Person:
Alda Serrano, Javier

First Name

Javier

Last Name

Alda Serrano

URI

https://hdl.handle.net/20.500.14352/79875

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Óptica y Optometría

Department

Óptica

Area

Optica

Identifiers

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Now showing 1 - 10 of 27

Multivariate analysis of photonic crystal microcavities with fabrication defects
(Photonic Materials, Devices, and Applications, Pts 1 and 2, 2005) Rico García, José María; López Alonso, José Manuel; Alda Serrano, Javier
Photonic crystal microcavities are defined by the spatial arrangement of materials. In the analysis of their spatial temporal mode distributions Finite-Difference Time-Domain (FDTD) methods have proved its validity. The output of the FDTD can be seen as the realizations of a multidimensional statistic variable. At the same time, fabrication tolerances induce an added and unavoidable variability in the performance of the microcavity. In this contribution we have analyzed the modes of a defective photonic crystal microcavity. The location, size, and shape of the cylinders configuring the microcavity are modelled as having a normal distribution of their parametric descriptors. A principal component analysis is applied to the output of the FDTD for a population of defective microcavities. The relative importance of the defects is evaluated, along with the changes induced in the spatial temporal distribution of electromagnetic field obtained from the calculation.
Characterization of spatial–temporal patterns in dynamic speckle sequences using principal component analysis
(Optical Engineering, 2016) López Alonso, José Manuel; Grumel, Eduardo; Cap, Nelly Lucía; Trivi, Marcelo; Rabal, Héctor; Alda Serrano, Javier
Abstract. Speckle is being used as a characterization tool for the analysis of the dynamics of slow-varying phenomena occurring in biological and industrial samples at the surface or near-surface regions. The retrieved data take the form of a sequence of speckle images. These images contain information about the inner dynamics of the biological or physical process taking place in the sample. Principal component analysis (PCA) is able to split the original data set into a collection of classes. These classes are related to processes showing different dynamics. In addition, statistical descriptors of speckle images are used to retrieve information on the characteristics of the sample. These statistical descriptors can be calculated in almost real time and provide a fast monitoring of the sample. On the other hand, PCA requires a longer computation time, but the results contain more information related to spatial–temporal patterns associated to the process under analysis. This contribution merges both descriptions and uses PCA as a preprocessing tool to obtain a collection of filtered images, where statistical descriptors are evaluated on each of them. The method applies to slow-varying biological and industrial processes.
Maculopatía por puntero láser. ¿Un nuevo problema de salud pública?
(Archivos de la Sociedad Española de Oftalmología, 2016) Alda Serrano, Javier; Gómez Sanz, Fernando Javier; González Martín-Moro, Julio
Project number: 97
Generación de materiales y recursos para la implantación del Plan de Lenguas para la Internacionalización PLI en la Facultad de Óptica y Optometría
(2016) Sánchez Pérez, María Isabel; Alda Serrano, Javier; Carreño Sánchez, Fernando; Cabrero Granado, Eduardo; Peces Peña, María Dolores; Garrido Mercado, Rafaela; Puell Marín, María Cinta; Martín Pérez, Yolanda; López Alonso, José Manuel; Gómez Calderón, Óscar; Melle Hernández, Sonia; Movilla Serrano, Jesús María
Louvers design for LED displays for sunny days
(Displays, 2007) Vázquez Moliní, Daniel; Álvarez Fernández-Balbuena, Antonio; Alda Serrano, Javier; Bernabeu Martínez, Eusebio
The use of louvers attached to variable information display needs to be optimized taking into account different intrinsic and extrinsic parameters. The analysis of the performance of the display–louvers system takes into account the location, orientation, and daily and seasonal variations. The observation of the system is divided depending on the distance of observation. The far distance vision performance use the background luminance. The medium distance performance needs the use of the Contrast Sensitivity Function of the eye.
Seebeck nanoantennas for the detection and characterization of infrared radiation
(Optics Express, 2014) Briones, Edgar; Cuadrado, Alexander; Briones, Joel; Díaz de León, Ramón; Martínez Antón, Juan Carlos; McMurtry, Stefan; Hehn, Michel; Montaigne, François; Alda Serrano, Javier; González, Francisco Javier
