Open AccessAccurate encoding of arbitrary complex fields with amplitude-only liquid crystal spatial light modulators
Author(s) -
Víctor Arrizón,
Guadalupe Méndez,
David Sánchez-de-la-Llave
Publication year - 2005
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/opex.13.007913
Subject(s) - optics , spatial light modulator , amplitude , holography , signal (programming language) , amplitude modulation , transmittance , bessel function , phase modulation , modulation (music) , optical modulator , phase (matter) , envelope (radar) , physics , computer science , frequency modulation , acoustics , telecommunications , phase noise , bandwidth (computing) , radar , quantum mechanics , programming language
We show that computer generated holograms, implemented with amplitude-only liquid crystal spatial light modulators, allow the synthesis of fully complex fields with high accuracy. Our main discussion considers modified amplitude holograms whose transmittance is obtained by adding an appropriate bias function to the real cosine computer hologram of the encoded signal. We first propose a bias function, given by a soft envelope of the signal modulus, which is appropriate for perfect amplitude modulators. We also consider a second bias term, given by a constant function, which results appropriate for modulators whose amplitude transmittance is coupled with a linear phase modulation. The influence of the finite pixel size of the spatial light modulator is compensated by digital pre-filtering of the encoded complex signal. The performance of the discussed amplitude CGHs is illustrated by means of numerical simulations and the experimental synthesis of high order Bessel beams.