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DIRECTED
ENERGY
PROFESSIONAL
SOCIETY
Abstract: 24-Symp-038
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UNCLASSIFIED, PUBLIC RELEASE
Multi-Conjugate Adaptive Optics Design and Experiments
To address emerging threats to Navy ships such swarming UAVs and anti-ship cruise missiles, increasing the range and effectiveness of HEL beam propagation is a critical task. Compensation of deep turbulence using conventional adaptive optics faces many challenges due to strong scintillations and highly dynamic wavefront aberrations that needs to be measured and compensated with a single wavefront sensor and a single deformable mirror. With multiple wavefront sensors and deformable mirrors placed specific conjugate planes along the beam propagation path, multi-conjugate adaptive optics aims to lessen the scintillation effects and reduce the phase compensation requirements each wavefront sensor and deformable mirror needs to handle. Due to the complexity and constraints of the actual HEL systems however, it is difficult to place more than a couple of wavefront sensors and wavefront correctors in the optical path. At the Naval Postgraduate School, we developed a laboratory multi-conjugate adaptive optics testbed that uses two Shack-Hartmann wavefront sensors and two deformable mirrors. In the testbed, atmospheric turbulence is simulated with three reconfigurable rotating phase plates with D/r0 = 10, D/r0 = 15, and D/r0 = 25 phase profiles, respectively. A 96-channel Micro-Membrane Deformable Mirror (MMDM) is placed on the pupil plane of the optical system and a 349-channel lead magnesium niobate (PMN) deformable mirror is placed on a conjugate plane within the beam path. Both multi-conjugate adaptive optics and single-conjugate adaptive optics experiments were performed under various simulated turbulence conditions using the testbed. Performance of the multi-conjugate adaptive optics compared to the single conjugate adaptive optics is evaluated using several beam propagation metrics such as peak intensity, wavefront error, and intensity log-amplitude variance of the laser beam. In this presentation, results of these adaptive optics experiments will be presented.
UNCLASSIFIED, PUBLIC RELEASE
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