Search results for "Optoelectronics"

Dynamical binary modulation of ultrabroadband light beams by using principal states of polarization of liquid crystal devices

2009

Dynamical modulation of ultrabroadband beams, such as those produced by femtosecond laser or incoherent sources, is not an easy task due to the dispersive nature of the devices commonly employed. Phase modulation has been performed by means of deformable micromirror arrays. These devices are expensive and do not permit amplitude modulation. For micro- and nano-structuring of materials with femtosecond lasers is common to pattern the surface with the light irradiance produced by a computer generated hologram implemented onto a liquid crystal (LC) type spatial light modulator. This enables dynamical patterning [1,2]. Reduced spectral bandwidths, of the order of tens of nanometers, have been u…

Optoelectronic Information Encryption with Incoherent Light

2005

Potential application of some wide band gap materials for UV dosimetry

2005

Properties of some wide band gap materials–natural and CVD diamonds – have been studied for their potential application in UV dosimetry, using methods of optically stimulated luminescence and thermoluminescence. The observed properties are compared with those of the previously studied AlN ceramics. From the OSL excitation spectra, it follows that spectral sensitivity of the studied materials falls mainly into the UVC range, OSL and TL emission spectra are located within the visible light region, thus suitable for usual photodetectors. OSL stimulation spectra of the studied materials have a continuous character and are located in a broad visible/near infrared spectral region implying that th…

Influence of neutron and gamma-ray irradiations on rad-hard optical fiber

2015

We investigated point defects induced in rad-hard Fluorine-doped optical fibers using both a mixed source of neutrons (fluences from 1015 to 1017 n/cm2) and γ-rays (doses from 0.02 to 2 MGy) and by a γ-ray source (dose up to 10 MGy). By combining several complementary spectroscopic techniques such as radiation-induced attenuation, confocal micro-luminescence, time-resolved photo-luminescence and electron paramagnetic resonance, we evidenced intrinsic and hydrogen-related defects. The comparison between the two irradiation sources highlights close similarities among the spectroscopic properties of the induced defects and the linear correlation of their concentration up to 1016 n/cm2. These r…

Measurement technique for real-time and low-cost biosensing using photonic bandgap structures

2011

We present a sensing technique based on using photonic bandgap structures where only the output power is monitored, without the need of tunable sources or spectrum analyzers, thus providing a real-time and low-cost system.

<title>High-frequency electrodeless light sources for application</title>

2001

The high-frequency electrodes light sources (HFELS) are widely used as bright radiators of narrow and intensive spectral lines covering spectral region from VUV to IR. In this work we shall give a short overview of our experience in preparation of HFELS, containing He, H, Rb, Hg, Zn, Pb, As, Sb, Bi, Tl, Hg-Cd, Hg-Zn, Hg-Cd-Zn, Se-Te for different applications. Special attention would be paid for HFELS use in Zeeman mercury analyzer, in Atomic absorption analyzer and Angle and glass refractive index measurement system.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

PV effect of fullerene/poly(3-hexylthiophene) blend sensitized by phthalocyanine having infrared absorption CT band

2008

An attempt was made to extend the photosensitivity spectral range of fullerene/poly(3-hexylthiophene) blend to NIR region by adding extra electron donor — hydroxygallium phthalocyanine (GaOHPc) with a strong and wide intermolecular charge transfer (CT) band around 830 nm. Multilayer cells of ITO/PEDOT: PSS/6 GaOHPc/P3HT: C61(CO2Et)2 have been prepared by spin coating with vacuum evaporated Al or In top electrodes. Significant photosensitivity of the cells was in 370–900 nm spectral range. However charge carrier photogeneration efficiency was 3 times higher for illumination in P3HT absorption band as compared with the GaOHPc CT band at 830 nm. But when GaOHPc was mixed in the blend forming P…

Spin-crossover nanoparticles anchored on MoS2 layers for heterostructures with tunable strain driven by thermal or light-induced spin switching

2021

In the past few years, the effect of strain on the optical and electronic properties of MoS2 layers has attracted particular attention as it can improve the performance of optoelectronic and spintronic devices. Although several approaches have been explored, strain is typically externally applied on the two-dimensional material. In this work, we describe the preparation of a reversible ‘self-strainable’ system in which the strain is generated at the molecular level by one component of a MoS2-based composite material. Spin-crossover nanoparticles were covalently grafted onto functionalized layers of semiconducting MoS2 to form a hybrid heterostructure. Their ability to switch between two spi…

Ferroelectric liquid crystalline polysiloxanes with high spontaneous polarization and possible applications in nonlinear optics

1990

Analysis of Transition Metal Oxides based Heterojunction Solar Cells with S-shaped J-V curves

2020

The use of transition metal oxides for the selective carrier contact in the crystalline silicon solar cells technology is rising to interest for the excellent optoelectrical properties of these materials whose implementation, however, can result in lousy performing cells due to an S-shaped electrical characteristic. In this paper, we fabricated solar cells showing S-shaped J-V curve and carried out an analysis of the reasons of such behavior using a model involving the series of a standard cell equivalent circuit with a Schottky junction in order to explain these atypical performances. A good matching between the experimental measurements and the adopted theoretical model was obtained. The …