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Publications (56)
This paper presents a holographic sensor based on reflection holograms recorded in the commercial photopolymer Bayfol® HX 200. The recording geometry and index modulation of the hologram were optimised to improve accuracy for this specific application. The sensor was subjected to tests using various analytes, and it exhibited sensitivity to acetic...
Modal decomposition of light is essential to study propagation properties of waveguides and photonic devices. Modal analysis can be carried out by implementing a computer generated hologram acting as a match filter in a spatial light modulator. In this work, a series of aspects to be taken into account in order to get the most out of this method ar...
We present a modal analysis of coupled two-core integrated waveguides fabricated by femtosecond laser writing as a function of the core-to-core distance, illuminating position and input light wavelength. In order to do that we use the correlation filter method, implementing the computer generated holograms in a phase-only spatial light modulator. D...
Modal decomposition of light is essential to study its propagation properties in waveguides and photonic devices. Modal analysis can be carried out by implementing a computer-generated hologram acting as a match filter in a spatial light modulator. In this work, a series of aspects to be taken into account in order to get the most out of this metho...
A wavelength multiplexing procedure for color transmission volume holograms of diffusing objects recorded in Bayfol® HX200 photopolymer is proposed. For the recording, three lasers of 442 nm, 532 nm and 633 nm, and a Spectralon® diffusing object were used for monochromatic and polychromatic calibration. Monochromatic calibration shows that the maxi...
An optimized wavelength multiplexing procedure for color reflection holograms of diffusing objects recorded in Bayfol® HX photopolymer is proposed. It is based on simultaneous initial illumination of all the wavelengths and sequential shuttering down of the laser beams involved. Three lasers of 442 nm, 532 nm and 633 nm were selected, as a tradeoff...
A novel stacking procedure is presented for volume phase holographic gratings (VPHGs) recorded in photopolymer material using Corning Willow Glass as a flexible substrate in order to achieve broader angular and spectral selectivity in a diffractive device with high efficiency for solar and LED applications. For the first time to our knowledge, we h...
A holographic solar concentrating system with a Silicon photovoltaic (PV)cell is designed, constructed and characterized. The design is based on a previous system and is further optimized. The cylindrical holographic lenses forming the concentrating system are modeled with a ray-tracing algorithm based on Coupled Wave Theory and are recorded on Bay...
Concentrating photovoltaics for building integration can be successfully carried out with Holographic Optical Elements (HOEs) because of their behavior analogous to refractive optical elements and their tuning ability to the spectral range that the photovoltaic (PV) cell is sensitive to. That way, concentration of spectral ranges that would cause o...
A solar concentration system formed by two holographic cylindrical lenses is proposed. It redirects part of the incident solar spectrum towards a PV cell, concentrating only the cell’s most efficient wavelength range, while the rest is transmitted, not causing overheating. Simulations with one- and two-axes tracking are carried out.
Las estructuras multinúcleo integradas son buenas candidatas para mejorar las prestaciones de los dispositivos ópticos activos [1]. Estamos trabajando en la caracterización de estas estructuras fabricadas mediante escritura por láser de femtosegundo [2]. Se presentan las dos técnicas de caracterización modal implementadas por nuestro grupo.
The use of volume and phase holographic elements in the design of photovoltaic solar concentrators has become very popular as an alternative solution to refractive systems, due to their high efficiency, low cost and possibilities of building integration. Angular and chromatic selectivity of volume holograms can affect their behavior as solar concen...
The requirements for the generation of optical vortices with ultra-short and ultra-intense laser pulses are considered. Several optical vortice generation procedures are analysed, specifically those based on diffractive elements, such as computer generated holograms (CGH). Optical vortices achromatization techniques are studied. Volume phase hologr...
Among the different types of Holographic Optical Elements (HOEs), volume holograms have been studied as solar concentrators attending to some interesting properties as the high optical efficiency achieved (they can reach 100% efficiency for a selected wavelength). They may be utilized in different configurations: plane gratings, which are not conce...
True colour Denisyuk-type hologram recording of diffusing objects in Bayfol® HX 102 self-developing photopolymer has been studied. In a first stage, monochromatic Denisyuk holograms of a standard white diffuser (Spectralon) have been recorded using lasers with wavelengths 442, 532 and 633 nm to determine the optimum exposure that gives maximum effi...
