Stimulated Thermal Scattering Induced by Two-Photon Absorption and Experimental Observation of the Genuine Stimulated Brillouin Scattering in the Near-Ultraviolet Region

Abstract

Part of the experimental measurements of the frequency shift and the phase-conjugation (PC) fidelity gained from previous studies of stimulated scattering (SS) of nanosecond ( ) near-ultraviolet (UV) ( ) laser pulses in liquids (hexane, heptane, and others) are found to disagree with the theory of SS, which takes into account only the linear (single-photon) light absorption. To resolve the inconsistency, SS of XeCl excimer laser radiation ( ) with the duration of in liquid hexane is investigated experimentally. A theoretical analysis of the results obtained revealed three new nonlinear optical phenomena induced by the heating due to two-photon absorption: stimulated thermal scattering (two-photon STS-2), phase mismatch for stimulated Brillouin scattering (SBS), and phase self-modulation. Experimental SS spectrum contains two new lines - a previously unknown two-photon STS-2 line and a genuine SBS line newly discovered in the near-UV region