the limit of weak pump depletion, the Kramers-Kronig relations can be used to derive a simple analytical expression for the phase shift as a function of the phase-mismatch angle. For certain mismatch angles, a large phase shift occurs without any attenuation.© 1995 American Institute of Physics.