Recursos de colección

Archivo Digital UPM (109.492 recursos)

This is an institutional repository providing access to the research output of the institution. Primarily contains thesis.

Materia = Optica

Mostrando recursos 1 - 20 de 238

  1. Feasibility of tracking laparoscopic instruments in a box trainer using a Leap Motion Controller

    Oropesa García, Ignacio; Jong, Tom de; Sanchez Gonzalez, Patricia; Dankelman, J.; Gómez Aguilera, Enrique J.
    Motion analysis is employed to assess minimally invasive surgical psychomotor skills in box trainers. Tracking of laparoscopic instruments requires sensor-based systems that can be expensive, limit movements and modify their ergonomic properties. We evaluate the feasibility of using Leap Motion as a cheap, unobtrusive alternative. Four experiments were performed to determine its precision while tracking a laparoscopic instrument inside and outside a box trainer. Static long and short term precision of the Leap Motion was <2.5 mm. Precision between 12 different positions within the box trainer was <0.7 mm for all measured distances between neighbors. Dynamic precision when moving the...

  2. Accelerated life test of high luminosity blue LEDs

    Nogueira Díaz, Eduardo; Orlando, Vincenzo; Ochoa Serna, Javier; Fernandez, A.; Vazquez Lopez, Manuel
    A complete Accelerated Life Test on high luminosity blue LEDs is presented. The test was conducted at different temperatures, humidity and current conditions, involving a total of seven individual tests. Life models were obtained for the catastrophic failures of the tests and then a complete temperature, humidity and current model was developed,which enabled the calculation of the life of the LEDs for any of these conditions. Catastrophic failures and model parameters were consistent with earlier results using different high luminosity LEDs. Non-catastrophic failures were modelled with their corresponding luminous power loss on each test, with expected results.

  3. Increasing the quantum efficiency of InAs/GaAs QD arrays for solar cells grown by MOVPE without using strain-balance technology

    Kalyuzhnyy, Nikolay A.; Mintairov, Sergey A.; Salii, Roman A.; Nadtochiy, Alexey M.; Payusov, Alexey S.; Brunkov, Pavel M.; Nevedomsky, Vladimir N.; Shvarts, Maxim Z.; Martí Vega, Antonio; Andreev, Viacheslav M.; Luque López, Antonio
    Research into the formation of InAs quantum dots (QDs) in GaAs using the metalorganic vapor phase epitaxy technique ispresented. This technique is deemed to be cheaper than the more often used and studied molecular beam epitaxy. The bestconditions for obtaining a high photoluminescence response, indicating a good material quality, have been found among awide range of possibilities. Solar cells with an excellent quantum ef?ciency have been obtained, with a sub-bandgapphoto-response of 0.07 mA/cm2per QD layer, the highest achieved so far with the InAs/GaAs system, proving the potentialof this technology to be able to increase the ef?ciency of lattice-matched multi-junction solar...

  4. The optical properties of CuPbSbS3-bournonite with photovoltaic applications

    Tablero Crespo, César
    CuPbSbS3-bournonite is a quaternary semiconductor derived from the Cuâ?Sbâ?S semiconductors with numerous possibilities including optoelectronic and photovoltaic applications. An analysis focusing on the potential for solar cells is carried out starting from first-principles density functional theory with orbital-dependent one-electron potentials. In order to understand the fundamental factors responsible for the absorption, the absorption coefficients have been split into inter- and intra-species contributions. The absorption coefficients are used as a criterion for evaluating the efficiencies when this material is used to absorb sunlight at several concentrations. The results indicate their applicability in photovoltaic devices as absorbent of the solar spectrum with...

  5. Desarrollo de un sistema robotizado para la composición automática de imágenes mono e hiperespectrales para reflectografía de infrarrojos

    García Ayala, Enrique
    El presente Proyecto Fin de Carrera realiza el desarrollo de una aplicación informática llamada VARIM 2.0 capaz de controlar unos sistemas robotizados de adquisición de imágenes, en banda ancha e hiperespectrales, en el infrarrojo. Dicha aplicación es capaz de obtener, mediante uniones manuales o automáticas de las imágenes adquiridas, una composición del mosaico reflectográfico. También es capaz de obtener, de imágenes hiperespectrales adquiridas, unas imágenes en distintas longitudes de onda o hiperespectrales, para obtener información precisa de las distintas capas que forman una obra de arte. Además, dispone de herramientas para el tratamiento digital de imágenes.