Arrays of metallic thermocouples in the shape of spiral nanoantennas are proposed as infrared detectors, which use the thermoelectric properties of the metallic interfaces to generate electrical DC signals. The responsivity of these types of antennas is evaluated from both theoretical and numerical perspectives pointing out its potential as infrared sensors. Moreover, the same structures can be used to characterize the state of polarization of the optical near fields with a spatial resolution comparable to the wavelength.
Application of tomographic techniques to the spatial-response mapping of antenna-coupled detectors in the visible
(Applied Optics, 2008) Rico García, José María; Sánchez Brea, Luis Miguel; Alda Serrano, Javier
A tomographiclike method based on the inverse radon transform is used to retrieve the irradiance map of a focused laser beam. The results obtained from multiple knife-edge measurements have been processed through a kriging technique. This technique allows us to map both the beam irradiance and the uncertainty associated with the measurement method. The results are compared with those achieved in the standard fitting of two orthogonal knife-edge profiles to a modeled beam. The application of the tomographiclike technique does not require any beam model and produces a higher signal-to-noise ratio than the conventional method. As a consequence, the quality of the estimation of the spatial response map of an antenna-coupled detector in the visible is improved.
Angular shifts of paraxial beams by refraction in a plane dielectric/dielectric interface
(Optics Communications, 2002) Alda Serrano, Javier; Rico García, José María
The longitudinal and transverse angular shifts in the refraction of a paraxial beam are calculated by using the plane-wave decomposition of the amplitude of the electric field distribution of the incident beam. The transmission coefficients are expanded into powers of the spatial frequencies. In this paper these spatial frequencies need to be within the paraxial approach around the main direction of propagation of the beam. The beam is characterized by the moments of the square of the modulus of the angular spectrum of the electric field. To compute them, it is necessary to calculate how the spatial frequencies of the beam change along the refraction. The state of polarization of the beam is also included in the analysis. Numerical results are obtained to show the dependence of the angular shifts on the polarization’s state and the symmetry of the beam.
Characterization of FDTD artifacts and modes in photonic crystals
(Proceedings of SPIE, 2004) López Alonso, José Manuel; Rico García, José María; Alda Serrano, Javier
FDTD algorithms are being used as a numeric tool for the analysis of photonic crystals. The definition of the modes associated with them is of interest for the study of the capabilities of photonic crystal devices. The Principal Component Analysis (PCA) has been applied here to a sequence of images corresponding to the electromagnetic fields obtained from the FDTD simulations. PCA has revealed and quantified the importance of the modes appearing in the photonic crystals. The capability of PCA to produce spatial structures, or maps, associated with temporal evolutions has made possible the calculation of the modulus and phase of the modes existing in the photonic crystal. Some other modes, contributing with an almost negligible amount to the total variance of the original data, are also revealed by the method. Besides, PCA has been used to quantify the contribution of the numerical noise of the algorithm and to identify the effect of artifacts related with the matching of the computational grid and the inner geometry of the photonic crystal.
Antenas ópticas y detectores de luz
(Ver y Oír, 2005) Alda Serrano, Javier; López Alonso, José Manuel; Boreman, Glenn; Rico García, José María
La investigación sobre el comportamiento de estructuras metálicas cuyo tamaño es comparable a la longitud de onda de la radiación detectada puede realizarse considerándolas como antenas detectoras de radiación óptica. El diseño, análisis y caracterización de estos dispositivos requiere el estudio de los fenómenos básicos de interacción entre la radiación y la materia. A la vez, su inclusión en sistemas con relevancia tecnológica requiere la medida y caracterización de sus propiedades. Nuestro equipo de investigación, integrado en el «Grupo Complutense de Óptica Aplicada», se ha dedicado durante los últimos años al estudio de estos dispositivos así como a la caracterización de todo tipo de detectores de luz, y a la definición de aquellas figuras de mérito que son relevantes a la hora de establecer su uso.