Measurement of the Third-Order Nonlinear Optical Susceptibility \(\chi^{(3)}\) 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 σRS 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 σRS 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.