Multi-wavelength quasi-continuous wave all-solid-state system based on Raman lasers

Abstract

ABSTRACT High-repetition-pulse-rate nanosecond laser system is developed. It is based on Raman lasers with barium nitrate and KGW crystals. The minimum Raman threshold of laser generation corresponds to only 0.2-0.4 kW of peak pumping power. The laser system generates the radiation at 22 wavelengths in the 280-1600 nm spectral range with average powers from several mW to 1.4 W. The maximum Raman conv ersion efficiency reaches 40 %. The minimum spectral width of the generated radiation is equal to 0.1 cm -1 . This laser system can be used for spectroscopy studies, medicine, and for other applications. Keywords: Raman laser, crystal, quasi-continuous wave radiation, the Stokes component, efficiency 1. INTRODUCTION Lasers based on stimulated Raman scattering (SRS) of light (Raman lasers) in crystals are promising solid-state sources of radiation in a wide spectral region 1, 2 . In the last time, the main aims of optimizing such lasers are reaching their efficient generation in new regimes such as quasi-continuous wave (quasi-CW) generation regime, when the pulse repetition rate is equal to 1 kHz or higher, and continuous wave (CW) regime of generation, and widening the spectral range of the generated radiation wavelengths. Besides, many physical phenomena which effect to the Raman laser operation are not comprehensively studied yet. These are ther mal lensing, Raman beam cleanup, influence of the spectral bandwidth of the pumping radiation, nonlinear refraction and absorption. In this paper, we present the results of our studies on deve lopment of a comparatively cheap and simple in use quasi-CW laser system based on crystalline Raman lasers. It efficiently generates multi-wavelength radiation from the ultraviolet (UV) to near infrared (IR) spectral range.