Adaptive-optics system with liquid-crystal phase-shift interferometer

Cheng Ying Chung*, Keng Chi Cho, Chih Chiang Chang, Cheng Hsiang Lin, Wei Chung Yen, Shean-Jen Chen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


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 0.02-π root mean square when the control loop is operated at a frequency of 30 Hz.

Original languageEnglish
Pages (from-to)3409-3414
Number of pages6
JournalApplied Optics
Issue number15
StatePublished - 20 May 2006

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