Microscopic calculation of surface-induced second-harmonic generation in crystals of para-nitroaniline

Abstract

Previous results for surface linear optical response in centrosymmetric para-nitroaniline crystals are combined with literature values for the molecular first hyperpolarizability to calculate the surface-induced quadratic response. The average surface quadratic susceptibilities for incident light at a wavelength of 803 nm are calculated to be 71 and 50×10−22 m2 V−1 for different surface terminations normal to the [001] direction, and 9 and 7×10−22 m2 V−1 for different surface terminations normal to the [101] direction (the natural cleavage plane). The latter values are three orders-of-magnitude below that determined by Kobayashi and Kotani, consistent with their evidence for bulk second-harmonic generation from a new phase at the surface.