A convenient method to simulate and visually represent two-photon power spectra of arbitrarily and adaptively shaped broadband laser pulses

Abstract

We report a convenient model of second harmonic (SH) spectra resulting from shaped laser fields created in pixilated pulse shaping devices based on a matrix of all possible pair-wise, field interactions. This model is useful in estimating simultaneous two-photon absorption (TPA) and second harmonic generation (SHG) cross sections. A simple geometric interpretation of the model allows for a graphical representation of the SH spectrum as a set of vectors in the complex plane. This interpretation can be used to illustrate the effects of applied phase (and amplitude) shaping on second-order observables and it provides a facile explanation of the spectral focusing mechanism observed in numerous control problems. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.