Nonlinear-mirror mode-locked crystal waveguide laser by intracavity fourth-harmonic loss modulation

We present a nonlinear-mirror (NLM) mode-locked crystal waveguide laser. By adding nonlinear crystals into tradi-tional NLM devices, the fourth harmonic is generated to form loss modulation, which suppresses the Q-switching instability of mode-locked lasers and achieves the optimal equivalent transmittance. The NLM mode-locked laser delivers similar to 30 W average power with a repetition rate of 32.2 MHz and a pulse width of 950 fs. It is revealed that this novel, to the best of our knowledge, design with simple, robust, and reliable structure has a great potential in the development of high-power mode-locked laser. (c) 2023 Optica Publishing Group