Información del autor
Autor Calvo Padilla, María Luisa |
Documentos disponibles escritos por este autor (133)
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Martínez Matos, Óscar ; Cheben, Pavel ; Schmid, Jens H. ; Bogdanov, Alexei L. ; Calvo Padilla, María Luisa ; Delâge, André ; Densmore, Adam ; Janz, Siegfried ; Lamontagne, Boris ; Lapointe, Jean ; Post, Edith ; Powell, Ian ; Rodrigo Martín-Romo, José Augusto ; Waldron, Phillip ; Xu, Dan-Xia | IEEE | 2006We present several new concepts to extend the capabilities of arrayed waveguide grating spectrometers. Strong lateral mode confinement wavegaide structure in the focal plane is used to increase resolution, a Michelson-type AWG spectrometer can i[...]texto impreso
The authors present a mathematically exact formulation of the initial field striking the aperture of an absorbing optical waveguide, via an integral equation description. An analysis of the residual scattering by the waveguide is presented. Beca[...]texto impreso
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Weigand Talavera, Rosa María ; Calvo Padilla, María Luisa ; Gonzalo Fonrodona, Isabel ; Villafranca Velasco, Aitor | 2017-01Se generaran topografías FDTD en sistemas fotónicos para ejemplificación en clase por parte del profesor, realización de trabajos en grupo, realización de prácticas de laboratorio, autoaprendizaje del alumno y Trabajos Fin de Grado y Máster.texto impreso
Rodrigo Martín-Romo, José Augusto ; Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa | Elsevier Science BV | 2007-10-15Gyrator transform is a new tool for manipulation of two-dimensional signals such as images or laser beam profiles. Here we demonstrate various applications of the gyrator transform for image processing. Several aspects such as noise reduction, f[...]texto impreso
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Carreras Béjar, Carmen ; Chevalier del Río, Margarita ; Calvo Padilla, María Luisa | SPIE--The International Society for Optical Engineering | 1984In this paper, we present a theoretical model for the transmission function of a biological cell. Three different cases have been considered: a) Real transmission function, b) Pure phase Object, c) Mixed case where both, real and complex terms a[...]texto impreso
Varela Vargas, Alberto J. ; Calvo Padilla, María Luisa | Spie-Soc Photo-Optical Instrumentation Engineers | 1995-04We present a comparative study between two experimental methods to determine the modulation transfer function (MTF) of a hololens system. The two hololenses were previously recorded and tested for filtering pseudocolor. In the first method we us[...]texto impreso
Martínez Matos, Óscar ; Calvo Padilla, María Luisa ; Cheben, Pavel ; Janz, Siegfried ; Rodrigo Martín-Romo, José Augusto ; Xu, Dan-Xia ; Delâge, André | IEEE - Inst. Electrical Electronics Engineers Inc. | 2006-03The authors propose a new wavelength-dispersive principle based on waveguide group-index modification and apply this principle in a new type of arrayed waveguide dispersive element based on modified group index. The element is composed by an arr[...]texto impreso
Villafranca Velasco, Aitor ; Bock, Przemek J. ; Cheben, Pavel ; Calvo Padilla, María Luisa ; Schmid, Jens H. ; Lapointe, Jean ; Xu, Dan-Xia ; Janz, Siegfried ; Delâge, André | The Institution of Engineering and Technology (IET) | 2012-06-07The fabrication and experimental characterisation of a two-stage bandpass filter based on curved waveguide sidewall gratings is reported for the silicon-on-insulator platform. At each cascaded filtering stage, the spectral components of the inpu[...]texto impreso
Martínez Matos, Óscar ; Rodrigo Martín-Romo, José Augusto ; Alieva, Tatiana Krasheninnikova ; Cámara, Alejandro ; Cheben, Pavel ; Calvo Padilla, María Luisa | The Optical Society Of America | 2011-03-28In this work, we propose a robust and versatile approach for the characterization of the complex field amplitude of holographically generated coherent-scalar paraxial beams. For this purpose we apply an iterative algorithm that allows recovering[...]texto impreso
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Guibelalde del Castillo, Eduardo ; Calvo Padilla, María Luisa | Spie-Soc Photo-Optical Instrumentation Engineers | 1987-06A new integral equation is presented and solved by a matrix method based on iterative procedures to obtain information about the transmission and reflection of light (scalar field) in inhomogeneous media. The method, which may be applied to a wi[...]texto impreso
The physical possibility of neutron fibres, proposed in a previous paper, is reviewed briefly. Further possibilities and results are reported specifically about : (a) magnetized fibres, (b) propagation modes in homogeneous circular fibres (upper[...]texto impreso
In this work we present a general formulation of the corrections to the Raman-Nath approximation for the diffracted field by a volume hologram, based on integral equations. An approximate analytic expression is given for the first correction. Nu[...]texto impreso
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Guibelalde del Castillo, Eduardo ; Calvo Padilla, María Luisa | Kluwer Academic Publishers | 1986-05A coupled-wave analysis is given for a mixed hologram grating. The effect of spatial dephasing between the absorption and phase grating which was previously presented in transmission gratings is now developed for reflection ones. The effect is p[...]texto impreso
Fernández Álvarez-Estrada, Ramón ; Calvo Padilla, María Luisa | SPIE--The International Society for Optical Engineering | 1983A general integral equation for the total scattered magnetic field is presented. Thus,the coupling phenomena between N identical dielectric waveguides can be interpreted as a multiple scattering process. The application to the case of two identi[...]texto impreso
