Phase retrieval of recorded kinoform transmittance and estimation of the phase-recording curve characteristic

Methods are presented for recovering, by the use of the basic Gerchberg-Saxton algorithm, the complex-valued transmittance of a recorded kinoform and for estimating the phase-recording curve characteristic of a kinoform-fabrication system by comparison of the phase to be recorded with that actually recorded. Related issues considered here are the shift of the central sampling point from the optical axis in the Fourier-image domain, a kinoform phase sequence suitable for estimating the curve characteristic, the initial estimate of the iterative algorithm, and the influence of errors in the measurement of the kinoform or of the Fourier-image amplitude. Results of an optical experiment with a fabrication system including a photographic process are discussed and shown to confirm the effectiveness of the proposed methods.