Raman induced phase conjugation spectroscopy

Abstract

Raman induced phase conjugation (RIPC) spectroscopy is a relatively new coherent Raman spectroscopic (CRS) technique using optical phase conjugation (OPC), with which complete Raman spectra of transparent media can be obtained. It is a non-degenerate four-wave mixing technique in which two pulsed laser beams at Ω₁ and Ω₁ ± Δ where A corresponds to a vibrational frequency of a nonlinear medium mix with a third laser beam at Ω₁ to generate a fourth beam Ω₁ ± Δ, which is nearly phase conjugate to one of the beams at Ω₁. With this technique one can measure the ratio of the resonant and nonresonant components of the third-order nonlinear susceptibilities of the nonlinear media. We have used this technique to get Raman spectra of well-known organic solvents like benzene etc., using pulsed Nd: YAG -dye laser systems. We have also studied the effect of delaying one of the interacting beams with respect to the others and the phase conjugate property of RIPC signals.