Bock, Przemek J. ; Cheben, Pavel ; Schmid, Jens H. ; Villafranca Velasco, Aitor ; Delâge, André ; Janz, Siegfried ; Xu, Dan-Xia ; Lapointe, Jean ; Hall, Trevor J. ; Calvo Padilla, María Luisa | The Optical Society Of America | 2012-08-27We experimentally demonstrate a new type of waveguide multiplexer device designed for silicon photonics, with a crosstalk level as low as -35 dB and an operational wavelength range of 300 nm. A compact device footprint of only 100 x 160 µm2 offe[...]texto impreso
Rodrigo Martín-Romo, José Augusto ; Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa ; Davis, Jeffrey A. | Taylor and Francis Ltd. | 2005-12-15The paper reports studies, both experimental and using numerical simulation, of the Fresnel diffraction by recently introduced fractal zone plates associated with triadic and quintic Cantor sets. The evolution of the intensity patterns at planes[...]texto impreso
The interaction and diffraction of a classical electromagnetic wave by a thin slab characterised by a periodic dielectric permeability is studied rigorously, thereby completing previously existing studies. New integral equations for the inductio[...]texto impreso
Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa | SPIE--The International Society for Optical Engineering | 2003The Fresnel and Fraunhofer diffraction on the regular structures generated by the multiplicative iterative procedures is considered. It is proved that the iterative procedure of field construction is preserved during Fresnel diffraction, meanwhi[...]texto impreso
Martínez Matos, Óscar ; Calvo Padilla, María Luisa ; Rodrigo Martín-Romo, José Augusto ; Cheben, Pavel ; Monte Muñoz de la Peña, Francisco del | American Institute of Physics | 2007-10-01We report results on the temporal evolution of the diffraction efficiency of volume holographic gratings recorded in a photopolymer glass incorporating Zr-based high refractive index species (HRIS) at molecular level. We record high spatial freq[...]texto impreso
Sanz, Inmaculada ; Calvo Padilla, María Luisa ; Chevalier del Río, Margarita | SPIE--The International Society for Optical Engineering | 1998The presence of degraded or soft edges on a scene or digital image may cause ambiguities in depth perception(1,2). This kind of edges has been analyzed by introducing a mathematical model to digitally implement a large category of degraded edges[...]texto impreso
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We present a formalism based upon dynamic programming (DP), to characterize light propagation in particular GRIN (gradient index) media by analyzing ray trajectories associated with skew-type rays. We study the conditions for the formation of pe[...]texto impreso
Calvo Padilla, María Luisa ; Enoch, Jay M. jmenoch@socrates.berkeley.edu | Lippincott Williams & Wilkins | 2003-10We discuss many aspects of a reproduction of a formal painting from the XVIth century. It is a portrait of Viceroy of New Spain Luis de Velasco, El Joven or Hijo (son—see text), found at the Museum of the Pecos National Monument (near Pecos and [...]texto impreso
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Manzanares Ituarte, Ana ; Calvo Padilla, María Luisa ; Chevalier dl Río, Margarita ; Lakshminarayanan, Vasudevan | Elsevier Science BV | 1998-12We discuss a formalism to characterize degraded edge images formed in a diffraction limited system (with circular pupil of unit radius) under conditions of incoherent illumination. We introduce a novel definition of degraded edges and consider t[...]texto impreso
Fernández Álvarez-Estrada, Ramón ; Calvo Padilla, María Luisa | American Institute of Physics | 1980The scattering of electromagnetic waves by an infinite dielectric cylinder with variable dielectric permeability presents, in general, certain mathematical difficulties regarding the construction of rigorous solutions. We give a new divergencele[...]texto impreso
Kundikova, Nataliya D. ; Ryzhkova, A. V. ; Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa ; Rodrigo Martín-Romo, José Augusto | Maik Nauka, Interperiodica, Springer-Verlag | 2008-05The effect of the Gaussian beam width on the focusing properties of the chainlike Gaussian beam formed upon diffraction of laser radiation on a binary amplitude mask is studied. It is found that a decrease in the Gaussian beam width increases th[...]texto impreso
Martínez Matos, Óscar ; Calvo Padilla, María Luisa ; Cheben, Pavel ; Monte Muñoz de la Peña, Francisco del ; Rodrigo Martín-Romo, José Augusto | American Physical Society | 2006-08-25We report observations of periodic oscillatory behavior of the angular selectivity, near the Bragg angle, in volume holographic gratings recorded in a new photopolymerizable glass with high refractive index modulation. We have detected the prese[...]texto impreso
Rodrigo Martín-Romo, José Augusto ; Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa | Optical Society of America | 2007-10The gyrator transform (GT) promises to be a useful tool in image processing, holography, beam characterization, mode transformation, and quantum information. We introduce what we believe to be the first flexible optical experimental setup that p[...]texto impreso
The multiple scattering of classical electromagnetic waves byN fixed dielectric obstacles is studied by using a new Green’s function introduced in a previous paper. The use of the new Green’s function leads us to show that the kernels of the bas[...]texto impreso
Martínez Matos, Óscar ; Hernández Garay, María de la Paz ; Izquierdo, J. G. ; Vaveliuk, Pablo ; Bañares Morcillo, Luis ; Calvo Padilla, María Luisa | American Institute of Physics | 2014-07-28A procedure to characterize the induced damage and the incubation effects in volume transmission gratings under femtosecond laser pulse train illumination is presented. It was also developed a formalism that explains the damage processes. Our pr[...]texto impreso
