Twisted-Nematic Liquid-Crystal-On-Silicon Adaptive Optics Aberrometer and Wavefront Corrector
Society of Photo-Optical Instrumentation Engineers
Computing, Health and Science
Engineering, Centre for Communications Engineering Research
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.