Optical Readout Technique Research Articles

Optical Readout in Pinpi'n and Pini'p Imagers: A Comparison

AbstractOptimized a-SiC:H multilayer devices based on two different tandem configurations (TCO/pinpi'n/TCO and TCO/pini'p/TCO) are compared and tested for proper image recognition and color separation process using an optical readout technique. In both configurations the doped layers are based on a-SiC:H to increase image resolution and to prevent image blurring. To profit from the light filtering properties of the active absorbers, the intrinsic layer of the front diode (i layer) is based on a-SiC:H and the back one (i'layer) on a-Si:H.The effect of the applied voltage on the color selectivity is discussed. Results show that the relative spectral response curves demonstrate rather good separation between the red, green and blue basic colors. Combining the information obtained under positive and negative applied bias a colour image is acquired, using the same optical technique either in pinpi'n or in the pini'p configuration, without colour filters or pixel architecture.

Real-time profile of microcantilevers for sensing applications

An optical readout technique has been developed for real-time monitoring of the profile of microcantilever arrays for sensing applications. The technique is based on the automated two-dimensional scanning of a laser beam by using voice-coil actuators. Cantilever profiles are obtained with subnanometer resolution and a processing speed of about ten cantilevers per second. The technique is applied for real-time monitoring of the adsorption of the alkylthiol mercaptohexanol in an aqueous environment by using an array of five microcantilevers. Molecular adsorption produces a cantilever strain that significantly differs from the Stoney’s model. Main strain changes are strongly located near the cantilever clamping.

IR imaging using uncooled microcantilever detectors

Uncooled bimaterial microcantilever detectors were fabricated and used to obtain infrared (IR) images of objects at temperatures ranging from room temperature to a few hundred °C. Images were obtained using both single 50 μm×50 μm microcantilever IR detectors and arrays of microcantilever detectors. Thermal radiation from the target object was imaged onto the detector and the resulting temperature change caused microcantilever bending due to the bimaterial effect. This micromechanical bending was measured using two different non-contact optical readout techniques and IR images were obtained. A smaller size (20 μm×20 μm) microcantilever IR detector was also used to capture IR images of near room temperature objects.

An optical method for three-dimensional dosimetry

Accurate determination of the spatial distribution of the absorbed dose ofionising radiation plays an important role in radiotherapy, industrialradiation processing and many other applications. Computer calculations havefrequently been used to estimate three-dimensional (3D) dose distributions incomplex geometries and it becomes important to validate these by accurate 3Dmeasurements. For this purpose we have been investigating the use of gelatingels loaded with a modified Fricke solution which are pale orange inappearance and which, upon irradiation, become increasingly purple when viewedin normal light. This ferrous sulphate xylenol orange in gelatin gel (FXG)system displays very good properties, such as sensitivity, linearity anddynamic range, that make it suitable for 3D dosimetry applications. Ahigh-speed optical tomography readout technique has been developed enablingtwo-dimensional projections of optical absorption data to be recorded rapidly.From these data the 3D absorbed dose distribution can quicklybe derived with minimal degradation due to ion diffusion.

6th SRP International Symposium. Achievements & Challenges: Advancing Radiation Protection into the 21st Century, Southport, 14-18 June 1999

6th SRP International Symposium. Achievements & Challenges: Advancing Radiation Protection into the 21st Century, Southport, 14-18 June 1999

Infrared vision using uncooled micro-optomechanical camera

This letter presents the design, fabrication, and imaging results of an uncooled infrared (IR) camera that contains a focal plane array of bimaterial microcantilever sensors, and an optical readout technique that measures cantilever deflections in the nanometer range to directly project a visible image of the IR scene on the human eye or a visible camera. The results suggest that objects at temperatures as low as 100 °C can be imaged with the best noise-equivalent temperature difference (NEΔT) in the range of 10 K. It is estimated that further improvements that are currently being pursued can improve NEΔT to about 50 mK.

Performance of the PHENIX EM Calorimeter

The PHENIX Electromagnetic Calorimeter is a large 15,552 channel lead/scintillator sampling calorimeter based on the shish-kebab optical readout technique. In this report we summarize studies leading to an optimal design for measurement of photons and electrons in the 1 GeV momentum range within the high multiplicity environment expected for events at RHIC. Timing resolutions of /spl sim/100 ps and a sampling dominated energy resolution of 8% at 1 GeV are featured. We also present a novel scheme for monitoring gain and timing of our entire system. Test results with a 144 channel preproduction "super-module" exposed to electron and hadron beams at the AGS are described. The calorimeter is currently under construction in Russia and the US and will be fully installed at RHIC during 1998.

Photo-induced and electrooptic properties of (Pb,La)(Zr,Ti)O3 films for optical memories

Abstract Photo-induced hysteresis changes and electrooptic effects in sol-gel Pb(Zr,Ti)O3 (PZT) and (Pb,La)(Zr,Ti)O3 (PLZT) films have been studied in an effort to evaluate these materials for optical memory applications. The films exhibit two distinct, but related, types of photo-induced changes in their hysteresis behavior: 1) a photo-induced change in the coercive voltage and 2) a photo-induced suppression of the switchable polarization. Both types of photo-induced hysteresis changes are due to trapping of photo-generated charge carriers at sites which minimize internal depolarizing fields. The photo-induced changes are reproducible and stable and are, thus, suitable for optical memory applications. In addition, polarization-dependent changes in the refractive indices can be the basis of a nondestructive optical readout technique. To characterize these electrooptic effects, a waveguide refractometry technique has been used to independently determine field-induced changes in the ordinary and extraordina...

Characteristics Of The Linear Array Total Internal Reflection (TIR) Electrooptic Spatial Light Modulator For Optical Information Processing

A first-order analytical model which describes the imaging performance of the total internal reflection (TIR) linear array spatial light modulator is presented. Two modulator configurations are identified, each with a distinct imaging response. The modulator crystal orientation defines which image response model applies. Several optical readout techniques for converting the optical phase modulation into an intensity modulation are described.