A Continuous Wave Raman Laser to Access a Broad Spectral Regime

Abstract

Abstract : The purpose of this work was to explore the continuous wave (cw) Raman laser for generating high-power laser radiation in the Infra-Red (IR) spectral regime. This was done by numerically modeling cw Raman lasers. The numerical models were compared with results from recent experiments to confirm their accuracy. A survey was conducted to identify necessary components for this technology, including mirrors and pump lasers. Results indicate that the cw Raman laser can produce useful low-power laser radiation across the spectral range from 1 micrometers to 5 micrometers using commercially available diode lasers as pumps. Available pump lasers limit the ranges of wavelengths that can be produced at high-powers. Using real-world parameters, theory indicates photon conversion efficiencies of approximately 90% are possible. Independent experimental measurements have recorded efficiencies of over 60% without achieving optimal operating conditions. Additionally, the laser can be built to be compact, with longest dimensions on the order of 10 cm. Potential applications of the cw Raman laser include generation of high-power eye-safe radiation, generation of high-power mid-IR laser radiation for IR countermeasures, and generation of a broad range of mid-IR wavelengths for spectroscopy applications.