Martínez Matos, Óscar ; Hernández Garay, María de la Paz ; González Izquierdo, Jesús ; Calvo Padilla, María Luisa ; Vaveliuk, Pablo ; Cheben, Pavel ; Bañares Morcillo, Luis | Optical Society of America | 2011-01-17The majority of the applications of ultrashort laser pulses require a control of its spectral bandwidth. In this paper we show the capability of volume phase holographic gratings recorded in photopolymerizable glasses for spectral pulse reshapin[...]texto impreso
Guibelalde del Castillo, Eduardo ; Calvo Padilla, María Luisa | The Optical Society Of America | 1982We present a theoretical model for the filter function of a holographic grating when the absorption coefficient of the photomaterial is nonnegligable. In this case there is also modulation in the conductivity, which leads to a cosinusoidal funct[...]texto impreso
Rodrigo Martín-Romo, José Augusto ; Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa | American Institute of Physics (AIP) | 2006In this work we propose a flexible symmetric configuration for the separable fractional FT composed by three generalized lenses. The distances between the lenses are fixed. The fractional angles are acieved by means of lens rotations.texto impreso
Molina de la Peña, Ignacio ; Calvo Padilla, María Luisa ; Álvarez Estrada, Ramón F. | Taylor & Francis Ltd | 2019-06-22We studied the propagation of slow neutrons and their waveguiding properties in certain suitable thin films where Ti and Si play a key role, having in mind their possible use in Boron Neutron Capture Therapy (BNCT) of small tumors. In PBSi2017 w[...]texto impreso
Calvo Padilla, María Luisa ; Alieva, Tatiana Krasheninnikova ; Bastiaans, Martin J. ; Rodrigo Martín-Romo, José Augusto ; Rodríguez Merlo, D. | SPIE--The International Society for Optical Engineering | 2004We present a short overview on the application of fractional cyclic and linear canonical transformations to optical signal processing and dedicate some of the discussions to the particular features found in the fractional Fourier transform domain.texto impreso
Davis, Jeffrey A. ; Ramirez, Laura ; Rodrigo Martín-Romo, José Augusto ; Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa | Alan E. Willner, University of Southern California | 2004-06-15We report the first experimental results, to our knowledge, with fractal zone plates implemented in a liquid-crystal display. Our results largely agree with theory for the axial irradiance distribution of these lenses. The dependence of the shap[...]texto impreso
Davis, Jeffrey A. ; Sigarlaki, Sean Paul ; Craven, Julia M. ; Calvo Padilla, María Luisa | The Optical Society Of America | 2006-02-20We report on a Fourier series approach that predicts the focal points and intensities produced by fractal zone plate lenses. This approach allows us to separate the effects of the fractal order from those of the lens aperture. We implement these[...]texto impreso
Bastiaans, Martin J. ; Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa | Hindawi Publishing Corporation | 2005-07-01We review the progress achieved in optical information processing during the last decade by applying fractional linear integral transforms. The fractional Fourier transform and its applications for phase retrieval, beam characterization, space-v[...]texto impreso
In this study the general algorithm for the fractionalization of the linear cyclic integral transforms is established. It is shown that there are an infinite number of continuous fractional transforms related to a given cyclic integral transform[...]texto impreso
Rodrigo Martín-Romo, José Augusto ; Rodríguez Merlo, Daniel ; Calvo Padilla, María Luisa ; Alieva, Tatiana Krasheninnikova | Maik Nauka, Interperiodica, Springer-Verlag | 2003-07Experimental results are presented for light diffraction under the Fresnel regime by two types of fractal gratings: triadic Cantor bars and Vicsek fractals. It is shown that the evolution of the diffraction patterns in the Fresnel regions reveal[...]texto impreso
Rodrigo Martín-Romo, José Augusto ; Cheben, Pavel ; Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa ; Scott, Alan ; Solheim, Brian ; Xu, Dan-Xia ; Delâge, André | The Optical Society Of America | 2007-12-10We present an analysis of Fourier-transform arrayed waveguide gratings in the Fresnel diffraction regime. We report a distinct spatial modulation of the interference pattern referred to as the Moire-Talbot effect. The effect and its influence in[...]texto impreso
Calvo Padilla, María Luisa ; Molina de la Peña, Ignacio ; Álvarez Estrada, Ramón F. | Spie-Int Soc Optical Engineering | 2019Neutron optics is the branch of quantum physics devoted to the study of the optical properties of slow neutrons and their behavior as wave-particles. Slow neutrons beams (with typical energy the order of 0.025 eV, known as thermal neutrons, and [...]texto impreso
Lakshminarayanan, Vasudevan ; Calvo Padilla, María Luisa | Spie-Soc Photo-Optical Instrumentation Engineers | 1991-10A systematic procedure for calculating the general transfer function of a cascaded linear optical system working under the Fresnel regime is presented. The validity of neglecting the quadratic phase factors is also discussed. For the case of inh[...]texto impreso
Rodrigo Martín-Romo, José Augusto ; Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa | The International Society for Optical Engineering (SPIE) | 2006Wide application of the laser beams in science, technology and biomedicine demands the generation of the beams with desirable structure. In particular for optical trapping the beams with high transversal gradient of intensity distribution or dou[...]texto impreso
