Ultra-compact post-compressor on-shot wavefront measurement for beam correction at PHELIX

Abstract

In order to reach the highest intensities, modern laser systems use adaptive optics to control their beam quality. Ideally, the focal spot is optimized after the compression stage of the system in order to avoid spatio-temporal couplings. This also requires a wavefront sensor after the compressor, which should be able to measure the wavefront on-shot. At PHELIX, we have developed an ultra-compact post-compressor beam diagnostic due to strict space constraints, measuring the wavefront over the full aperture of 28 cm. This system features all-reflective imaging beam transport and a high dynamic range in order to measure the wavefront in alignment mode as well as on shot.

High-energy laser facility PHELIX at GSI: latest advances and extended capabilities

“…This figure is based on the original version by J. B. Ohland [20] and its modification by M. Malki [21] . approx.…”

“…Typically, the first 30 DM modes are used during correction. The loop is closed by a SHS in a beam diagnostic that uses the equivalent-target-plane concept [40] . In a proof-ofconcept study, the capability of on-shot measurement was demonstrated and an improvement of the focused intensity on target by a factor of 3 to 5 was shown, also taking care of aberrations introduced during the daily operation by incomplete thermal relaxation of the MA of PHELIX between shots.…”

“…Note that we quantify the spot quality in absolute terms of intensity instead of a relative Strehl ratio due to high-order spatial frequencies on the surface of the focusing optic, which is still to be characterized. This figure is reproduced from Ohland et al [40] with the permission of the authors.…”

Free light-shape focusing in extreme-ultraviolet radiation with self-evolutionary photon sieves

“…( 1), which corresponds to the convergence condition. Once the image distribution is obtained, the test object can be directly obtained from the conjugation relationship between the object and image space [34][35][36][37] .…”