High Power Diamond Raman Lasers

Abstract

Laser gain materials possessing high thermal conductivity and robust mechanical properties are key prerequisites for high power lasers. We show that diamond, when configured as a Raman laser, enables access to these and other extreme properties, providing an important new route to high power and high brightness beam generation. Recent achievements in pulsed and continuous wave oscillators, beam combining amplifiers and single longitudinal mode oscillators are summarized, along with wavelength extension of these concepts through adaption to other pumps, use of Raman cascading, and intracavity harmonic generation. To date, diamond laser powers have attained 750 W with efficiency and beam quality so far unperturbed by nonlinear or thermally-induced side-effects. We describe paths to higher power through aperture scaling of oscillators and amplifiers. Large factor brightness enhancement of low coherence inputs is demonstrated using multiple pump beams (via Raman beam combination) or highly multimode pumps. Future directions for direct diode pumping, and for realizing extraordinary power and power density through reduced temperature operation and isotopically-enriched diamond, are also discussed. Our results indicate that diamond is emerging as a generic high-power laser technology with advantages of brightness (high average power and high beam quality) and wavelength range.