Multiple stokes and anti-stokes generation in triclinic γ-KIO{SUB}3 and hexagonal α-LiIO{SUB}3 crystals

摘要

The high x{sup}(2) and x{sup}(3) nonlinear properties of acentric iodates with molecular structure in the form of trigonal pyramidal (IO{sub}3){sup}- groups have attracted much research attention during the last several decades. In particular, single crystals of α-LiIO{sub}3 and α-HIO{sub}3 have been investigated for second harmonic generation (SHG) and stimulated Raman scattering (SRS) processes, including different effects of parametric processes. In the case of γ-KIO{sub}3, the principal barrier to its detailed characterization has been the difficulty in growing large single domain crystals of optical quality. Recent progress in crystal growth techniques for γ-KIO{sub}3 has produced cm-long crystals appropriate for optical measurements. In this paper, we report on the first experimental demonstration of high-order Stokes and anti-Stokes generation in triclinic γ-KIO{sub}3 crystals by cascading SRS and Raman-induced four-wave mixing (RFWM) under picosecond laser excitation at room temperature (RT) in the visible and near infrared (NIR). We also present some new data on multiple SRS in α-LiIO{sub}3 crystals.