Self-Q-switched Tm:YAP vortex laser by thermal-lensing effect

We demonstrated a self-Q-switched Gaussian laser mode and a Laguerre-Gaussian (LG0,1) laser mode at 1937.9 nm, which was directly generated by thermal lensing effect in a Tm:YAP laser. By building a Mach-Zehnder interferometer, the helical nature of the wavefront is checked. The experimental maximum output power of LG01 pulsed vortex laser was 83 mW with the repetition rate of 75.46 kHz and pulse width of 1.711 μs, corresponding to the peak power of 0.64 W and single pulse energy of 1.10 μJ. The self-Q-switched Tm:YAP vortex laser is compact and provides a convenient way to construct 2 μm pulsed vortex laser source.