Abstract

We report a CW, frequency doubled, Nd:GdVO₄ self-Raman laser producing 2.51 W of CW yellow emission with a 12.2 % overall optical (diode-to-yellow) conversion efficiency. This high level of output power is a result of a laser design which minimises thermal loading of the laser crystal, minimises resonator loss at the fundamental and first Stokes wavelength and maximises the collection efficiency of the yellow light generated in the doubling crystal; each of these key design goals were identified in [1]. More specifically, the laser was pumped at 880 nm, as opposed to 808 nm, resulting in a reduced thermal load in the self-Raman laser crystal and enabled the use of higher pump powers. The reduced thermal lens in turn allowed for a longer (20 mm) Nd:GdVO₄ crystal to be used, resulting in higher Raman conversion. Resonator losses were kept as low as possible, by using a single “self-Raman” crystal to perform the dual functions of laser gain material and Raman shifting medium [2]. For efficient collection of the yellow emission into a single output beam, an intracavity dichroic mirror was used with the additional benefit of preventing any thermal loading of the laser crystal caused by absorption of yellow light by the laser crystal.

© 2009 IEEE