The use of volume and phase holographic elements in the design of photovoltaic solar concentrators has become very popular as an alternative solution to refractive systems, due to their high efficiency, low cost and possibilities of building integration. Angular and chromatic selectivity of volume holograms can affect their behavior as solar concen...
A building integrated holographic concentrating photovoltaic-thermal system has been optically and energetically simulated. The system has been designed to be superimposed into a solar shading louvre; in this way the concentrating unit takes profit of the solar altitude tracking, which the shading blinds already have, to increase system performance...
The use of holographic optical elements for solar energy applications has increased interest in the recent years because of their potential to reduce production cost, their ability to select certain bandwidths of the solar spectrum and their suitability for architectural integration. Among the different typologies of holograms, volume holograms are...
Volume Holographic Optical Elements (HOEs) present interesting characteristics for photovoltaic applications as they can select spectrum for concentrating the target bandwidth and avoiding non-desired wavelengths, which can cause the decrease of the performance on the cell, for instance by overheating it. Volume HOEs have been recorded on Bayfol HX...
A photograph of a white-light vortex obtained by means of volume phase holographic optical elements that allow creating achromatic vortices for a wide spectral range is shown. The elementshave been recorded in dichromated gelatin and have a high damage threshold, so they are suitable for the generation of optical vortices with ultraintense femtosec...
A ray tracing algorithm is developed to analyze the energy performance of transmission and phase volume holographic lenses that operate with broadband illumination. The agreement between the experimental data and the theoretical treatment has been tested. The model has been applied to analyze the optimum recording geometry for solar concentration a...
We simulate the local chromatic and angular selectivity of two different recording geometries of volume and phase holographic cylindrical lenses, studying the dependence on the aperture of the lens.
A compound holographic optical element to generate achromatic vortices with high efficiency, based on the combination of two volume phase holograms, is designed and constructed. This element is compact and easy to align. It has high damage threshold, so it can be used with ultraintense laser pulses.
We have designed and developed a pulse compressor with volume transmission holographic gratings to be implemented in post-compression
experiments based on filamentation in gases. Pulse compression down to 13fs has been demonstrated. The gratings have been
recorded in commercial PFG-04 dichromated gelatin emulsions with a recording wavelength of 532...
In this work we carried on the recording of holographic stereograms with horizontal parallax from synthetic images taken from tridimensional virtual objects. To be able to automate the process, we developed the complete system including the obtaining of the images and the total control of the needed system to automate the process. We did not find i...
We characterize Slavich PFG-04 dichromated gelatin plates to make transmission volume holographic elements recorded with a 532 nm laser source, obtaining high efficiency gratings with a high signal to noise ratio. The linear dynamic range of the material is studied by measuring the efficiency of multiplexed gratings. Results obtained are applied to...
In this work we design and construct a pulse compressor with volume transmission holographic gratings, to compensate
the second order dispersion in femtosecond laser pulses emitting at 794 nm with a spectral broadband of 10 nm. The
gratings (730 lines/mm) are recorded in PFG-04 dichromated gelatine emulsion with a wavelength of 532 nm, reaching
eno...
The aim of this work was the design and construction of an anamorphic white light optical processor with holographic lenses. The recording material, silver halide emulsions PFG-01, was characterized and its efficiency and dynamic range was studied. We recorded simple and partitioned field holographic lenses on these emulsions, as well as astigmatic...
In this work we characterize Slavich PFG‐04 dichromated gelatin as holographic recording material to record transmission optical elements. First the behavior of the diffraction efficiency as a function of exposure is studied. The plates were exposed with a green NdYVO4 laser operating at λ = 532 nm (with an output power of 6.00 W). Antihalation pla...
An anamorphic white light Fourier processor is used to analyse PIV photographs. The processor is constructed using two holographic cylindrical lenses and one refractive cylindrical lens arranged to correct the longitudinal and lateral chromatic dispersion. By measure the period of the fringes that appear on Fourier plane we can found one component...
An experimental method for the production of high power optical vortices by using volume phase holographic plates is presented.
Experiments in air, N2 and Ar have been performed as an example of the method’s potential, observing non-linear effects and filamentation. Theoretical
calculations support the conclusions.
Two anamorphic and achromatic Fourier processors were designed and constructed using diffractive and refractive cylindrical lenses. The diffractive lenses are holographic lenses recorded on silver halide material. In both processors the achromatic one-dimensional Fourier transform plane was obtained with two holographic lenses and one refractive cy...
