A Twyman-Green interferometer is used to measure the phase induced by a liquid-crystal spatial light modulator
(LC-SLM) via spatial-carrier phase measurement methods in order to characterize the phase response as a function of
applied voltage. With the phase response characterized, the LC-SLM can be operated in a closed-loop adaptive optics system.
Four separate phase unwrapping algorithms are evaluated for their ability to unwrap the resulting modulo 2 signal.
The evaluation process consisted of measuring the response of the liquid-crystal spatial light modulator to applied voltages,
creating a response matrix for the liquid-crystal spatial light modulator and then running the device in a closed-loop
adaptive optics system using the response matrix. The results indicated that the two least-squares phase unwrapping algorithms,
based on multigrid techniques and Fourier transform techniques, provided superior performance over a path following
algorithm and a two-dimensional extension of Itoh’s method when using these algorithms in a closed-loop adaptive