Simultaneous Triple-Wavelength Operation of a Diode-Pumped Nd: GSAG Laser at 1.4 <i>μ</i> m

We present a Nd:Gd3Sc2Al3O12(Nd:GSAG) laser operating at three wavelengths via the4F3/2→4I13/2transition. The gain-to-loss balance condition for simultaneous triple-wavelength operation was analyzed numerically using a birefringent filter (BRF). Experimentally, a continuous-wave (CW) emission at 1402 nm, 1426 nm and 1440 nm was demonstrated. Under an incident pump power of 20 W at 808 nm, the laser obtained a maximum total output power of 2.23 W, corresponding to an optical-to-optical conversion efficiency of 11.2%. To the best of our knowledge, this study theoretically establishes, for the first time, the equal-threshold condition for simultaneous operation of a triple-wavelength laser using a single loss element.