External-cavity tunable yellow-red laser based on Ng-cut KGW Raman conversion and frequency mixing

We demonstrated a wavelength discretely tunable laser with outputs at 572.6 nm, 589.1 nm, 603.8 nm, and 611.8 nm using external cavity Ng-cut KGW Raman conversion and intracavity frequency mixing. The multiple visible wavelengths were generated by utilizing this specially cut KGW crystal and the g[mm]g Raman configuration, as well as the temperature-dependent phase-matching characteristic of the LBO crystal. The maximum output powers at 572.6 nm, 589.1 nm, 603.8 nm, and 611.8 nm were measured to be 227 mW, 175 mW, 258 mW, and 103 mW respectively, with nearly fundamental Gaussian beam profiles. This work provides a monolithic setup capable of producing tunable yellow-red laser outputs through Raman and \(\chi ^2\) frequency conversions for various applications such as air detection, optogenetics, biomedicine, and chemical analysis.