Explanation of the competition between O- and E-wave induced stimulated Raman and supercontinuum in calcite under ultrafast laser excitation

Shah Faisal B Mazhar; Henry J Meyer; Tyler Samuels; Mikhail Sharonov; Lingyan Shi; Robert R Alfano

doi:10.1364/AO.393932

Explanation of the competition between O- and E-wave induced stimulated Raman and supercontinuum in calcite under ultrafast laser excitation

Appl Opt. 2020 Jun 10;59(17):5252-5257. doi: 10.1364/AO.393932.

Authors

Shah Faisal B Mazhar, Henry J Meyer, Tyler Samuels, Mikhail Sharonov, Lingyan Shi, Robert R Alfano

PMID: 32543546
DOI: 10.1364/AO.393932

Abstract

Key optical properties of calcite were measured to unravel the difference between stimulated Raman scattering (SRS) and self-phase modulation (SPM) for the supercontinuum (SC) for ordinary (O) wave and extraordinary (E) wave. These properties are group velocity dispersion, walk-off, spontaneous Raman spectra and cross section, optical 1086cm^-1 phonon linewidth, nonlinear susceptibility (χ³), steady-state and transient SRS, and SC caused from SPM. These are investigated for O-waves and E-waves from a 2.7 cm thick calcite crystal. Using 390 fs pulses (∼0.8µJ pulse energy) at 517 nm, the O-wave produced a stronger sharp SRS peak at 1086cm^-1 and a weaker SC spectrum in the visible range than the E-wave. The salient difference found between the O- and E-waves for SRS and SPM in calcite is attributed to the larger Raman cross section and the size of nonlinear susceptibility (χ³) for O-waves as compared to E-waves.