Characteristics of a stable, injection Q-switched Nd:phosphate glass regenerative amplifier for a chirped pulse amplification based Table Top Terawatt laser system

摘要

A flash lamp pumped, injection Q-switched, cavity dumped Nd:phosphate glass regenerative amplifier has been designed, set up and characterized for an Nd:glass Table Top Terawatt laser system. The amplifier gain, output energy stability, amplified spontaneous emission (ASE) level, amplification time, and output pulse spectrum have been measured for different seed pulse energies and pump levels. The amplifier provides an overall gain of 3 X 10~(7) in 61 round trips at an electrical pump energy of 300 J. Stable amplification has been simulated and demonstrated. The output energy fluctuations are found to reduce by a factor of 10 by ejecting the amplified pulse with a delay of five round trips after the fluence has built up to its peak level. The experimental results are found to be consistent with a theoretical model of the regenerative amplifier. The ASE intensity has been estimated using measured dependence of amplification time with respect to different seed pulse energies.