Silicon carbide diode for increased light output

Transition metals improve the overall light output and the output in particular regions of the electroluminescent of a silicon carbide semiconductor device. These metals /impurities/ introduce levels that can be pumped electrically and affect the efficiency of the recombination process involved in emission of radiation

Light output simulation of LYSO single crystal

We used the Geant4 simulation toolkit to estimate the light collection in a LYSO crystal by using cosmic muons and E=105 MeV electrons. The light output as a function of the crystal length is studied. Significant influence of the crystal wrapping in the reflective paper and optical grease coupling to the photodetectors on the light output is demonstrated.Comment: 9 pages, 5 figure

Impact of long-term stress on the light output of a WRGB AMOLED display

This paper describes how long-term use impacts the light output of a commercial 55' WRGB AMOLED display with InGaZnO TFT backplane. This covers effects which are known by the terms 'aging', 'image-sticking,' and 'burn-in.' The focus is on three different observations: permanent change in light output as a function of time, permanent screen burn-in, and permanent shift in color point. From this work it can be concluded that state-of-the-art OLED displays still suffer from light output instability under prolonged stress. The results suggest that the permanent change in light output can be explained by the combination of three different phenomena: a decrease in efficiency of the OLEDs as a function of time for active subpixels, a positive threshold voltage shift of the driving transistor for active subpixels, and a negative threshold voltage shift of the driving transistor for inactive subpixels, if they are illuminated and/or kept at high temperature. To our knowledge, this is the first work that describes and quantifies the permanent change in light output of a commercial WRGB OLED panel with InGaZnO TFT backplane. It sheds light on which effects occur and can be a valuable tool, both in the design and optimization of OLED panels and in the determining the circumstances under which this technology may be applicable. © 2005-2012 IEEE

A Radiation Damage and Recovery Study for Lead Tungstate Crystals from BTCP and SIC

This paper presents result of a study on radiation damage and recovery for lead tungstate crystals produced at BTCP and SIC. Correlations were observed between initial light output and initial longitudinal transmittance at 360 nm, between the loss of longitudinal transmittance at 440 nm and the loss of light output, and between radiation damages levels at different dose rates. No correlations, however, were found between crystal’s initial optical properties and radiation hardness. Excellent linearity was observed between the variations of crystal’s light output and its longitudinal transmittance at 440 nm in several cycles of irradiation followed by recovery, indicating these PWO crystals can be monitored in situ at LHC

Accurate measurement of a 96% input coupling into a cavity using polarization tomography

Pillar microcavities are excellent light-matter interfaces providing an electromagnetic confinement in small mode volumes with high quality factors. They also allow the efficient injection and extraction of photons, into and from the cavity, with potentially near-unity input and output-coupling efficiencies. Optimizing the input and output coupling is essential, in particular, in the development of solid-state quantum networks where artificial atoms are manipulated with single incoming photons. Here we propose a technique to accurately measure input and output coupling efficiencies using polarization tomography of the light reflected by the cavity. We use the residual birefringence of pillar microcavities to distinguish the light coupled to the cavity from the uncoupled light: the former participates to rotating the polarization of the reflected beam, while the latter decreases the polarization purity. Applying this technique to a micropillar cavity, we measure a $53 \pm2 \%$ output coupling and a $96 \pm 1\%$ input coupling with unprecedented precision.Comment: 6 pages, 3 figure

Doppler shift system

A system is described for measuring velocities of radiating particles based on Doppler shift. Light from the particles is directed through a narrow band optical filter to a Fabry-Perot interferometer initially tuned to a selected center line corresponding to zero particle Doppler shift. The movable mirror of the interferometer is made to sweep about the center line by the output of a modulation oscillator. The fringe pattern output is imaged onto a pin hole through which light is directed to a photomultiplier. The output of the photomultiplier is supplied to a phase sensitive detector with the oscillator output as a reference signal and which operates in the quadrature mode. The detector's output is gain controlled and is combined with the oscillator's output to adjust the interferometer's movable mirror to acquire the line center

Rapid, quantitative determination of bacteria in water

A bioluminescent assay for ATP in water borne bacteria is made by adding nitric acid to a water sample with concentrated bacteria to rupture the bacterial cells. The sample is diluted with sterile, deionized water, then mixed with a luciferase-luciferin mixture and the resulting light output of the bioluminescent reaction is measured and correlated with bacteria present. A standard and a blank also are presented so that the light output can be correlated to bacteria in the sample and system noise can be substracted from the readings. A chemiluminescent assay for iron porphyrins in water borne bacteria is made by adding luminol reagent to a water sample with concentrated bacteria and measuring the resulting light output of the chemiluminescent reaction