Laser oscillation of Nd:KGd(WO4)2 in the 1.538 μm eye-safe range

The radiation at around 1.5 mum has been extensively investigated over the last few years for eye-safe applications. This paper describes the development and performance of a pulsed solid-state laser based on nonlinear frequency conversion of the Nd:KGd(WO4)(2) fundamental radiation into the near-infrared region of the spectrum. Neodymium-doped potassium gadolinium tungstate Nd:KGd(WO4)(2) (Nd:KGW) possesses a combination of spectral and lasing characteristics uniquely favorable for laser operation. The explanation for the high efficiency which can be achieved with this material follows from high effective stimulated-emission cross section of laser transition. Also, in contrast to Nd:YAG, Nd:KGW is an efficient Raman medium. In the present paper most attention has been concentrated on the self-conversion of the laser wavelength at 1.351 mum to the first Stokes line at 1.538 mum, In conclusion, we have demonstrated a compact low-threshold source for the near-IR in a configuration of an intra-cavity solid-state Raman laser based on a flashlamp-pumped Nd:KGW laser crystal. The small size and high efficiency of this laser makes it an attractive source for a large number of applications such as communications and optical atmospheric studies.