  6. Optically enhanced photon recycling in mechanically stacked multijunction solar cells

    Steiner, Myles A.; Geisz, John F.; Ward, J. Scott; García Vara, Iván; Friedman, Daniel J.; King, Richard R.; Chiu, Philip T.; France, Ryan M.; Duda, Anna; Olavarria, Waldo J.; Young, Michelle; Kurtz, Sarah R.
    Multijunction solar cells can be fabricated by mechanically bonding together component cells that are grown separately. Here, we present four-junction four-terminal mechanical stacks composed of GaInP/GaAs tandems grown on GaAs substrates and GaInAsP/GaInAs tandems grown on InP substrates. The component cells were bonded together with a low-index transparent epoxy that acts as an angularly selective reflector to the GaAs bandedge luminescence, while simultaneously transmitting nearly all of the subbandgap light. As determined by electroluminescence measurements and optical modeling, the GaAs subcell demonstrates a higher internal radiative limit and, thus, higher subcell voltage, compared with GaAs subcells without the epoxy reflector....

  7. Selective monostability in multi-stable systems

    Sevilla Escoboza, Ricardo; Pisarchik, Alexander N.; Jaimes-Reátegui, Rider; Huerta Cuellar, Guillermo
    We propose a robust method that allows a periodic or a chaotic multi-stable system to be transformed to a monostable system at an orbit with dominant frequency of any of the coexisting attractors. Our approach implies the selection of a particular attractor by periodic external modulation with frequency close to the dominant frequency in the power spectrum of a desired orbit and simultaneous annihilation of all other coexisting states by positive feedback, both applied to one of the system parameters. The method does not require any preliminary knowledge of the system dynamics and the phase space structure. The efficiency of...

  8. "METHOD": a tool for mechanical, electrical, thermal, and optical characterization of single lens module design

    Besson, Pierre; Domínguez Domínguez, César; Voarino, Philippe; García-Linares Fontes, Pablo; Weick, Clement; Lemiti, Mustapha; Baudrit, Mathieu
    The optical characterization and electrical performance evaluation are essential in the design and optimization of a concentrator photovoltaic system. The geometry, materials, and size of concentrator optics are diverse and different environmental conditions impact their performance. CEA has developed a new concentrator photovoltaic system characterization bench, METHOD, which enables multi-physics optimization studies. The lens and cell temperatures are controlled independently with the METHOD to study their isolated effects on the electrical and optical performance of the system. These influences can be studied in terms of their effect on optical efficiency, focal distance, spectral sensitivity, electrical efficiency, or cell current matching....

  9. Márgenes de eficiencia de la biestabilidad óptica activa en semiconductores

    Solís Ros, Javier; González Marcos, Ana; Martín Pereda, José Antonio
    La importancia de la biestabilidad óptica activa es un hecho conocido, pero el uso de este efecto no lineal requiere de una correcta caracterización del dispositivo, que nos permita determinar las condiciones de polarización del mismo, para una función dada, entre las diversas aplicaciones que ofrece. El presente trabajo describe la metodología empleada para la caracterización de un diodo láser mediante herramientas CAD comerciales. Se presentan los resultados de los parámetros más característicos, contraste y anchura de histéresis, en las condiciones estándar para poder identificar los márgenes de eficiencia.

  10. Simulación de la propagación mediante óptica de rayos en fibras ópticas

    Rincón Cabezas, Óscar
    El proyecto tiene como objetivo estudiar las técnicas de óptica geométrica para analizar el trazado de los frentes de onda de las señales que se propagan por fibras ópticas de Salto de Índice e Índice Gradual. Para ello se ha estudiado la teoría de la denominada técnica de análisis eikonal basada en óptica geométrica. Se ha pretendido hacer un estudio de los distintos tratamientos para estudiar la propagación de los rayos luminosos, empezando por las propiedades que se conocen desde la base que se trabaja como si las ondas fueran en fase, creando el frente de ondas. Así el estudio está...

