Multiple and selectable wavelength green laser generation based on coaxial diode-end-pumping

Abstract

A multi-wavelength green laser is presented based on a coaxial diode-end-pumping configuration by intracavity frequency doubling with a nonlinear crystal. The composite gain media (Nd:YVO4 and Nd:GdVO4) are placed coaxially and share one pump diode around 808 nm to generate two competition-free fundamental laser at 1064.4 nm and 1063.2 nm. The nonlinear crystal (KTP or LBO) are satisfactory for second-harmonic generation (SHG) and sum-frequency generation (SFG) with different fundamental wavelengths. Stable multi-watt green lasers at 532.2 nm, 531.6 nm and 531.9 nm are simultaneously obtained. Through gain controlling by tuning the pump focusing depth and pump absorption, the power ratio for those wavelengths and pulse interval can be manipulated actively. A rate-equation model is proposed and the experimental results coincide with the simulations. By replacing the gain media (Nd:YAG, Nd:GSGG, Nd:YAP, etc), various green lasers with multiple and selectable wavelengths are possible, which have great potential in practical applications.