Stimulated Raman scattering signal amplification in ethanol molecules via resonant cascading

Abstract

Lowering threshold and enhancing intensity of stimulated Raman scattering (SRS) have been a major focus of nonlinear optics. In our experiments, we combined SRS generation and amplification techniques to enhance the SRS signal. The amplification was achieved through a process called resonance effect, where the frequency difference between the pump laser and the Stokes light emitted from the working medium had self-matched with the vibrational energy level. The performance improvements included a higher SRS conversion efficiency, reaching up to 5.31%, approximately three times the value of a single sample cell efficiency of 1.739%, and realization of a cascaded SRS up to four orders extending from 461 to 997\u2009nm. These Stokes and anti-Stokes coherent lights were generated coaxially to the pump beam as axial and conical ring beams, respectively, which can be explained by the four-wave mixing. This technique has the potential to contribute to the development of a multi-wavelength cascade Raman laser.