We present the design of holographic spherocylindrical lenses composed by two biaxial holographic elements. These compound lenses exhibit smaller aberrations than biaxial holographic lenses while maintaining high efficiency and a high signal-to-noise ratio. We develop a theoretical expression for the third-order aberrations in these systems making...
We design and construct anamorphic holographic lenses composed by two volume holographic elements. We study their efficiency and their capability to perform the multi-channel Fourier transformation. We test the behavior of an anamorphic optical processor constructed with these holographic lenses.
An optical method for generating a reference signal for an incremental displacement measurement system is proposed. We achieved this zero reference signal by comparing two speckle patterns arriving from two symmetric diffusers, which are used as natural random codes that are identical only when the reading head is located equidistantly between the...
Partitioned-field uniaxial volume holographic lenses increase the image fields of holographic volume lenses that are limited by angular selectivity. The efficiency and aberrations of one of these systems consisting of two overlapping uniaxial noncentered lenses were reported previously [Appl. Opt. 38, 4011 (1999)]. In the present study we present t...
Partitioned-field uniaxial volume holographic lenses increase the image fields of holographic volume lenses that are limited by angular selectivity. The efficiency and aberrations of one of these systems consisting of two overlapping uniaxial noncentered lenses were reported previously [Appl. Opt. 38, 4011 (1999)]. In the present study we present t...
In this work we study the feasibility of using silver halide sensitized gelatin based on PFG-01 (Slavich) emulsions to construct uniaxial compound lenses. This processing is able to introduce variations in the thickness and refractive index of the emulsion. We prove that these changes are not sufficient to provide the observed variations in Bragg c...
The efficiency and aberration of partitioned-field uniaxial volume holographic compound lenses are theoretically and experimentally studied. These systems increase the image fields of holographic volume lenses, limited by the angular selectivity that is typical of these elements. At the same time, working with uniaxial systems has led to a decrease...
In revolution-symmetrical optical systems design, it is usual to extract information of aberrations from ray tracing of selected rays. In this work, we generalise the relationship between ray aberration and wave aberration for a biaxial imaging system that includes holographic optical elements (HOEs); both for conjugate planes perpendicular to opti...
We describe the basis for the ray tracing procedure in aspheric holographic optical elements to
include the effect of non-spherical construction waves on local grating.
We propose an algorithm to determine the effect of plane-parallel
glass-plate substrate on local grating of holographic lenses. The effectiveness
of the algorithm is demonstrated...
A SHSG procedure to register volume phase holograms in Kodak 131 plates
is presented. We analyze the influence on the diffraction efficiency of
the developing step and the temperature of the bleaching bath of usual
SHSG processes. Applying a simple 12 steps process to form phase
transmission holograms developing with D-19, bleaching with R-10 at 70...
A general study of third-order aberrations of aspheric
holographic optical elements is described, including the
effect of wavefront deviation from construction waves on the total
aberration. Third-order aberration coefficients for a plane
parallel glass plate referred to a general case in which the
optical axes are not normal to the plate surfaces...
The angular selectivity inherent to volume holograms limits the imaged field in holographic optical systems with high efficiency. We describe three systems designed to overcome this problem based on the recording of gratings with different recording planes. A fourth solution, using gratings recorded with different object points sources and plane wa...
The angular selectivity inherent to volume holograms limits the imaged field in holographic optical systems with high efficiency. We describe three systems designed to overcome this problem based on the recording of gratings with different recording planes. A fourth solution, using gratings recorded with different object points sources and plane wa...
Arrangements are described for the recording of volume holograms with two sections that, when stacked together, work as uniaxial centered lenses and allow one to solve the problem of angular selectivity in the imaging of wide objects. The performance of such systems is examined qualitatively, and suggestions aimed at improving these designs are pro...
Kogelnik’s coupled wave theory is used to obtain the relative
phase and directions of the coupled waves at the output of a planar volume
grating. This allows us to obtain the energy coupling on a planar volume grating
when it is illuminated by two waves related by diffraction. We illustrate this
coupling with a two grating beamsplitter that splits...
Desarrollo de una formulación completa del comportamiento como sistemas formadores de imagen de lentes holográficas biaxiales, tanto en la aproximación del tercer orden como para el trazado de rayos, incluyendo el efecto de pupilas fuera de las lentes y de las láminas de vidrio soporte de la emulsión holográfica. Se ha extendido el estudio a sistem...