A single frequency Nd:YAG Q-switched laser with timely controllable firing time by a gated Pockels cell

Abstract

A single frequency Q-switched Nd:YAG laser with precisely controllable firing time was realized by using a single gated Pockels cell. We have devised a setup of injecting seeding in that a CW seeded laser radiation entrapped inside the ring cavity function as a pulse seeding for the slave laser. A pulse seeding instead of CW seeding can avoid the cavity length scanning to realize stable seeding. This seeding process is completed before Pockels cell opening edge in which the entrapped seed in the slave cavity initialize the starting of slave lasing once the ring cavity is closed. In this design, we use only one adjustable gated Pockels cell to realize these two functions, (1) at the opening edge, close the slave cavity and start the laser oscillation, and (2) at the falling edge, dump the cavity when the lasing pulse energy optimizes. Because the Q-switch firing time is precisely controlled by the Pockels cell's timing, thus it can be precisely controlled. The advantage of the realized regime is in stable laser operation with no need in adjustment of the mode of the cavity to the seeded wavelength. In experiments, we found that the frequency of the Q-switched laser radiation matches well to the injected seeded laser mode. With slave oscillator, the output pulse energy can be above 80 mJ to close 100 mJ depending on the operating condition and pulse width is about 10 ns.