Investigation of nonlinear dynamics in CdS by time-resolved nondegenerate pump–probe system with phase object

Abstract

The time-resolved nondegenerate pump–probe system with phase object is employed for investigation of nonlinear absorption and refraction dynamics in CdS. The 532 nm laser beam with 21 ps duration is used as the excitation and the laser beams of 600 and 680 nm with 10 ps duration from optical parametric generation are used for probing. The experimental results at both probe wavelengths show free-carrier absorption and large free-carrier refraction along with two-photon absorption and bound electronic optical Kerr effect. By numerically fitting the experimental data based on the nondegenerate pump–probe theory, the nondegenerate two-photon absorption coefficient, the nondegenerate Kerr coefficient, the free-carrier decay time, the free-carrier absorptive cross-section and free-carrier refractive coefficient at different wavelengths are all determined.

Keywords:

• nondegenerate
• dynamics
• free-carrier refraction
• two-photon absorption

Acknowledgements

We acknowledge support from the Ministry of Science and Technology of China for the International Collaboration on Scientific Research (2009DFA50620).