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.

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·s² 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 cm² 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·s² for the resonant component of 3χ⁽³⁾. A value of 1.9 ± 0.9 × 10^-12 cm·g^-1·s² has been deduced for the nonresonant component of 3χ⁽³⁾. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]