Research On The Actively Q-switched Kerr-lens Mode-locking Eye-safe Laser Based On The Mode Injection Locking Technology

Water has a large absorption coefficient in this spectral region at the vicinity of 1.5μm, which can prevent the energy from reaching the retina. High power laser at eye-safe wavelength region are widely used in medical treatment, remote sensing, radar system and optoelectronic countermeasure. The current researches on the all-solid-state Raman laser and Kerr-lens mode-locked laser were reviewed, including the optical parameter oscillator, first stokes and high order stokes laser method. A method to reveal eye-safe laser with picosecond pulse scale was put forward as stated below.First, the Q-switch technology integrated with the Kerr-lens has dual modulation effect on the laser pulse, which compress the laser pulse duration, increase the laser peak power and the Raman conversion efficiency.Second, the injection mode lock technology was employed in the experiment. The pulse was shaped by the mode beating situation. The fundamental laser was injected into the Raman cavity, when the fundamental modes and the first-stokes beat the oscillating frequencies of the fundamental cavity and the Raman cavity, the Raman cavity was able to damp the energy from the fundamental cavity efficiently. By changing the proportional relation between the lengths of two cavity, the damping situation can be modified, the modulation depth of the mode locking and the pulse width can be changed.Third, the First-stokes laser at 1525 nm was obtained in the experiment using Nd:YAP as laser crystal and YVO4 as Raman medium, and the maximum output power was 3.5 W, the pulse repetition rate was up to 2 GHz, and the pulse time duration was 178 ps, with different optimization design.