Interferometric adaptive optics for high-power laser pointing, wavefront control, and phasing

Abstract

Implementing the capability to perform fast ignition experiments, as well as, radiography experiments on the National Ignition Facility (NIF) places stringent requirements on the control of each of the beam's pointing and overall wavefront quality. One quad of the NIF beams, 4 beam pairs, will be utilized for these experiments and hydrodynamic and particle-in-cell simulations indicate that for the fast ignition experiments, these beams will be required to deliver 50%(4.0 kJ) of their total energy(7.96 kJ) within a 40 μm diameter spot at the end of a fast ignition cone target. This requirement implies a stringent pointing and overall phase conjugation error budget on the adaptive optics system used to correct these beam lines. The overall encircled energy requirement is more readily met by phasing of the beams in pairs but still requires high Strehl ratios, S r , and RMS tip/tilt errors of approximately one μrad. To accomplish this task we have designed an interferometric adaptive optics system capable of beam pointing, high Strehl ratio and beam phasing with a single pixilated MEMS deformable mirror and interferometric wave-front sensor. We present the design of a testbed used to evaluate the performance of this wave-front sensor below along with simulations of its expected performance level.

Focusing through dynamic scattering media

“…The Kilo-SLM has been used previously in a variety of applications requiring control of dynamic aberrations containing high spatial and/or temporal frequencies [11][12][13][14][15][16][17][18][19]. It is comprised of 1020 mirror segments in a 32 × 32 array where the 4 corner segments are fixed.…”

Focusing through dynamic disordered media using a MEMS spatial light modulator

“…The work presented here describes experimental results on optical transmission through nearly opaque media and focusing using a microelectromechanical system (MEMS) reflective spatial light modulator SLM (Boston Micromachines Corporation kiloSLM®) [10], which can speed optimization rates, enabling robust focusing at intensities up to several hundred times the background level. This SLM has been used previously in a variety of applications requiring control of dynamic aberrations containing high spatial and/or temporal frequencies [11][12][13][14][15][16][17][18][19]. It is comprised of 1020 controllable mirror segments in a 32 × 32 array (with immobile mirror segments at the four corners of the array).…”

Stability improvement of a wavefront correction system for robust image acquisition

“…2. The outer actuators placed on line A were not used because of instability [26]. The reflective surface of the mirror ended at the last actuator row, and the outer actuators had no constraint on their outer edge.…”