Search results for "electronics"
showing 10 items of 4340 documents
Responsivity measurements of silicon carbide Schottky photodiodes in the UV range
2014
We report on the design and the electro-optical characterization of new classes of 4H-SiC Schottky UV detectors, fabricated employing Ni 2 Si interdigitated strips. We have measured, in dark conditions, the forward and reverse I-V characteristics as a function of temperature and C-V characteristics. Responsivity measurements of the devices, as function of wavelength in the UV range, of package temperature and of applied reverse bias are reported. We also compared devices featuring different strip pitch sizes, discussing their performances, and found the device exhibiting best results.
Electrical connections and driving electronics for piezo-actuated x-ray thin glass optics
2016
Use of thin glass modular optics is a technology currently under study to build light, low cost, large area X-ray telescopes for high energy astrophysics space missions. The angular resolution of such telescopes is limited by local deviations from the ideal shape of the mirrors. One possible strategy to improve it consists in actively correcting the mirror profile by gluing thin ceramic piezo-electric actuators on the back of the glasses. A large number of actuators, however, requires several electrical connections to drive them with the different needed voltages. We have developed a process for depositing conductive paths directly on the back of non-planar thin foil mirrors by means of a p…
Residual strain and stress analysis by speckle interferometry combined with the drill of a groove
2007
A new method for residual stresses determination combining Electronic Speckle Pattern Interferometry (ESPI) with the machining of a groove. The internal stress field is perturbed as the depth of the groove is increased incrementally [1]. The structure finds a new equilibrium state generating displacements which are measured using ESPI. This method was tested on an aluminium alloy plate treated locally by ultrasonic shot-peening. The investigation of the images obtained with the phase shifting technique and fringe patterns makes it possible to analyze, simultaneously, the stress profile along two directions: along the depth of the structure, and along the groove direction.
Note: Simultaneous modulation transfer spectroscopy on transitions of multiple atomic species for compact laser frequency reference modules
2018
We present a technique for simultaneous laser frequency stabilization on transitions of multiple atomic species with a single optical setup. The method is based on modulation transfer spectroscopy, and the signals are separated by modulating at different frequencies and electronically filtered. As a proof of concept, we demonstrate simultaneous spectroscopy of the potassium D1, D2 and rubidium D2 transitions. The technique can be extended in principle to other atomic species given the availability of optics and cells and allows the development of versatile and compact frequency reference modules.
A continuous wave 10 W cryogenic fiber amplifier at 1015 nm and frequency quadrupling to 254 nm
2013
A stable, continuous wave, single frequency fiber amplifier system at 1015 nm with 10W output power is presented. It is based on a large mode double clad fiber cooled to liquid nitrogen temperature. The amplified light is frequency quadrupled to 254 nm and used for spectroscopy of the 6^1S - 6^3P transition in mercury.
<title>Properties of ITO transparent electrode thin films on different substrates</title>
2003
Indium tin oxide (ITO) is optically transparent semiconductor that finds extensive applications in liquid crystal displays, photovoltaic cells, touch screen displays, electrochromic smart windows and more. As with all such electrode materials, there is a compromise between conductivity and optical properties. Different substrate materials and underlying layers are playing important role in transparency (better contrast and less absorption, increased brightness), surface morphology (smoothness, homogeneously) and conductivity of the ITO films. We compared optical, electrical and morphology properties of ITO films onto polymer substrate, obtained from company "SIDRABE Inc." (Latvia) and ITO f…
Wavelength multiplexed hydrogen sensor based on palladium-coated fibre-taper and Bragg grating
2004
A novel configuration of a wavelength multiplexed hydrogen sensor based on a palladium-coated tapered fibre and a fibre Bragg grating is presented. This scheme allows cascading several sensors along a single fibre, which increases the capability of implementing multipoint sensor networks for volumetric detection. Moreover, in this configuration the light interacts twice with the palladium layer, thus enhancing the sensitivity of the sensor.
Light-emitting fabrics
2015
Light-emitting fibres that suit integration with textiles are prepared by dip-coating a steel wire with an electroluminescent material and then cleverly wrapping the structure with a carbon nanotube sheet that functions as a transparent electrode.
On the potential of 914 nm pumping of Nd:YVO4 for laser operation at 1064 nm
2011
1064 nm-Nd :YVO4 lasers were pumped at 808 nm and 914 nm. The comparative study shows that 914 nm-pumping is adapted for cw operation whereas 808 nm-pumping provides higher population inversion interesting for Q-switched operation.
InAlN underlayer for near ultraviolet InGaN based light emitting diodes
2019
We report on InAlN underlayer (UL) to improve the efficiency of near ultraviolet (NUV) light emitting diodes (LEDs). While InGaN UL is commonly used in high-efficiency blue LEDs it may absorb light for shorter wavelengths. InAlN lattice-matched to GaN exhibits a bandgap of 4.6 eV. This allows alleviating absorption issues in NUV LEDs. We demonstrate that the internal quantum efficiency of 405 nm single InGaN/GaN quantum well LEDs with InAlN UL is similar to 70% compared to less than 10% for LEDs without UL. Excellent I-V characteristics are achieved thanks to polarization charge screening with high doping level at the InAlN/GaN interface. (C) 2019 The Japan Society of Applied Physics