Biomedical subjects

David Sánchez-de-la-Llave

Publications and source records attributed to David Sánchez-de-la-Llave.

3 recordsLinked to original sources

PubMed2004

Common-path interferometry with one-dimensional periodic filters.

We discuss a spatial filtering interferometry setup that employs a periodic spatial filter with either cosine transmittance or binary phase modulation. The setup's input plane is formed by two separate windows, one of which supports a phase object and the other, a reference beam. Using the appropriate frequency and orientation of the filter produces an interference pattern of the two input fields at the output plane of the system. The main attributes and advantages of the setup are discussed and experimentally illustrated with the example of a binary phase periodic filter implemented with a spatial light modulator.

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PubMed2003

Nonlinear common-path interferometer: an image processor.

A single-lens optical setup with a nonlinear medium placed in its geometrical focal plane is used to contrast a phase disturbance. This setup blends the robustness of phase-contrast methods with an optical nonlinear intensity-dependent medium and the usefulness of traditional interferometric techniques. We show that the ratio of the total illumination area to the phase-object area determines an adequate phase-disturbance contrast.

Journal Article↗

PubMed2002

Influence of illuminating beyond the object support on Zernike-type phase contrast filtering.

A general analysis of the image fill-factor influence on Zemike-type phase contrast filtering is presented. We define image fill factor as the ratio of the object support area over the illuminating area. We first consider binary-phase objects and then generalize to arbitrarily quantized and continuous-phase objects. Numerical simulations are presented for binary- and quadratic-phase objects, where the contrast of the output image is evaluated as a function of the image fill factor, image phase variations, and filter phase. The results obtained show that the image fill factor can significantly modify the contrast and irradiance of the contrasted image.

Journal Article↗