Compensation of thermal lensing in solid-state laser gain media using phantom pulses

Phantom pulses are low energy, high repetition rate pulses used to induce controlled thermal lensing in the laser rod for purposes of achieving full output energy at single shot operation and/or at a broad range of repetition rates. The energy of the phantom pulses is below the lasing threshold and the repetition rate is low enough so that there is minimal stored energy left in the gain media when the lasing pulse occurs. The method of using phantom pulses to increase performance benefits resonators that perform better at a higher average power. Additionally phantom pulses can be used to control divergence over a resonator’s operational range.