Martínez Matos, Óscar ; Rodrigo Martín-Romo, José Augusto ; Hernández Garay, María de la Paz ; Izquierdo González, Jesús ; Weigand Talavera, Rosa María ; Calvo Padilla, María Luisa ; Cheben, Pavel ; Vaveliuk, Pablo ; Bañares Morcillo, Luis | The Optical Society Of America | 2010-03-01We present an approach to generate paraxial laser beams with arbitrary spatial distribution in the femtosecond time regime. The proposed technique is based upon a pair of volume phase holographic gratings working in parallel arrangement. It expl[...]texto impreso
Rodrigo Martín-Romo, José Augusto ; Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa | The Optical Society Of America | 2007-03-05In this work we formulate the main properties of the gyrator operation which produces a rotation in the twisting (position-spatial frequency) phase planes. This transform can be easily performed in paraxial optics that underlines its possible ap[...]texto impreso
This paper presents a high efficiency holographic coupler design for telecommunication purposes. It is based on the eikonal approach to diffracted field analysis and on the coupled wave analysis for gaussian beam in generalized coordinate.texto impreso
Florja?czyk, Miroslaw ; Villafranca Velasco, Aitor ; Cheben, Pavel ; Calvo Padilla, María Luisa ; Bock, Przemek J. ; Delâge, André ; Schmid, Jens H. ; Lapointe, Jean ; Janz, Siegfried ; Xu, Dan-Xia ; Vachon, Martin | IEEE-Inst Electrical Electronics Engineers Inc. | 2013We report a spatial heterodyne Fourier-transform spectrometer consisting of an array of Mach-Zehnder interferometers (MZI) implemented in silicon microphotonics. Optical path differences between the MZI arms increase linearly along the array, ge[...]texto impreso
Villafranca Velasco, Aitor ; Cheben, Pavel ; Bock, Przemek J. ; Schmid, Jens H. ; Delâge, André ; Lapointe, Jean ; Janz, Siegfried ; Calvo Padilla, María Luisa ; Xu, Dan-Xia ; Florja?czyk, Miros?aw ; Vachon, Martin | The Optical Society Of America | 2013-03-01We report a stationary Fourier-transform spectrometer chip implemented in silicon microphotonic waveguides. The device comprises an array of 32 Mach-Zehnder interferometers (MZIs) with linearly increasing optical path delays between the MZI arms[...]texto impreso
Based on a previous model describing the behavior of a holocoupler/fiber optic device, we develop a new model for a holocoupler/GRIN lens system and analyze the conditions for the coupling to hold and the requirements of the coupled signaltexto impreso
Pedraza Velasco, María Lourdes de ; Calvo Padilla, María Luisa | SPIE--The International Society for Optical Engineering | 1989The interconnection problems in the use of optical fibers for signal transmission is a very active area of research involving several fields such as optical communication techniques and holography. Various authors have studied the efficiency of [...]texto impreso
Pedraza Velasco, María Lourdes de ; Calvo Padilla, María Luisa | The Optical Society Of America | 1989-06-01A mathematical model for describing a holographic coupler–optical fiber system is considered. The object wave to be recorded in the hologram is assumed to be a polarized wave which is scattered by the optical fiber. In the reconstruction the opt[...]texto impreso
Martínez Matos, Óscar ; Rodrigo Martín-Romo, José Augusto ; Vaveliuk, Pablo ; Calvo Padilla, María Luisa | Optical Society of America | 2011-02-15We propose a spectrum analyzer based on the properties of a hologram recorded with the field transmitted by a Fabry-Perot etalon. The spectral response of this holographic Fabry-Perot spectrometer (HFPS) is analytically investigated in the parax[...]texto impreso
Hernández Garay, María de la Paz ; Martínez Matos, Óscar ; González Izquierdo, Jesús ; Calvo Padilla, María Luisa ; Cheben, Pavel ; Bañares Morcillo, Luis | Society of Photo-Optical Instrumentation Engineers (SPIE) | 2011We present the capability of the holographic gratings implemented in photopolymerizable glasses to be applied in spatial and spectral manipulation of femtosecond laser pulses. For this purpose we used volume phase holographic gratings recorded b[...]texto impreso
Guibelalde del Castillo, Eduardo ; Calvo Padilla, María Luisa | Butterworth - Heinemann Ltd. | 1988-06The transition from the Raman-Nath to a Bragg regime for holographic grating diffracted fields is studied using a new integral equation and Fourier transform techniques. Analytical and numerical studies are presented and evaluated.texto impreso
Calvo Padilla, María Luisa ; Alieva, Tatiana Krasheninnikova | Maik Nauka, Interperiodica, Springer-Verlag | 2003-07Image reconstruction from amplitude-only and phase-only data in the fractional Fourier domain applying the inverse fractional Fourier transform is analyzed on the examples of perfect edges of different contrasts and real-world image.texto impreso
The importance of the amplitude and phase in the fractional Fourier transform (FT) domain is analyzed on the basis of the rectangular signal and the real-world image. The quality of signal restoration from only the amplitude or from only the pha[...]texto impreso
The spatial impulse response of a single variable-cross-section photoreceptor has been characterized assuming the incoming radiation to be an initial field propagating under confinement conditions inside the receptor. By application of Fourier a[...]texto impreso
Carreras Béjar, Carmen ; Calvo Padilla, María Luisa ; Chevalier del Río, Margarita | SPIE--The International Society for Optical Engineering. | 1985In preceding works, a theoretical model has been introduced for the transmission function of a biological cell, in which the physical effects of the three transmission functions for the cytoplasm, the nucleus and the cellular membrane have been [...]texto impreso
We consider a general class of inhomogeneous dielectric slabs, where the dielectric permittivity (l) is assumed to depend on the frequency (y) at each position, through the Kramers-Krönig dispersion relation. The physical basis for this assumpti[...]texto impreso
