Photodetectors
Mostrando 1-12 de 14 artigos, teses e dissertações.
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1. Prospects for Developing Low-Cost Optical Fiber Sensors for Liquid-Liquid Interface Detection
Abstract This work examines the prospects of a low-cost retroreflection optical sensor system for detection of the interface between two immiscible liquids, for applications in oil separation tanks. The sensor in its simplest configuration comprises a bare fiber optic tip, cleaved at an angle of 90º relative to the longitudinal fiber axis. The device tested
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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2. A study on the physical properties of quantum dot structures for infrared photodetection
Esta tese faz parte de uma proposta mais ampla cujo objetivo global e dominar a tecnologia de fotodetectores de radiacao infravermelha baseados em pontos quanticos semicondutores auto-organizados, os Quantum Dot Infrared Photodetectors (QDIPs), para a faixa de comprimento de onda de 2 a 20 Êm. A tese esta centrada no estudo das propriedades fisicas de ponto
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 12/07/2011
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3. Quantum dots: photodetectors, weak localization and counter-rotating edge states / Pontos-quânticos: fotodetectores, localização-fraca e estados de borda contra-rotativos
In this work we present transport properties of heterostructures with quantum-dots. Three subjects were exploited: on the first one, we observed anomalous quantum Hall plateaus, for wich we attributed to the existence of counter-rotating edge-states; on the second subject, we determined the decoherence time of the bidimensional electron system as a function
Publicado em: 2008
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4. Three-band quantum well infrared photodetector using interband and intersubband transitions.
This thesis presents the modeling, design, fabrication and characterization of a quantum well infrared photodetector (QWIP) capable of detecting near infrared (NIR), mid wavelength infrared (MWIR) and long wavelength infrared (LWIR), simultaneously. The NIR detection was achieved using interband transition while MWIR and LWIR were based on intersubband trans
Publicado em: 2008
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5. Construção e caracterização de fotodetetores metal-semicondutor-metal (MSM). / Construction and characterization of metal-semiconductor-metal (MSM) photodetectors.
The goal of this work was the fabrication of Metal-Semiconductor-Metal (MSM) photodetectors with the following characteristics: dark current of about 1 nA, responsivity of about 0.1 A/W and dark/photocurrent ratio of at least 10. These values ensure that the photodetectors have enough sensitivity to be used in integrated optic sensors. All materials used in
Publicado em: 2006
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6. DEVELOPMENT OF FAR-INFRARED PHOTODETECTORS BASED ON INTRABAND TRANSITIONS IN GAAS/ALGAAS MULTI-QUANTUM WELLS / DESENVOLVIMENTO DE FOTODETECTORES DE INFRAVERMELHO DISTANTE UTILIZANDO TRANSIÇÕES INTRABANDA EM POÇOS QUÂNTICOS MÚLTIPLOS DE GAAS/ALGAAS
Nas Forças Armadas do Brasil existe uma forte demanda pelo desenvolvimento de detectores de infravermelho nacionais para uso em diversas aplicações sujeitas a rígidas restrições de importação, como sistemas de imageamento infravermelho para visão noturna, guiamento de mísseis, sistemas de mira, etc. O objetivo deste trabalho foi desenvolver fotodet
Publicado em: 2006
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7. "Development of the instrumentation and automatic analytical procedures for spectrophotometric determination of surfactants in waters" / "Desenvolvimento de instrumentação e procedimentos analíticos automáticos para a determinação espectrofotométrica de tensoativos em águas"
"In this work, development of the instrumentation and automatic analytical procedures for spectrophotometric determination of surfactants in waters employing the multicommutation concept were proposed. Aiming to system miniaturization, reduction of reagents consumption and effluents generation, solenoids micro-pump and solenoids pinch valves were used for th
Publicado em: 2006
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8. Development of integrated optic receiver in HBT technology / Desenvolvimento de receptor optico integrado em tecnologia HBT
Esta dissertação de mestrado descreve o estudo, projeto e implementação de um receptor optoeletrônico integrado (OEIC) utilizando a tecnologia de transistores bipolares de heterojunção (HBT), fabricados a partir do material semicondutor arseneto de gálio. A grande vantagem deste transistor é o seu alto ganho e baixa resistência de base, o qual poss
Publicado em: 2005
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9. Espectroscopia não-linear de alta resolução em I2, Ti e Ar+
In this work we performed nonlinear high-resolution spectroscopy in I2, Ti and Ar+. Iodine was used as a wavelength reference in the visible. Doppler limited spectra of this molecule were obtained, in particular by using photoacoustic detection. This one proved to be comparable to detection with photodetectors in terms of sensibility and signal-to-noise rati
Publicado em: 1994
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10. Caracterização de fotodetetores para interferometria
Bandwidth and linearity are fundamental parameters in photodetectors behavior, and their knowledge is very important for most experiments in Optics. A new method for frequency response characterization is described in this work. This technique is based on Doppler velocimetry, where the vibration of a commercial loudspeaker in an interferometric setup is used
Publicado em: 1992
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11. A design methodology using signal-to-noise ratio for plastic scintillation detectors design and performance optimization
Purpose: The design of novel plastic scintillation detectors (PSDs) is impeded by the lack of a suitable framework to simulate and predict their performance. The authors propose to use the signal-to-noise ratio (SNR) to model the performance of PSDs that use charge-coupled devices (CCDs) as photodetectors.
American Association of Physicists in Medicine.
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12. Visualization of the spread of electrical activity in rat hippocampal slices by voltage-sensitive optical probes
1. Voltage-sensitive membrane-bound dyes and a matrix of 100 photodetectors were used to detect the spread of evoked electrical activity at the CA1 region of rat hippocampus slices. A display processor was designed in order to visualize the spread of electrical activity in slow motion.