New deformable mirror technology and associated control strategies for ultrahigh intensity laser beam corrections and optimizations

摘要

When ultra high intensity lasers facilities were in their early development, the only concern was getting laser pulses with the right energy and pulse duration. As facilities are orienting toward the end users, they are now required to deliver a laser beam with additional qualities like a focal spot with constant quality. That is why Adaptive Optics is now a standard feature for the current ultra high intensity lasers facilities to correct for the aberrations of the beam exiting the laser chain. However, the very last optical components, like the off axis parabola to focus the beam induce aberrations that cannot be directly corrected as they are located after the wavefront sensing. We present a new technology of deformable mirror and a new correction strategy to get optimal focal spot in the experiment chamber as well as measurement of the actual beam quality in the chamber while the beam is used for experiments. These deformable mirrors were designed taking into account needs of ultra intense laser applications. They provide exceptional stability, optical quality and innovative features like scalability and maintenance of the reflective surface. The method of correction proposed uses usual adaptive optics loop to correct for all the aberration from the laser chain, as well as additional steps to get an optimal focal spot in the experiment chamber on a non amplified beam, and to correct and measure the actual beam quality on the amplified beam while it is used for experiments.