Breakdown of the slowly-varying-amplitude approximation: generation of backward-traveling, second-harmonic light

J. Z. Sanborn, C. Hellings, T. D. Donnelly
2003 Journal of the Optical Society of America. B, Optical physics  
By numerically solving the nonlinear field equations, we simulate second-harmonic generation by laser pulses within a nonlinear medium without making the usual slowly-varying-amplitude approximation, an approximation which may fail when laser pulses of moderate intensity or ultrashort duration are used to drive a nonlinear process. Under these conditions we show that a backward-traveling, second-harmonic wave is created, and that the magnitude of this wave is indicative of the breakdown of the
more » ... lowly-varying-amplitude approximation. Conditions necessary for experimental detection of this wave are discussed.
doi:10.1364/josab.20.000152 fatcat:xonhj2alxrcs3k2rzlmoduycka