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David Sánchez-de-la-Llave

Bio: David Sánchez-de-la-Llave is an academic researcher from National Institute of Astrophysics, Optics and Electronics. The author has contributed to research in topics: Phase modulation & Phase (waves). The author has an hindex of 10, co-authored 26 publications receiving 344 citations. Previous affiliations of David Sánchez-de-la-Llave include University of Massachusetts Lowell.

Papers
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Journal ArticleDOI
TL;DR: It is shown that computer generated holograms, implemented with amplitude-only liquid crystal spatial light modulators, allow the synthesis of fully complex fields with high accuracy and are appropriate for modulators whose amplitude transmittance is coupled with a linear phase modulation.
Abstract: 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.

102 citations

Journal ArticleDOI
TL;DR: A spatial filtering interferometry setup that employs a periodic spatial filter with either cosine transmittance or binary phase modulation to produce an interference pattern of the two input fields at the output plane of the system.
Abstract: 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.

43 citations

Journal ArticleDOI
TL;DR: Modified hologram cells (or macropixels) for the computer-generated double-phase holograms (DPHs), based on pixelated phase-only spatial light modulators (SLMs) exhibit a substantially improved signal-to-noise ratio, in comparison with the conventional ones.
Abstract: We propose modified hologram cells (or macropixels) for the computer-generated double-phase holograms (DPHs), based on pixelated phase-only spatial light modulators (SLMs). Such modified DPHs exhibit a substantially improved signal-to-noise ratio, in comparison with the conventional ones. The modified macropixels are formed by arrays of either 1 × 2 or 2 × 2 SLM pixels.

37 citations

Journal ArticleDOI
TL;DR: It is remarkable that the Bessel beam generated by this hologram, at the plane of this device, has peak amplitude higher than the amplitude of the beam employed to illuminate it.
Abstract: We report a highly efficient method for generation of any high-order nondiffracting Bessel beam employing a phase hologram whose transmittance coincides with the phase modulation of such a beam. It is remarkable that the Bessel beam generated by this hologram, at the plane of this device, has peak amplitude higher than the amplitude of the beam employed to illuminate it.

36 citations

Journal ArticleDOI
TL;DR: It is proved that the diffractive element that generates the vortex with maximum peak intensity has the phase modulation of a propagation-invariant qth order Bessel beam.
Abstract: An annular vortex of arbitrary integer topological charge q can be obtained at the Fourier domain of appropriate phase diffractive optical elements. In this context we prove that the diffractive element that generates the vortex with maximum peak intensity has the phase modulation of a propagation-invariant qth order Bessel beam. We discuss additional advantages of this phase element as annular vortex generator.

27 citations


Cited by
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Journal Article
TL;DR: In this article, a fast Fourier transform method of topography and interferometry is proposed to discriminate between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour generation techniques.
Abstract: A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

3,742 citations

Journal ArticleDOI
TL;DR: It is outlined how virtually all the previous ISO-standard beam diagnostic techniques may be readily replaced with all-digital equivalents, thus paving the way for unravelling of light in real time.
Abstract: Modal decomposition of light has been known for a long time, applied mostly to pattern recognition. With the commercialization of liquid-crystal devices, digital holography as an enabling tool has become accessible to all, and with it all-digital tools for the decomposition of light have finally come of age. We review recent advances in unravelling the properties of light, from the modal structure of laser beams to decoding the information stored in orbital angular momentum (OAM)-carrying fields. We show application of these tools to fiber lasers, solid-state lasers, and structured light created in the laboratory by holographic laser beam shaping. We show by experimental implementation how digital holograms may be used to infer the intensity, phase, wavefront, Poynting vector, polarization, and OAM density of some unknown optical field. In particular, we outline how virtually all the previous ISO-standard beam diagnostic techniques may be readily replaced with all-digital equivalents, thus paving the way for unravelling of light in real time. Such tools are highly relevant to the in situ analysis of laser systems, to mode division multiplexing as an emerging tool in optical communication, and for quantum information processing with entangled photons.

503 citations

Journal ArticleDOI
TL;DR: It is shown analytically and experimentally that such a vortex can be approximately generated in the Fourier transforming optical system with a computer-controlled liquid-crystal spatial light modulator.
Abstract: We introduce the concept of the perfect optical vortex whose dark hollow radius does not depend on the topological charge. It is shown analytically and experimentally that such a vortex can be approximately generated in the Fourier transforming optical system with a computer-controlled liquid-crystal spatial light modulator.

426 citations

Journal ArticleDOI
TL;DR: In this article, a vector vortex beam can be decomposed into a vector beam and a vortex, whereby the generation can be realized by sequentially using a q-plate and a spiral phase plate.
Abstract: We propose theoretically and verify experimentally a method of combining a q-plate and a spiral phase plate to generate arbitrary vector vortex beams on a hybrid-order Poincare sphere. We demonstrate that a vector vortex beam can be decomposed into a vector beam and a vortex, whereby the generation can be realized by sequentially using a q-plate and a spiral phase plate. The generated vector beam, vortex, and vector vortex beam are verified and show good agreement with the prediction. Another advantage that should be pointed out is that the spiral phase plate and q-plate are both fabricated on silica substrates, suggesting the potential possibility to integrate the two structures on a single plate. Based on a compact method of transmissive-type transformation, our scheme may have potential applications in future integrated optical devices.

161 citations

Journal ArticleDOI
TL;DR: It is shown that the amplitude and phase information from a two-dimensional complex field can be synthesized from a phase-only optical element with micrometric resolution from a 4-f optical system.
Abstract: We show that the amplitude and phase information from a two-dimensional complex field can be synthesized from a phase-only optical element with micrometric resolution. The principle of the method is based on the combination of two spatially sampled phase elements by using a low-pass filter at the Fourier plane of a 4-f optical system. The proposed encoding technique was theoretically demonstrated, as well as experimentally validated with the help of a phase-only spatial light modulator for phase encoding, a conventional CMOS camera to measure the amplitude of the complex field, and a Shack-Hartmann wavefront sensor to determine its phase.

151 citations