2 μm passively Q-switched laser based on black phosphorus

Abstract

Few-layer black phosphorus (BP) was successfully fabricated by liquid phase exfoliation (LPE) method. By using the BP saturable absorber (SA), a passively Q-switched solid-state laser at the central wavelength of 1988 nm was demonstrated. Under an absorbed diode-pumped power of 3.38 W, an average power of 151 mW was generated with a minimum pulse width of 1.78 µs and repetition rate of 19.25 kHz, corresponding to pulse energy of 7.84 μJ. Our experimental results showed that BP could be used as an excellent SA for achieving mid-infrared solid-state pulsed lasers. To the best of our knowledge, it was the first time to obtain a Q-switched solid-state laser of 2 μm based on BP-SA.