Open AccessHadamard circular masks: high focal depth with high throughput
Author(s) -
Luis M. Ledesma-Carrillo,
Cristina M. Gómez-Sarabia,
M. Torres-Cisneros,
Rafael Guzmán-Cabrera,
Cipriano Guzmán-Cano,
J. OjedaCastañeda
Publication year - 2017
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.017004
Subject(s) - strehl ratio , optics , focus (optics) , binary number , optical transfer function , hadamard transform , physics , modulation (music) , depth of focus (tectonics) , computer science , mathematics , adaptive optics , paleontology , arithmetic , subduction , quantum mechanics , biology , acoustics , tectonics
We present a class of binary masks that encode, in polar coordinates, the values of a Hadamard matrix of order N. For order N ≥ 2, the binary masks increase the Strehl ratio vs. focus error by the factor N, with the highest possible light throughput. Since a Strehl ratio with high tolerance to defocus does not guarantee a modulation transfer function (MTF) with low sensitivity to focus errors, then, we show that for N = 16 the binary mask reduces also the impact of focus error on the MTF. Equivalently, the discrete binary mask has Fisher information with low variations to defocus.