High-power, picosecond, fiber-laser green source based on BiB3O6 for synchronous pumping of MgO:SPPLT optical parametric oscillator

High-power ultrashort laser pulses in the green are of great interest for a variety of technological and scientific applications [1], including pumping ultrafast optical parametric oscillators [2]. In the absence of suitable laser gain media, the development of high-power green sources over the past 50 years has relied almost exclusively on second harmonic generation (SHG) using various nonlinear materials. The birefringent nonlinear material, bismuth triborate, BiB₃O₆ (BIBO), possesses unique nonlinear optical properties for frequency conversion from the UV to IR [3]. In particular, for SHG of fundamental radiation near 1 μm, BIBO offers wide spectral and angular acceptance bandwidths with low spatial walk-off (see Fig. 1). Moreover, BIBO also has a relatively high nonlinearity (d_eff~3.2 pm/V) as compared to the other widely used borate crystals such as LBO and BBO, making it an excellent nonlinear material for ultrafast picosecond and femtosecond SHG into the green.