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

Layered rhenium diselenide (ReSe₂) has triggered strong interest because of its outstanding optical and electrical properties. In this paper, we prepared a high-quality multilayer ReSe₂ 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 ReSe₂ is a promising alternative as a nonlinear optical modulator near the 2 μm region.