Passively Q-switched Tm/Ho composite laser

We explored Q-switching mechanism for the newly proposed Tm/Ho composite laser via developing a hybrid resonator for separating the intra-cavity Tm laser modulated by the saturable absorber(SA). With a Cr:Zn Se SA, successful passively Q-switching process with the maximum average output power of 474 m W and the shortest pulse width of 145 ns were obtained at the pulse repetition frequency of 7.14 k Hz, where dual wavelength oscillation in both 2090 nm and 2097 nm was observed. This work provides an effective way for a direct laser diode(LD) pumped Q-switched Ho laser, which is compact and accessible. Furthermore, the current SA could be replaced by the 2 D materials with broadband saturable absorption such as topological insulators or transition-metal dichalcogenides for seeking novel PQS lasers.