Long Pulse Narrowband XeCl Laser Studies

摘要

Long pulse narrowband e-beam pumped excimer lasers are of interest forapplications that require large amounts of energy to be delivered to a target. The e-beam pumping allows scaling to large energies. Increasing the laser pulse length while keeping the energy constant results in a lower laser flux, which eases design constraints on the laser optics for large systems. Atmospheric transmission can be improved by remaining under the simulated Raman scattering threshold, and laser target coupling improved by virtue of a lower plasma temperature. Narrow bandwidths are required to increase the efficiency of nonlinear processes, such as stimulated Raman and Brillouin scattering, which are used for beam combining, frequency shifting, and beam quality cleanup. With these advantages in mind, a program to develop, optimize, and study a long pulse narrowband XeCl laser was undertaken. The MLI Maximizer Laser, which had been previously modified to provide a long pulse e-beam, was used for the experiments. The narrowbanding was accomplished using intracavity etalons, and provided a 5 msec, 300 MHz XeCl laser pulse. This is the longest pulse width obtained with an e-beam pumped excimer laser. (rrh)