We study monomode slab and cylindrical waveguides, in which the dielectric permittivity l has both a graded spatial variation and finite discontinuities at the boundaries. New integral equations for the H-type propagation mode in the slab and fo[...]texto impreso
An exact formulation of the electromagnetic field striking an optical waveguide is presented and compared with the decomposition relationship used in the literature. The expression for the critical angle is derived as a natural consequence of th[...]texto impreso
We present here numerical estimates of the density and flux of energy based on physical parameters associated with the absorption properties of certain types of absorbing optical waveguides. These results are based on a theoretical formalism est[...]texto impreso
Alieva, Tatiana Krasheninnikova ; Rodrigo Martín-Romo, José Augusto ; Calvo Padilla, María Luisa | American Institute of Physics (AIP) | 2007We introduce the gyrator transform which produces a rotation of two-dimensional signal in phase space. Main properties of this transform are considered. The flexible optical set up for gyrator transform experimental implementation is discussed. [...]texto impreso
We apply techniques of optimal-control theory, namely, the methods of dynamic programming, to the problem of light propagation in optical waveguides. This formulation is equivalent to the resolution of an eikonal equation. We illustrate this opt[...]texto impreso
Calvo Padilla, María Luisa ; Enoch, Jay M. ; Lakshminarayanan, Vasudevan ; Limeres, J. | The Optical Society Of America | 2003-07We develop a computational method for calculating the spatial profile of the electromagnetic field after scattering by an array of waveguides. Our formalism is very general and includes chromatic dependence, the influence of the array arrangemen[...]texto impreso
Manzanares Ituarte, Ana ; Calvo Padilla, María Luisa ; Chevalier del Río, Margarita ; Lakshminarayanan, Vasudevan | The Optical Society Of America | 1997-07-01A revised formulation of the image Light distribution of an incoherent line source proposed by Steel [Rev. Opt. 31, 334-340 (1952)] is presented. Analytical and numerical results based on this new representation are given. We explicitly show tha[...]texto impreso
Since the last decades, cell phones have become increasingly popular and are nowadays ubiquitous. New generations of cell phones are now equipped with text messaging, internet, and camera features. They are now making their way into the classroo[...]texto impreso
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Rodrigo Martín-Romo, José Augusto ; Caravaca Aguirre, Antonio Miguel ; Alieva, Tatiana Krasheninnikova ; Cristóbal Pérez, Gabriel ; Calvo Padilla, María Luisa | The Optical Society Of America | 2011-03-14Three-dimensional microparticle movements induced by laser beams with a funnel- and tubular pod-like structure, in the neighbourhood of the focal plane of an optical trapping setup, are experimentally studied. The funnel and pod beams constructe[...]texto impreso
We present a general formulation for multiple scattering of classical electromagnetic waves by volume gratings. Fujiwara's electron multiple scattering theory is modified and extended to the case of both, the transmission and the reflection geom[...]texto impreso
Fernández Álvarez-Estrada, Ramón ; Calvo Padilla, María Luisa | Pergamon-Elsevier Science Ldt | 2004-11We summarize previous researches regarding neutron guides of small transverse cross-section (neutron fibres), smaller than those of the standard hollow guides and collimators employed currently. Those studies may not be widely known in the neutr[...]texto impreso
For pt.I see ibid., vol.17, p.475 (1984). The possible confined propagation of slow (thermal) neutrons along cladded waveguides of small cross section (fibres) is studied, in order to improve a previously published analysis. Quite suitable possi[...]texto impreso
The authors study confined propagation of slow (thermal) neutrons along (non-hollow) solid fibres made of certain elements (Ti, Mn, ...) such that amplitude for the low-energy nuclear scattering of neutrons on them be negative. Geometrical optic[...]texto impreso
The confined propagation of slow neutrons along waveguides of a small cross section (fibres), discussed theoretically some time ago and demonstrated experimentally by other authors later, is analysed further. Motivated by those experiments, a th[...]texto impreso
Neutron waveguides in neutron optics: Green's functions formalism with Dirichlet boundary conditions
Molina de la Peña, Ignacio ; Calvo Padilla, María Luisa ; Álvarez Estrada, Ramón F. | Taylor and Francis Ltd. | 2020-06-06In neutron optics, we analyse the propagation of slow (thermal) neutrons along a semi-infinite waveguide limited by a large repulsive potential (reminding the propagation of light along an optical fibre). We set an ideal case of a straight empty[...]texto impreso
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Martínez Matos, Óscar ; Calvo Padilla, María Luisa ; Cheben, Pavel ; Rodrigo Martín-Romo, José Augusto ; Janz, Siegfried ; Xu, Dan-Xia ; Delâge, André | Elsevier Science BV | 2007-02-01We propose a new type of arrayed waveguide grating (AWG) multiplexer/demultiplexer based on modified group refractive index. This device is composed by an array of straight and parallel waveguides of equal length and each waveguide consist of tw[...]texto impreso
Martínez Matos, Óscar ; Cheben, Pavel ; Calvo Padilla, María Luisa ; Rodrigo Martín-Romo, José Augusto ; Monte Muñoz de la Peña, Francisco del | Society of Photo-Optical Instrumentation Engineers (SPIE) | 2007We report recent results obtained with volume holographic gratings recorded in a new photopolymerisable glass modified with high refractive index species at molecular level. Various not previously observed performances have been achieved for dif[...]texto impreso
