Person:
Martínez Antón, Juan Carlos

First Name

Juan Carlos

Last Name

Martínez Antón

URI

https://hdl.handle.net/20.500.14352/79892

Affiliation

Universidad Complutense de Madrid

Faculty / Institute

Óptica y Optometría

Department

Óptica

Area

Optica

Identifiers

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Search Results

Now showing 1 - 10 of 41

Resonant elements contactless coupled to bolometric micro-stripes
(Proceedings of SPIE, 2015) Cuadrado, Alexander; Silva-López, Manuel; López-Alonso, José Manuel; Martínez Antón, Juan Carlos; Ezquerro Rodríguez, José Miguel; González, Francisco Javier; Alda, Javier
One of the main technical difficulties in the fabrication of optical antennas working as light detectors is the proper design and manufacture of auxiliary elements as load lines and signal extraction structures. These elements need to be quite small to reach the location of the antennas and should have a minimal effect on the response of the device. Unfortunately this is not an easy task and signal extraction lines resonate along with the antenna producing a complex signal that usually masks the one given by the antenna. In order to decouple the resonance from the transduction we present in this contribution a parametric analysis of the response of a bolometric stripe that is surrounded by resonant dipoles with different geometries and orientations. We have checked that these elements should provide a signal proportional to the polarization state of the incoming light.
Improvement of driver night vision in foggy environments by structured light projection.
(Heliyon, 2022) Quintana Benito, Jaime; Álvarez Fernández-Balbuena, Antonio; Martínez Antón, Juan Carlos; Vázquez Moliní, Daniel
Nowadays, fog is still a natural phenomenon that hinders our ability to detect targets, particularly in the field of driving where accidents are increasing. In the literature we find different studies determining the range of visibility, improving the quality of an image, determining the characteristics of fog, etc. In this work we propose the possibility of using a structured lighting system, on which we project the light towards the target, limiting the field lighting. We have developed a scattering light propagation model to simulate and subsequently study the veil luminance, generated by backscattering, to predict the decrease in visibility. This simulation considers the type of fog, the relative orientation of various elements (observer, light source and targets). We have built a fog chamber to validate the experimental params of the described system. The results obtained from both the simulation and the experimental measurements demonstrate that it is possible to obtain a high contrast enhancement for viewing a target when illuminated as described. Clearly, this kind of lighting technology will improve the road safety in foggy night environments. The results of this work can also be extrapolated to any situation in which the visibility of an observer is compromised by the environment, such as heavy rain, smoke from fires, among others.
Seebeck nanoantennas for solar energy harvesting
(Applied Physics Letters, 2014) Briones, Edgar; Briones, Joel; Cuadrado, Alexander; Martínez Antón, Juan Carlos; McMurtry, Stefan; Hehn, Michel; Montaigne, François; Alda, Javier; Gonzalez, Francisco Javier
We propose a mid-infrared device based on thermocouple optical antennas for light sensing and energy harvesting applications. We numerically demonstrate that antennas are able to generate low-power dc signals by beneficing of the thermoelectric properties of the metals that constitute them. We theoretically evaluate the optical-to-electrical conversion efficiency for harvesting applications and finally discuss strategies to increase its performance. Thermocouple optical antennas therefore open the route toward the design of photovoltaic devices.
Wavefront measurement by solving the irradiance transport equation for multifocal systems
(Optical Engineering, 2001) Quiroga Mellado, Juan Antonio; Gómez Pedrero, José Antonio; Martínez Antón, Juan Carlos
A method for sensing wavefronts is presented. The method is based on the resolution of the irradiance transport equation, which relates the irradiance distribution and the shape of the wavefront of a light beam propagating along a given direction. The method presents no restrictions in the locations of the measurement planes and incorporates an improved procedure to geometrically correct the acquired images to take into account the effect of ray deflection in the propagation of the irradiance distributions. With the proposed technique, we measure the wavefront at the exit pupil of a progressive addition lens and find good agreement with an alternative deflectometric method.
Perfilómetro tridimensional por absorción óptica en fluídos
(2013) Martínez Antón, Juan Carlos; Universidad Complutense de Madrid
El invento permite medir la topografía de superficies pertenecientes a un substrato (22) transparente o traslúcido que deja pasar luz a su través. Frente a la superficie de estudio (221) se acerca otra de referencia (241) de la que se conoce su topografía. El espacio intermedio se rellena con fluido ópticamente absorbente (23) y se ilumina el conjunto con una fuente extensa (15) de la que se pueden diferenciar al menos dos bandas espectrales con absorción diferente en el fluido (23). El cociente de radiancias integradas en esas bandas espectrales no depende del punto de la fuente ni de la dirección de observación. El registro de imágenes (32) de la luz transmitida en esas bandas espectrales y su análisis posterior permite obtener el perfil completo de la superficie de estudio (221).
Optical characterization of surfaces by robust reflectance determination based on air-gap interference
(Applied Surface Science, 2004) Quiroga Mellado, Juan Antonio; Martínez Antón, Juan Carlos; González Moreno, Ricardo