  11. On the analytical demonstration of Planck-Einstein relation

    Molina Morales, Eddy Luis
    In this paper a possible analytical demonstration of Planck's Law for the spectral distribution of the electromagnetic energy radiated by hot bodies is presented, but in this case, the solutions of Maxwell's equations for the electromagnetic radiation problem of Hertz’s dipole are used. The concepts of quantum energy and of photon are redefined from the classical point of view, relating them to the possible electronic nature of electromagnetic waves and the electromagnetic field in general. Both the physical analysis and the concepts proposed respect the law of conservation of energy and allow to finally express the quantic constant, which is...

  12. On the analytical demonstration of Planck-Einstein relation

    Molina Morales, Eddy Luis
    In this paper a possible analytical demonstration of Planck's Law for the spectral distribution of the electromagnetic energy radiated by hot bodies is presented, but in this case, the solutions of Maxwell's equations for the electromagnetic radiation problem of Hertz’s dipole are used. The concepts of quantum energy and of photon are redefined from the classical point of view, relating them to the possible electronic nature of electromagnetic waves and the electromagnetic field in general. Both the physical analysis and the concepts proposed respect the law of conservation of energy and allow to finally express the quantic constant, which is...

  13. Analysis of a random modulation single photon counting differential absortion lidar system for space-borne CO2 sensing

    Ai, Xiao; Pérez Serrano, Antonio; Quatrevalet, Mathieu; Nock, Richard W.; Dahnoun, Naim; Ehret, Gerhard; Esquivias Moscardo, Ignacio; Rarity, John G.
    The ability to observe the Earth's carbon cycles from space provides scientists an important tool to analyze climate change. Current proposed systems are mainly based on pulsed integrated path differential absorption lidar, in which two high energy pulses at different wavelengths interrogate the atmosphere sequentially for its transmission properties and are back-scattered by the ground. In this work an alternative approach based on random modulation single photon counting is proposed and analyzed; this system can take advantage of a less power demanding semiconductor laser in intensity modulated continuous wave operation, benefiting from a better efficiency, reliability and radiation hardness. Our...

  14. Optical processing, Power response of a modulated general optical system

    Muriel Fernández, Miguel Ángel; Capmany Francoy, José
    Optical processing: Power response of a modulated general optical system

  15. Real-time optical spectrum analyzer

    Muriel Fernández, Miguel Ángel; Martín Pereda, José Antonio
    Real-time optical spectrum analyzer

  16. Dispositivo optoelectrónico biestable para sistemas de fibra óptica

    Beltran Torreira, Rafael; Muriel Fernández, Miguel Ángel
    Dispositivo optoelectrónico biestable para sistemas de fibra óptica

  17. Conmutador 2 x 2 unidireccional para sistemas por fibras ópticas

    Beltran Torreira, Rafael; Muriel Fernández, Miguel Ángel
    Conmutador 2 x 2 unidireccional para sistemas por fibras ópticas

  18. Procesamiento de señales mediante guiaonda óptica monomodo

    Muriel Fernández, Miguel Ángel
    Procesamiento de señales mediante guiaonda óptica monomodo

  19. Procesado Cuántico de la Información : Apuntes

    Muriel Fernández, Miguel Ángel; Rodríguez Fortuño, Francisco José
    Estos apuntes de Procesado Cuántico de la Información, escritos por Francisco José Rodríguez Fortuño, están basados en las clases y el material aportado por el Prof. Miguel Angel Muriel Fernández.

  20. 1D and 2D neutral particle patterning by dielectrophoretic forces on z-cut Fe:LiNbO3 crystals

    Muñoz Martínez, Juan Francisco; Elvira, Iris; Burgos, Hector; Jubera, Mariano; García Cabañes, Angel; Ramiro Diaz, Jose Bruno; Alcazar De Velasco Rico, Angel Manuel; Carrascosa, Mercedes
    1D and 2D patterning of uncharged micro- and nanoparticles via dielectrophoretic forces on photovoltaic z-cut Fe:LiNbO3 have been investigated for the first time. The technique has been successfully applied with dielectric micro-particles of CaCO3 (diameter d = 1-3 μm) and metal nanoparticles of Al (d = 70 nm). At difference with previous experiments in x- and y-cut, the obtained patterns locally reproduce the light distribution with high fidelity. A simple model is provided to analyse the trapping process. The results show the remarkably good capabilities of this geometry for high quality 2D light-induced dielectrophoretic patterning overcoming the important limitations presented by previous...

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