Rigorous approximation techniques for the scattering of a classical electromagnetic wave by fixed obstacles are studied. For that purpose, a new Green's function G^T is introduced, which is divergenceless throughout all space and, hence, less si[...]texto impreso
We present a revisited study of the Thompson-Wolf experiment earlier developed in 1957 with the aim to characterize the degree of spatial coherent of a luminous source. We develop further experiments by using laser sources under various modal re[...]texto impreso
Villafranca Velasco, Aitor ; Cheben, Pavel ; Florja?czyk, Miros?aw ; Schmid, Jens H. ; Bock, Przemek J. ; Lapointe, Jean ; Delâge, André ; Janz, Siegfried ; Vachon, Martin ; Calvo Padilla, María Luisa ; Xu, Dan-Xia ; Civiš, Svatopluk | Optical Society of America | 2013-07-01We report a spatial heterodyne Fourier-transform spectrometer implemented with an array of optical fiber interferometers. This configuration generates a wavelength-dependent stationary interferogram from which the input spectrum is retrieved in [...]texto impreso
Carreras Béjar, Carmen ; Chevalier del Río, Margarita ; Calvo Padilla, María Luisa | The Optical Society Of America | 1984In this paper we present a theoretical model for the transmission function of a biological cell. Three different cases are considered: real transmission function, pure phase object, general case, where both real and complex terms are present in [...]texto impreso
Rodrigo Martín-Romo, José Augusto ; Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa | Optical Society of America | 2006-10On the basis of a matrix formalism, we analyze the paraxial optical systems composed by generalized lenses and fixed free-space intervals, suitable for orthosymplectic transformations in phase space. Flexible configurations to perform the attrac[...]texto impreso
Cámara, Alejandro ; Alieva, Tatiana Krasheninnikova ; Rodrigo Martín-Romo, José Augusto ; Calvo Padilla, María Luisa | Society of Photo-Optical Instrumentation Engineers (SPIE) | 2011The application of partially coherent optical beams for imaging, free space communication, random medium analysis requires controlling its mutual intensity. This task can be done using the phase-space tomography method consisting on the reconstr[...]texto impreso
Rodríguez, E. E. ; Zúñiga, H. J. ; Tepichín Rodríguez, Eduardo ; Calvo Padilla, María Luisa | American Institute of Physics (AIP) | 2008A programmable digital circuit typically consists of a microprocessor, a memory device, an input data device and an output data device, with its corresponding communication busses. These devices work following a program which is stored in the me[...]texto impreso
We consider Fresnel and Fraunhofer diffraction on regular structures generated by multiplicative iterative procedures. We prove that the iterative procedure of field construction is preserved during Fresnel diffraction, while the initiator of th[...]texto impreso
Pedraza Velasco, María Lourdes de ; Calvo Padilla, María Luisa | SPIE--The International Society for Optical Engineering | 1990The phase profile of the wave scattered by a GRIN lens has been determined using the eikonal approximation for the scattering amplitude. This wave acts as the object wave in a holographic register to construct a GRIN holocoupler. Different geome[...]texto impreso
Cámara, Alejandro ; Alieva, Tatiana Krasheninnikova ; Rodrigo Martín-Romo, José Augusto ; Calvo Padilla, María Luisa | Optical Society of America | 2009-06We propose a simple approach for the phase space tomography reconstruction of the Wigner distribution of paraxial optical beams separable in Cartesian coordinates. It is based on the measurements of the antisymmetric fractional Fourier transform[...]texto impreso
Cámara, Alejandro ; Alieva, Tatiana Krasheninnikova ; Rodrigo Martín-Romo, José Augusto ; Calvo Padilla, María Luisa | The Optical Society Of America | 2011-07-11We show the adaptation of a multifunctional optical system consisting of two spatial light modulators for the optimal measurement of the Radon-Wigner transform of one-dimensional signals. The proposed Radon-Wigner display allows reconstructing t[...]texto impreso
Permanent holographic storage has been demonstrated in a photopolymerizable organically modified silica glass. The glass was prepared by dispersing a titanocene photoinitiator and a high refractive index acrylic monomer in a porous silica matrix[...]texto impreso
Martínez Matos, Óscar ; Calvo Padilla, María Luisa ; Rodrigo Martín-Romo, José Augusto ; Alieva, Tatiana Krasheninnikova ; Hernández Garay, María de la Paz ; Cheben, Pavel ; Martí Panameño, Erwin José Armando | IEEE | 2009We present an overview of the main properties and the emerging implementations corresponding to a photopolymerizable glass modified with high refractive index species (HRIS) incorporated at molecular level. The study concerns to transmission and[...]texto impreso
Villafranca Velasco, Aitor ; Hernández Garay, María de la Paz ; Calvo Padilla, María Luisa ; Cheben, Pavel ; Monte Muñoz de la Peña, Francisco del | American Institute of Physics | 2011-03-01Three different holographic photomaterials belonging to the class of photopolymerizable glasses have been synthesized using sol-gel techniques, and characterized with the purpose of a comparative study. Their behavior is analyzed in terms of ach[...]texto impreso
Villafranca Velasco, Aitor ; Calvo Padilla, María Luisa ; Cheben, Pavel | American Institute of Physics | 2013-06-21A novel formulation and synthesis method to overcome the thickness limitations in samples of photopolymerizable glasses with high refractive index species is presented. The reported method allows the recording of volume holographic diffraction g[...]texto impreso
The research into new photosensitive materials with advanced performance for holographic applications is an active branch in material science and photonics, still challenging the field. We proposed a new class of volume hologram recording materi[...]texto impreso
