SpectRal-Crystal Efficiency-Mapping (SCEM): A Powerful Analytical Tool for modElling Quasi-Phase-Matched Interactions

The conventional approach to calculating quasi-phase-matching (QPM) gain stems from three coupled wave equations [1], which fail to account for frequency-dependent nonlinearities or real pump pulses with non-zero linewidth. These deficiencies limit the method's accuracy and applicability, particularly in applications employing broad bandwidth pulses or requiring precise control over frequency conversion processes. Here, we demonstrate a method for more complete analysis of the phase-matching potential resulting from combining one or more input spectra and a nonlinear crystal, with results which can be easily interpreted by means of a spectral-crystal efficiency-map (SCEM). This analytical approach agrees strongly with more computationally demanding full-field numerical simulations [2], and predicts the maximum power one can expect from real frequency conversion processes.