A substrate-free optical readout focal plane array with a heat sink structure

A substrate-ffee optical readout focal plane array （FPA） operating in 8-12 um with a heat sink structure （HSS） was fabricated and its performance was tested. The temperature distribution of the FPA with an HSS investigated by using a commercial FLIR IR camera shows excellent uniformity. The thermal cross-talk effect existing in traditional substrate-free FPAs was eliminated effectively. The heat sink is fabricated successfully by electroplating copper, which provides high thermal capacity and high thermal conductivity, on the frame of substrate-free FPA. The FPA was tested in the optical-readout system, the results show that the response and NETD are 13.6 grey/K （F / # = 0.8） and 588 inK, respectively.

Polarization readout analysis for multilevel phase change recording by crystallization degree modulation

Four different states of Si15Sb85 and Ge2Sb2Te5 phase change memory thin films are obtained by crystallization degree modulation through laser initialization at different powers or annealing at different temperatures. The polarization characteristics of these two four-level phase change recording media are analyzed systematically. A simple and effective readout scheme is then proposed, and the readout signal is numerically simulated. The results show that a high-contrast polarization readout can be obtained in an extensive wavelength range for the four-level phase change recording media using common phase change materials. This study will help in-depth understanding of the physical mechanisms and provide technical approaches to multilevel phase change recording.

A microscale optical implant for continuous in vivo monitoring of intraocular pressure

Intraocular pressure(IOP)is a key clinical parameter in glaucoma management.However,despite the potential utility of daily measurements of IOP in the context of disease management,the necessary tools are currently lacking,and IOP is typically measured only a few times a year.Here we report on a microscale implantable sensor that could provide convenient,accurate,ondemand IOP monitoring in the home environment.When excited by broadband near-infrared(NIR)light from a tungsten bulb,the sensor’s optical cavity reflects a pressure-dependent resonance signature that can be converted to IOP.NIR light is minimally absorbed by tissue and is not perceived visually.The sensor’s nanodot-enhanced cavity allows for a 3–5 cm readout distance with an average accuracy of 0.29 mm Hg over the range of 0–40 mm Hg.Sensors were mounted onto intraocular lenses or silicone haptics and secured inside the anterior chamber in New Zealand white rabbits.Implanted sensors provided continuous in vivo tracking of short-term transient IOP elevations and provided continuous measurements of IOP for up to 4.5 months.

Simulation of thermal processes in metamaterial millimeter-wave to infrared converter for millimeter-wave imager

The main characteristics of millimeter-wave(MM-wave)image detector were simulated by means of accurate numerical modeling of thermophysical processes in a metamaterial MM-to-IR converter.The converter represents a multilayer structure consisting of an ultra thin resonant metamaterial absorber and a perfect emissive layer.The absorber consists of a dielectric self-supporting film that is metallized from both sides.A micropattern is fabricated from one side.Resonant absorption of the MM waves induces the converter heating that yields enhancement of IR emission from the emissive layer.IR emission is detected by IR camera.In this contribution an accurate numerical model for simulation of the thermal processes in the converter structure was created by using COMSOL Multiphysics software.The simulation results are in a good agreement with experimental results that validates the model.The simulation shows that the real-time operation is provided for the converter thickness less than 3µm and time response can be improved by decreasing of the converter thickness.The energy conversion efficiency of MM waves into IR radiation is over 80%.The converter temperature increase is a linear function of a MM-wave radiation power within three orders of the dynamic range.The blooming effect and ways of its reducing are also discussed.The model allows us to choose the ways of converter structure optimization and improvement of image detector parameters.

Studies of an X-ray imaging detector based on THGEM and CCD camera

Introduction The photons generated by the electron avalanche in gaseous detectors are known as the secondary scintillation light,of which the spectrum range is from ultraviolet to visible.So it is possible to collect directly the avalanche-induced photons in visible range by light sensors,such as charged-couple device(CCD).The optical readout is a new method for 2-D imaging of high spatial resolution based on the micro-pattern gaseous detectors(MPGDs).Purpose The traditional charge readout method for the MPGDs is complicated,expensive,and strongly depends on the technology of application-specific integrated circuit.In some cases,for example,low-frame-rate 2-D imaging,the optical readout has more advantages,such as simple,cheap and easy to use.Therefore,a gaseous detector was developed based on the thick gaseous electron multiplier(THGEM)and the ordinary scientific CCD camera as readout to realize the X-ray imaging instead of charge readout.Methods and materials The THGEMs with 60×60 mm^(2) sensitive area were developed to reach high gain,and the Ar+CF4 gas mixture was chosen for strong light emission.And so a general scientific CCD can be used for readout and replacing the intensified CCD,which is more expensive than general CCD.Results Some clear X-ray images were obtained by this optical readout THGEM detector,and the spatial resolution achieved is 275µm.It is indicated that this kind of detectors have promising imaging capability and great potential for practical application.

Development and application of a modular test system for the HV-CMOS pixel sensor R&D of the ATLAS HL-LHC upgrade

Background High-voltage CMOS is a promising technology for the pixel sensor of tracking detectors in the collider experiments.Extensive studies are being carried out by theATLASCollaboration to investigate the possibility of using theHV-CMOS technology in the HL-LHC upgrade of the ATLAS inner tracker detector.Purpose The CaRIBOu(Control and Readout Itk BOards)is a modular test system developed to test the HV-CMOS pixel sensor prototypes and demonstrators.Methods This test system consists of pixel sensor specific front-end chip boards,a control and readout board(CaR board),a central interface board and the back-end DAQ system.Currently,two DAQ solutions are available for the CaRIBOu system,one is based on the FELIX(front-end link eXchange)readout system and the other is based on the Gigabit Ethernet link.Results Various testbeam experiments have been carried out with the CaRIBOu system since 2015 for the pixel sensors fabricated by the AMS HV-CMOS 180 nm and 350 nm technologies.Conclusion The test results show that this test system is very flexible and could be adapted to the test of different pixel sensors with minimum effort,and the performance meets the testbeam requirements.