title: Adaptive-optics system with liquid-crystal phase-shift interferometer.
abstract: We develop an adaptive-optics system based on a Mach-Zehnder radial shearing interferometer with liquid-crystal-device (LCD) phase-shift interferometry (PSI). Using accurate phase calibration and transient nematic driving of the LCD, the developed three-step PSI procedure can be achieved in a time of 5 ms. The proposed Mach-Zehnder radial shearing PSI method reconstructs the phase information using a digital signal processor (DSP). The DSP then computes appropriate control signals to drive a deformable mirror in such a way as to eliminate the wavefront distortion. The current adaptive-optics system is capable of suppressing low-frequency thermal disturbances with a signal-to-noise ratio improvement of more than 20 dB and a steady-state phase error of less than 0.02pi root mean square when the control loop is operated at a frequency of 30 Hz.
authors.affiliation: Department of Mechanical Engineering, National Central University, Chung-Li, Taiwan.
authors.forename: Cheng-Ying
authors.initials: CY
authors.lastname: Chung
authors.forename: Keng-Chi
authors.initials: KC
authors.lastname: Cho
authors.forename: Chih-Chiang
authors.initials: CC
authors.lastname: Chang
authors.forename: Cheng-Hsiang
authors.initials: CH
authors.lastname: Lin
authors.forename: Wei-Chung
authors.initials: WC
authors.lastname: Yen
authors.forename: Shean-Jen
authors.initials: SJ
authors.lastname: Chen