Graphene-based passive Q-switching of a Dy³⁺,Tb³⁺:LuLiF₄ yellow laser

We report solid-state continuous-wave (cw) and Q-switched lasers directly emitting in the yellow spectral region, which include a Dy3+,Tb3+:LuLiF4 crystal as the laser material and a single-emitter blue laser diode (LD) as the pump source. Without resorting to any nonlinear conversion process, a maximum output power of 351 mW is obtained for the cw yellow laser with a slope efficiency of 15% at the wavelength of 573.9 nm. For generating the Q-switched yellow laser, a monolayer graphene is used as the saturable absorber. The maximum average output power of the Q-switched yellow laser is determined to be 85 mW. The shortest pulse width is obtained as approximately 596 ns, which corresponds to a repetition rate of 78 kHz. The calculated pulse energy and peak power are nearly 1.1 mu J and 1.8 W, respectively. Overall, the proposed approach exhibits immense potential for fabricating compact and economical solid-state cw and Q-switched yellow lasers.