Biomedical subjects
Publications and source records attributed to M Testorf.
In a recent paper [J. Opt. Soc. Am. A 16, 113 (1999)] a thin-element approximation of diffractive optical elements was used to describe diffraction of oblique incident wave fronts. This expression motivated by a ray optical analysis is shown to be incorrect. I discuss how the thin-element approximation can be generalized to arbitrary diffraction geometries. This includes an intuitive interpretation of the results.
We describe the design of Fourier-type phase-only array generators. The numerical optimization employs the Fienup algorithm, where the parageometric design of the phase retardation profile, with the form of a lenslet array, is used as the initial guess of the optimization process. This approach provides designs with high performance that can be obtained with comparatively low computing effort. This is particularly true for elements generating large spot arrays. For symmetric reconstruction fields, the optimized phase profile typically has the same symmetry as that for the reconstruction field and can be easily unwrapped.
The Wigner distribution function is used to analyze moiré patterns that originate from a superposition of nonperiodic masks. For patterns with well-defined local frequencies, the concept of the Wigner distribution function allows one to extend the description of the moiré effect in terms of vector sums. How this picture can be applied to design moiré patterns and to analyze their information content is also discussed.