Mo2TiAlC2 as a Saturable Absorber for a Passively Q-Switched Tm:YAlO3 Laser

Abstract

Owing to their remarkable characteristics, two-dimensional (2D) layered, MAX phase materials have garnered significant attention in the field of optoelectronics in recent years. Herein, a novel MAX phase ceramic material (Mo2TiAlC2) was prepared into a saturable absorber (SA) by the spin-coating method for passively Q-switching (PQS), and its nonlinear optical absorption properties were characterized with a Tm:YAlO3 (Tm:YAP) nanosecond laser. The structure characteristics and composition analysis revealed that the Mo2TiAlC2 material exhibits a well-defined and stable structure, with a uniform thin film successfully obtained through spin coating. In this study of a PQS laser by employing a Mo2TiAlC2-based SA, an average output power of 292 mW was achieved when the absorbed pump power was approximately 4.59 W, corresponding to a central output wavelength of 1931.2 nm. Meanwhile, a stable pulse with a duration down to 242.9 ns was observed at a repetition frequency of 47.07 kHz, which is the narrowest pulse width recorded among PQS solid-state lasers using MAX phase materials as SAs. Our findings indicate that the Mo2TiAlC2 MAX phase ceramic material is an excellent modulator and has promising potential for ultrafast nonlinear photonic applications.