Study on CW fundamental and self-frequency doubling laser of Nd 3+:GdAl 3(BO 3) 4 crystal

Using a CW Ti:sapphire tunable laser as a pumping source, 1.34 and 1.06 μm fundamental lasers as well as the green laser emission by self-frequency doubling of the 1.06 μm laser have been performed in Nd ³⁺:GdAl ₃(BO ₃) ₄ crystal with different transmittance output couplers. The optical conversion efficiencies were measured to be 32% for T=5.2% at 1.06 μm and 15.5% for T=1.78% at 1.34 μm respectively. 6.4 mW of green laser power was obtained with an absorbed pump power of 1.261 W at 807 nm. The laser output at 1.06 μm as a function of pumping wavelength was also measured, and the results show that 750 nm is also an available pumping wavelength. The internal loss and net-gain cross section were estimated to be 0.009 cm^-1, 2.08×10 ^-19 cm² and 0.013 cm^-1, 5.04×10 ^-20 cm² for 1.06 and 1.34 μm respectively. The IR laser and its self-frequency doubling laser emission can be further improved by optimizing the device design.