Bismuth quantum dots as an optical saturable absorber for a 1.3 μm Q-switched solid-state laser.

Abstract

Two-dimensional bismuth has attracted extensive attention for its unique properties, such as a moderate bandgap, high carrier mobility, and high stability. In this work, a uniform bismuth quantum dots saturable absorber (BiQDs-SA) was successfully fabricated by the liquid-phase exfoliation method. It was successfully employed in a passively Q-switched bulk laser operating at the telecommunication wavelength of 1.3μm. The as-fabricated BiQDs-SA-based 1.3μm Q-switched laser not only exhibits low timing jitter but also shows long-term stability for several days. The maximum average output power of 125mW was obtained with the shortest pulse width of 510ns and repetition rate of 135kHz, corresponding to single-pulse energy and pulse peak power of 0.9μJ and 1.8W, respectively. The results indicate that BiQDs-SA is a potential optical modulator for passively Q-switched solid-state lasers.