Emission wavelength selection and tuning in the 4F3/2-4I11/2 manifolds of a Nd:KGd(WO4)2 solid-state laser

Abstract

We present a Nd:KGW laser with a wavelength selectable intracavity loss scheme comprising a notch filter and external-cavity feedback, which enables distinct continuous-wave laser oscillation regimes. Based on the spectroscopy of the - transition in Nd:KGW, we have achieved tunable laser oscillation at either 1067 nm, 1076 nm or 1085 nm corresponding to different spectral peaks of the emission cross-section. An adequate balance of the intracavity loss also allows for dual-wavelength operation at both 1067–1076 nm and 1076–1085 nm peaks, and the inclusion of an additional external reflector permits dual-wavelength oscillation in the vicinity of the main emission peak at 1067 nm. From the external-cavity laser theory perspective, in our approach, the tuning mechanism is treated as an effective intracavity loss instead of an effective reflectivity treatment. The key parameters for further improving the emission wavelength range and tunability are identified and iscussed.