Nonlinear optical characteristics of carbon disulfide

The nonlinear refractive index γ of CS2 is studied using laser pulses of various durations (from 110 fs to 75 ns). It is found that γ increases with increasing pulse duration within the picosecond region (from (3 ± 0.6) × 10−15 cm2 W−1 at 110 fs to (3.5 ± 0.7) × 10−14 cm2 W−1 at 75 ns) due to orientational nonlinearities. Variations in the sign of γ caused by the thermal effect at different pulse durations and repetition rates are analyzed. It is demonstrated that the fast electronic component, the component associated with molecular processes, causing positive nonlinear refraction, and the acoustic component, responsible for negative nonlinear refraction, manifest themselves simultaneously. The results of a study of the nonlinear absorption of carbon disulfide are presented. The two-and three-photon absorption coefficients of CS2 are determined to be (5 ± 1.5) × 10−11 cm W−1 and (2.8 ± 0.8) × 10−23 cm3 W−2, respectively.