Few-layer GaSe nanosheet-based broadband saturable absorber for passively Q-switched solid-state bulk lasers.

In this paper, few-layer two-dimensional (2D) GaSe nanosheets were fabricated and utilized as broadband saturable absorbers (SAs) for passively -switched (PQS) solid-state bulk lasers operating at 1.06 and 1.99 µm. For 1.06 µm laser operation, the maximum average output power, the shortest pulse width, and the largest single pulse energy were determined to be 438 mW, 285 ns, and 2.31 µJ, respectively, while for 1.99 µm PQS laser operation, they were 937 mW, 383 ns, and 9.56 µJ. Our results identified the great potential applications of few-layer 2D GaSe nanosheets for practical optical modulators such as SAs for pulsed laser generation.