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Martíenz Matos, Óscar ; Rodrigo Martín-Romo, José Augusto ; Calvo Padilla, María Luisa ; Cheben, Pavel | The Optical Society Of America | 2009-02-15Polarization properties of transmission volume holographic phase gratings recorded in a photopolymerizable glass modified with high refractive index species are reported. The gratings are recorded by the interference of two parallel s-polarized [...]texto impreso
Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa ; Bastiaans, Martin J. | SPIE--The International Society for Optical Engineering | 2003The main properties of n-th order power filtering in the fractional Fourier domain and its relationship to the differentiation operation are considered. The. application of power filtering for solving the phase retrieval problem is proposed.texto impreso
Bastiaans, Martin J. ; Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa | IOP Publishing | 2002-09-13The main properties of the power filtering operation in the fractional Fourier domain and its relationship to the differentiation operation are considered. The application of linear power filtering for solving the phase retrieval problem from in[...]texto impreso
Rodrigo Martín-Romo, José Augusto ; Alieva, Tatiana Krasheninnikova ; Calvo Padilla, María Luisa | The Optical Society Of America | 2009-03-30A flexible optical system able to perform the fractional Fourier transform (FRFT) almost in real time is presented. In contrast to other FRFT setups the resulting transformation has no additional scaling and phase factors depending on the fracti[...]texto impreso
Mondal, Pronab K. ; Chevalier del Río, Margarita ; Calvo Padilla, María Luisa | SPIE--The International Society for Optical Engineering | 1990We define a resolution criterion for the case of two narrow line images. For doing so, we have considered the two lines as superposition of gradients of two Heaviside step-functions.texto impreso
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Fernández Álvarez-Estrada, Ramón ; Calvo Padilla, María Luisa ; Juncos del Egido, Purificación | Taylor and Francis, Ltd. | 1980The scattering of electromagnetic waves by dielectric cylinders and, in particular, by optical fibres is studied through integral equations. The convergence of the iterations of the integral equations is established under certain conditions. The[...]texto impreso
Pedraza Velasco, María Lourdes de ; Calvo Padilla, María Luisa | The Optical Society Of America | 1993-07-20A mathematical model that describes a fiber-to-fiber holographic connector is presented. We consider both single- and double-image cases for the reconstruction of the second hologram. A comparative study of the two coupling conditions is present[...]texto impreso
We study anisotropic cylindrical dielectric waveguides under the following conditions: (1) their cross section ? has arbitrary shape; (2) the dielectric permittivity tensor ? has discontinuities at the boundaries, as well as a graded spatial var[...]texto impreso
Martínez Matos, Óscar ; Calvo Padilla, María Luisa ; Cheben, Pavel ; Rodrigo Martín-Romo, José Augusto ; Monte Muñoz de la Peña, Francisco del | Maik Nauka, Interperiodica, Springer-Verlag | 2007-12The advances in the sol-gel holographic recording materials, namely in the photopolymerizable compositions and photorefractive glasses, are reviewed. A new sol-gel holographic material is also discussed that exploits diffusion of a high-refracti[...]texto impreso
We present an application of the analysis of light propagation in optical waveguides using the dynamic programming technique. We have obtained results for the transit time light pulse propagated in periodically segmented waveguides. Different se[...]texto impreso
Herrero-Bermello, Alaine ; Villafranca Velasco, Aitor ; Podmore, Hugh ; Cheven, Pavel ; Schmid, Jens H. ; Janz, Siegfried ; Calvo Padilla, María Luisa ; Xu, Dan-Xia ; Scott, Alan ; Lee, Regina | SPIE - International Society for Optical Engineering | 2018Spatial heterodyne Fourier transform (SHFT) spectroscopy is based on simultaneous interferometric measurements implementing linearly increasing optical path differences, hence circumventing the need for mechanical components of traditional Fouri[...]texto impreso
Limeres, J. ; Calvo Padilla, María Luisa ; Lakshminarayanan, Vasudevan ; Enoch, Jay M. | SPIE--The International Society for Optical Engineering | 2003We propose a new stress-sensing technique based upon measurement of light scattering produced by an array of birefringent waveguides. When external; stress is applied to the array of waveguides, their optical properties are modified via the phot[...]texto impreso
Martínez Matos, Óscar ; Vaveliuk, Pablo ; Moraes, Fernando Jorge Sampaio ; Fumeron, Sebastien ; Calvo Padilla, María Luisa | Optical Society of America | 2010-06A q-plate is a stratified medium composed of a uniaxial nematic liquid crystal with an inhomogeneous orientation of the optical axis possessing a topological charge q, which looks promising as a switching device. This work reports an approach to[...]texto impreso
Villafranca Velasco, Aitor ; Hernández Garay, María de la Paz ; Calvo Padilla, María Luisa ; Cheben, Pavel ; Monte Muñoz de la Peña, Francisco del | Society of Photo-Optical Instrumentation Engineers (SPIE) | 2011In this work we analyze the optical quality, performance, and recording mechanism of holographic diffraction gratings recorded in photopolymerizable sol-gel glasses. These classes of holographic photomaterials have various compositions, one of w[...]texto impreso
Cheben, Pavel ; Calvo Padilla, María Luisa ; Belenguer Dávila, Tomás ; Núñez Peral, Armonía | Elsevier Science BV | 1998-03-01A novel method of substrate mode hologram (SMH) design and fabrication is presented. The coupling between a homogeneous plane wave and an arbitrary free propagating wave is achieved via a total internally reflected (TIR) wave. The input slanted [...]texto impreso
