Open- and closed-loop aberration correction by use of a quadrature interferometric wave-front sensor.

Experimental results are presented for an adaptive optics system based on a quadrature Twyman-Green interferometric wave-front sensor. The system uses a circularly polarized reference beam to form two interferograms with a pi/2 phase shift. The experiments conducted used Kolmogorov phase screens to simulate atmospheric phase distortions. Strehl ratio improvements by a factor of 8, to an absolute value of 0.45, are demonstrated.

Breadboard testing of a phase-conjugate engine with an interferometric wave-front sensor and a microelectromechanical systems-based spatial light modulator.

Laboratory breadboard results of a high-speed adaptive-optics system are presented. The wave-front sensor for the adaptive-optics system is based on a quadrature interferometer, which directly measures the turbulence-induced phase aberrations. The spatial light modulator used in the phase-conjugate engine was a microelectromechanical systems-based piston-only correction device with 1024 actuators. Laboratory experiments were conducted with this system utilizing Kolmogorov phase screens to simulate atmospheric phase distortions. The adaptive-optics system achieved correction speeds in excess of 800 Hz and Strehl ratios greater than 0.5 with the Kolmogorov phase screens.