In this work we present an optical tool for characterizing the reflectance and polarimetric properties of surfaces. It uses only the image of the interference fringe pattern produced in a thin air-gap between the surface of interest and a glass surface acting as a reference. From only the contrast of the fringe pattern captured with a CCD we may obtain the reflectance of the surface, no need of measuring a reference beam. By taking two images with polarized light, we may get then the polarized reflectance R_p and R_s, but also the ellipsometric magnitude Δ, simply as a phase shift between fringes in p and s polarization. A sample of silicon with a thin layer of thermally grown silica is used to test the method.
Seebeck Nanoantennas for Infrared Detection and Energy Harvesting Applications
(2014) Briones, Edgar; Briones, Joel; Martínez Antón, Juan Carlos; Cuadrado, Alexander; McMurtry, Stefan; Hehn, Michel; Montaigne, François; Alda, Javier; Gonzalez, Francisco Javier
Abstract— In this letter we introduce a new type of infrared sensor, based on thermocouple nanoantennas, which enables the energy detection and gathering in the mid-infrared region. The proposed detector combines the Seebeck effect, as a transduction mechanism, with the functionalities of the optical antennas for optical sensing. By using finite-element numerical simulations we evaluate the performance and optical-to-electrical conversion efficiency of the proposed device, unveiling its potential for optical sensing and energy harvesting applications
Variable-spectrum solar simulator
(2012) Martínez Antón, Juan Carlos; Abengoa Solar New Technologies, S.A.
The invention relates to a variable-spectrum solar simulator for characterising photovoltaic systems. The simulator can be used to obtain a spectrum adjusted to the solar spectrum, both for a standard spectrum or a real spectrum adjusted to local irradiation conditions. The simulator also allows the spatial-angular characteristics of the sun to be reproduced. The invention comprises: a broad-spectrum light source, the flux from which is emitted through an aperture; an optical system which collimates the primary source; a system which disperses the beam chromatically; an optical system which forms an image of the dispersed primary source at a given position, at which a spatial mask is placed in order to filter the received irradiance spectrally; an optical system which captures the filtered spectrum and returns, mixes and concentrates same in a secondary source with the desired spectral, angular, and spatial characteristics; an optical system which collimates the secondary source such that it reproduces the angular characteristics of the sun; and a control system.
Improvement of driver night vision in foggy environments by structured light projection
(Heliyon, 2022) Quintana Benito, Jaime; Álvarez Fernández-Balbuena, Antonio; Martínez Antón, Juan Carlos; Vázquez Moliní, Daniel
Nowadays, fog is still a natural phenomenon that hinders our ability to detect targets, particularly in the field of driving where accidents are increasing. In the literature we find different studies determining the range of visibility, improving the quality of an image, determining the characteristics of fog, etc. In this work we propose the possibility of using a structured lighting system, on which we project the light towards the target, limiting the field lighting. We have developed a scattering light propagation model to simulate and subsequently study the veil luminance, generated by backscattering, to predict the decrease in visibility. This simulation considers the type of fog, the relative orientation of various elements (observer, light source and targets). We have built a fog chamber to validate the experimental params of the described system. The results obtained from both the simulation and the experimental measurements demonstrate that it is possible to obtain a high contrast enhancement for viewing a target when illuminated as described. Clearly, this kind of lighting technology will improve the road safety in foggy night environments. The results of this work can also be extrapolated to any situation in which the visibility of an observer is compromised by the environment, such as heavy rain, smoke from fires, among others.
High-Dynamic-Range Spectral Reflectance for the Segmentation of Paint Pigment: Application to Dalí’s Oil Painting Dos Figuras (1926)
(Sensors, 2023) Álvarez Fernandez-Balbuena, Antonio; Gómez Manzanares, Ana; Martínez Antón, Juan Carlos; García Gómez-Tejedor, Jorge; Mayorga Pinilla, Santiago; Durán Roque, Humberto; Vázquez Moliní, Daniel; Álvarez Fernández-Balbuena, Antonio; Martínez Antón, Juan Carlos; Vázquez Molini, Daniel
Restorers and curators in museums sometimes find it difficult to accurately segment areas of paintings that have been contaminated with other pigments or areas that need to be restored, and work on the painting needs to be carried out with minimum possible damage. It is therefore necessary to develop measurement systems and methods that facilitate this task in the least invasive way possible. The aim of this study was to obtain high-dynamic-range (HDR) spectral reflectance and spatial resolution for Dalí’s painting entitled Two Figures (1926) in order to segment a small area of black and white pigment that was affected by the contact transfer of reddish pigment from another painting. Using Hypermatrixcam to measure the HDR spectral reflectance developed by this research team, an HDR multispectral cube of 12 images was obtained for the band 470–690 nm in steps of 20 nm. With the values obtained for the spectral reflectance of the HDR cube, the colour of the area of paint affected by the transfer was studied by calculating the a*b* components with the CIELab system. These a*b* values were then used to define two methods of segmenting the exact areas in which there was a transfer of reddish pigment. The area studied in the painting was originally black, and the contamination with reddish pigment occupied 13.87% to 32% of the total area depending on the selected method. These different solutions can be explained because the lower limit is segmentation based on pure pigment and the upper limit considers red as an exclusion of non-black pigment. Over- and under-segmentation is a common problem described in the literature related to pigment selection. In this application case, as red pigment is not original and should be removed, curators will choose the method that selects the highest red area.