Bock, Przemek J. ; Cheben, Pavel ; Villafranca Velasco, Aitor ; Schmid, Jens H. ; Delâge, André ; Florja?czyk, Miros?aw ; Lapointe, Jean ; Xu, Dan-Xia ; Vachon, Martin ; Janz, Siegfried ; Calvo Padilla, María Luisa | Wiley-V C H Verlag Gmbh | 2013-11A planar waveguide Fourier-transform spectrometer with densely arrayed Mach-Zehnder interferometers is demonstrated. Subwavelength gratings are used to produce an optical path difference without waveguide bends. The fabricated device comprises o[...]texto impreso
Se presenta una revisión de las teorías de la difracción de ondas electromagnéticas por redes de volumen. En el enfoque de este trabajo se encuentran las teorías de los siguiente grupos: teorías de ondas acopladaseorías modales, teorías de dispe[...]texto impreso
Moreno Soriano, Ignacio ; Yzuel, María J. ; Calvo Padilla, María Luisa | SPIE - International Society for Optical Engineering | 2018In this work, we review the main activities related to the International Day of Light (IDL) in Spain. We describe the actions of the Spanish Committee for IDL that has been created in Spain, reactivating the Spanish Committee for the Internation[...]texto impreso
In this article we report on the activities in Spain related to the celebration of the International Day of Light (IDL). The Spanish Committee for the IDL was constituted in 2017, as a continuation of the previous Committee for the International[...]texto impreso
Mondal, Pronab K. ; Calvo Padilla, María Luisa ; Chevalier del Río, Margarita ; Lakshminarayanan, Vasudevan | The International Society of Optical Engineering (SPIE) | 1991Resolution criteria for resolving two line images under coherent and incoherent illumination are presented. This technique has been used to interpret psychophysical data obtained from hyperacuity paradigms.texto impreso
Fernández Álvarez-Estrada, Ramón ; Calvo Padilla, María Luisa | Optical Society of America | 1987-04A three-dimensional analysis of bending losses in dielectric optical waveguides is presented. It constitutes a nontrivial generalization of previous two- and three-dimensional studies by other authors. Our analysis is based on homogeneous integr[...]texto impreso
Cámara, Alejandro ; Alieva, Tatiana Krasheninnikova ; Rodrigo Martín-Romo, José Augusto ; Calvo Padilla, María Luisa | The Electromagnetics Academy | 2010The numerical demonstration of the phase-space tomographic reconstruction method of non-separable beams is presented in this contribution. The Wigner distribution of a Laguerre-Gaussian beam is recovered from numerically simulated intensity meas[...]texto impreso
We introduce a coupling model to describe the geometry conversion in various wave fronts diffracted by a holocoupler recorded with two different Gaussian beams. We conjecture the possibilities for using the proposed device as a beam corrector.texto impreso
Villafranca Velasco, Aitor ; Calvo Padilla, María Luisa ; Cheben, Pavel ; Ortega Moñux, Alejandro ; Schmid, Jens H. ; Alonso Ramos, Carlos ; Molina Fernández, Íñigo ; Lapointe, Jean ; Vachon, Martin ; Janz, Siegfried ; Xu, Dan-Xia | IEEE | 2012We demonstrate an ultracompact polarization mode converter based on a silicon-on-insulator waveguide with two longitudinal subwavelength trenches. An extinction ratio of 16 dB at 1.5 ?m is achieved for a device length of 10 ?m.texto impreso
Villafranca Velasco, Aitor ; Calvo Padilla, María Luisa ; Cheben, Pavel ; Ortega Moñux, Alejandro ; Alonso Ramos, Carlos Alberto ; Molina Fernández, Íñigo ; Lapointe, Jean ; Vachon, Martin ; Janz, Siegfried ; Xu, Dan-Xia | The Optical Society Of America | 2012-02-01The design and fabrication of an ultracompact silicon-on-insulator polarization converter is reported. The polarization conversion with an extinction ratio of 16 dB is achieved for a conversion length of only 10 mu m. Polarization rotation is ac[...]texto impreso
Monte Muñoz de la Peña, Francisco del ; Martínez Matos, Óscar ; Rodrigo Martín-Romo, José Augusto ; Calvo Padilla, María Luisa ; Cheben, Pavel | Wiley-V C H Verlag Gmbh | 2006-08-04Improved performance of volume holographic sol-gel materials-refractive index modulations in the 10^2 range, diffraction efficiencies near 100 %, and low levels of noise scattering-are reported that arise from the incorporation of Zr-based high [...]texto impreso
The theoretical model for an off-Bragg on-axis conversion between a Gaussian beam with cylindrical phase function and a plane wave by a volume aperiodic nonplanar inhomogeneous holographic grating is presented. A two-wave first-order coupled-wav[...]texto impreso
We present a coupled-wave-analysis-based treatment for a wave-front conversion problem between a Gaussian beam with a cylindrical phase and a plane wave for a two-dimensional on-axis geometry. A coupled-wave approach to the multiple-scattering p[...]texto impreso
Rodrigo Martín-Romo, José Augusto ; Alieva, Tatiana Krasheninnikova ; Cristóbal Pérez, Gabriel ; Calvo Padilla, María Luisa | The Optical Society Of America | 2011-09-12We present a fast and robust non-interferomentric wavefield retrieval approach suitable for imaging of both amplitude and phase distributions of scalar coherent beams. It is based on the diversity of the intensity measurements obtained under con[...]texto impreso
Martínez Matos, Óscar ; Calvo Padilla, María Luisa ; Cheben, Pavel ; Delâge, André ; Janz, Siegfried ; Xu, Dan-Xia | Society of Photo-Optical Instrumentation Engineers (SPIE) | 2004We propose a modified arrayed waveguide grating (AWG) demultiplexer formed by an array of parallel ridge waveguides of equal length fabricated in silicon-on-insulator (SOI). Each waveguide contains two sections with different widths. The lenghts[...]