The energy band structure analysis and 2 μm Q-switched laser application of layered rhenium diselenide.

Layered rhenium diselenide (ReSe) has triggered strong interest because of its outstanding optical and electrical properties. In this paper, we prepared a high-quality multilayer ReSe saturable absorber with a liquid-phase exfoliation method and characterized its saturable absorption properties around 2 μm. During the Q-switching regime, a maximum average output power of 1.7 W was obtained. A shortest pulse width of 925.8 ns was measured and the corresponding single pulse energy and peak power were 17.6 μJ and 19.0 W, respectively. The results indicate that layered ReSe is a promising alternative as a nonlinear optical modulator near the 2 μm region.