A 593nm single-frequency orange–yellow pulsed laser based on Ti ₃ C ₂ Tx film passive Q-switching

A passively Q-switched single-frequency orange–yellow pulsed laser at 593[Formula: see text]nm is demonstrated using an LD-pumped Nd:YVO 4 crystal to generate simultaneous dual-fundamental waves at 1064[Formula: see text]nm and 1342[Formula: see text]nm. A Ti 3 C 2 T[Formula: see text] film (modulation depth 7.24%) serves as the saturable absorber. Intracavity photon densities are balanced at a 1:1 ratio via a Brewster window, while a Fabry–Pérot etalon enforces single longitudinal mode operation. Sum-frequency generation in an LBO crystal produces 593[Formula: see text]nm pulses. At a pump power of 5.8[Formula: see text]W, the laser delivers an average power of 50.8[Formula: see text]mW at 525.6[Formula: see text]kHz, with 36[Formula: see text]ns pulse width and 6.55[Formula: see text]MHz Lorentzian optical linewidth. Over 4[Formula: see text]h, power instability and RMS noise remain below [Formula: see text]% and 0.32%, respectively. The combination of Brewster window polarization control, F–P etalon mode selection, and Ti 3 C 2 T[Formula: see text] film Q-switching provides a feasible route to stable, low-noise single-frequency orange–yellow pulsed emission.