Measurement of the third-order nonlinear optical susceptibility χ ~(3) for the 1002-cm ~(-1) mode of benzenethiol using coherent anti-Stokes Raman scattering with continuous-wave diode lasers

摘要

The components of the third-order nonlinear optical susceptibility χ ~(3) for the 1002-cm ~(-1) mode of neat benzenethiol have been measured using coherent anti-Stokes Raman scattering with continuous-wave diode pump and Stokes lasers at 785.0 and 852.0 nm, respectively. Values of 2.8 ± 0.3 × 10 ~(-12), 2.0 ± 0.2 × 10 ~(-12), and 0.8 ± 0.1 × 10 ~(-12) cm·g ~(-1)·s ~2 were measured for the xxxx, xxyy, and xyyx components of |3χ ~(3)|, respectively. We have calculated these quantities using a microscopic model, reproducing the same qualitative trend. The Raman cross-section σ _(RS) for the 1002-cm ~(-1) mode of neat benzenethiol has been determined to be 3.1 ± 0.6 × 10 ~(-29) cm ~2 per molecule. The polarization of the anti-Stokes Raman scattering was found to be parallel to that of the pump laser, which implies negligible depolarization. The Raman linewidth (full-width at half-maximum) Γ was determined to be 2.4 ± 0.3 cm ~(-1) using normal Stokes Raman scattering. The measured values of σ RS and Γ yield a value of 2.1 ± 0.4 × 10 ~(-12) cm·g ~(-1)·s ~2 for the resonant component of 3χ ~(3). A value of 1.9 ± 0.9 × 10 ~(-12) cm·g ~(-1)·s ~2 has been deduced for the nonresonant component of 3χ ~(3).