Twisted-Nematic Liquid-Crystal-On-Silicon Adaptive Optics Aberrometer and Wavefront Corrector

Document Type

Journal Article


Society of Photo-Optical Instrumentation Engineers


Computing, Health and Science


Engineering, Centre for Communications Engineering Research




This article was originally published as: Eng, S. H., Reinholz, F. , & Chai, D. K. (2009). Twisted-nematic liquid-crystal-on-silicon adaptive optics aberrometer and wavefront corrector. Journal of Biomedical Optics, 14(4), 044014-1 - 044014-7. Original article available here


A Hartmann-Shack wavefront sensor HSWS has been proven to be a reliable tool for the quantitative analysis of human ocular aberrations. In an active adaptive optics AO system, it has the role to monitor wave aberrations. To ensure the exclusive retrieval of Zernike coefficients for the measured ocular wavefronts, we first nullify the AO system’s aberrations. This is of particular importance in our setup with a twisted-nematic TN liquid-crystal-on-silicon LCoS chip as the wavefront manipulator due to its strong unwanted zeroorder diffractive beam. We characterize the AO system’s performance—before and after ocular corrections—by means of different parameters, including experimental and simulated point spread functions PSFs . An iterative closed-loop algorithm reduces the residual wavefront error to typical values of 0.1 m. This system constitutes a wavefront corrector that can possibly be used for high resolution retinal imaging purposes or for visual psychophysical experiments.


Link to publisher version (DOI)