Passively mode-locked 1.34 μm bulk laser based on few-layer black phosphorus saturable absorber.

By using few-layer black phosphorus (BP) as saturable absorber, an efficient mode-locked Nd:GdVO ₄ bulk laser operating at 1.34 μm was realized. An average output power of 350 mW was achieved with a slope efficiency of 15%. The corresponding mode-locking pulse repetition rate, pulse duration and pulse energy were 58.14 MHz, 9.24 ps and 3.0 nJ, respectively. To the best of our knowledge, the pulse width is the shortest among the mode-locked 1.34 μm neodymium lasers ever obtained with other two-dimensional materials saturable absorber. The results clearly indicate the few-layered BP is a kind of promising saturable absorber for ultrafast 1.34 μm lasers.