Readout Techniques for Drift and Low Frequency Noise Rejection in Infrared Arrays     

Gert Finger  Reinhold J. Dorn  Alan W. Hoffman  Hamid Mehrgan  Manfred Meyer  Alan F. M. Moorwood  Joerg Stegmeier 《Experimental Astronomy》2002,14(2):117-127

Three different methods are presented to subtract thermal drifts and low-frequency noise from the signal of infrared array. The first is dead pixels with open Indium bumps, the second is reference output as implemented on the Hawaii2 multiplexer, and the third is dark pixels to emulate reference cells having a capacity connected to the gate of the unit cell field-effect transistor (FET). The third method is the most effective and yields a reduction in readout noise from15.4–9.4 erms. A novel method will be described to extend this readout technique to the Aladdin 1 K × 1 K InSb array. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

CMOS Detector Technology     

Alan Hoffman  Markus Loose  Vyshnavi Suntharalingam 《Experimental Astronomy》2005,19(1-3):111-134

An entry level overview of state-of-the-art CMOS detector technology is presented. Operating principles and system architecture are explained in comparison to the well-established CCD technology, followed by a discussion of important benefits of modern CMOS-based detector arrays. A number of unique CMOS features including different shutter modes and scanning concepts are described. In addition, sub-field stitching is presented as a technique for producing very large imagers. After a brief introduction to the concept of monolithic CMOS sensors, hybrid detectors technology is introduced. A comparison of noise reduction methods for CMOS hybrids is presented. The final sections review CMOS fabrication processes for monolithic and vertically integrated image sensors.  相似文献   

Conversion Gain and Interpixel Capacitance of Cmos Hybrid Focal Plane Arrays     

Gert Finger  James W. Beletic  Reinhold Dorn  Manfred Meyer  Leander Mehrgan  Alan F. M. Moorwood  Joerg Stegmeier 《Experimental Astronomy》2005,19(1-3):135-147

The conversion gain of optical and infrared focal plane CMOS hybrid arrays is a fundamental parameter, whose value computes into the derivation of other parameters characterizing the performance of a detector. The widespread “noise squared versus signal” method used to obtain the conversion gain can overestimate the nodal capacitance of the detector pixel by more than 20% for infrared arrays and by more than 100% for Si-PIN diode arrays. This is because this method does not take account of the capacitive coupling between neighboring pixels. A simple technique has been developed to measure the nodal capacitance directly by comparing the voltage change of an external calibrated capacitor with the voltage change on the nodal capacitor of the detector pixel. The method is elaborated in detail and has been verified with a Si-PIN diode array hybridized to a Hawaii-2RG multiplexer using an Fe ⁵⁵ X-ray source. It is also in good agreement with a stochastic method based on 2D autocorrelation.  相似文献   

Influence of annealing conditions on impurity species in arsenic-doped HgCdTe grown by molecular beam epitaxy     

越方禹  陈璐  李亚巍  胡志高  孙琳  杨平雄  褚君浩 《海洋学报(英文版)》2010,29(11)

Based on our previous work, the influence of annealing conditions on impurity species in in-situ arsenic (As)-doped Hg_1-xCd_xTe (x≈ 0.3) grown by molecular beam epitaxy has been systematically investigated by modulated photoluminescence spectra. The results show that (i) the doped-As acting as undesirable shallow/deep levels in as-grown can be optimized under proper annealing conditions and the physical mechanism of the disadvantage of high activation temperature, commonly assumed to be more favourable for As activation, has been discussed as compared with the reports in the As-implanted HgCdTe epilayers (x≈ 0.39), (ii) the density of V_textrmHg has an evident effect on the determination of bandgap (or composition) of epilayers and the excessive introduction of V_Hg will lead to a short-wavelength shift of epilayers, and (iii) the V_textrmHg prefers forming the V_Hg-As_Hg complex when the inactivated-As (As_Hg or related) coexists in a certain density, which makes it difficult to annihilate V_Hg in As-doped epilayers. As a result, the bandedge electronic structures of epilayers under different conditions have been drawn as a brief guideline for preparing extrinsic p-type epilayers or related devices.  相似文献   

Scientific detector workshop 2022 on-sky performance verification of near-infrared e−APD technology for wavefront sensing and demonstration of e−APD pixel performance to improve the sensitivity of large science focal planes     

Gert Finger  Frank Eisenhauer  Reinhard Genzel  Christopher Mandla  Ian Baker  Domingo Alvarez  Antonio Amorim  Wolfgang Brandner  Christophe Dupuy  Casey Deen  Derek Ives  Leander Mehrgan  Manfred Meyer  Karin Perraut  Guy Perrin  Jörg Stegmeier  Christian Straubmeier  Harald J. Weller  Vincent Isgar 《Astronomische Nachrichten》2023,344(8-9):e20230069

Near-infrared adaptive optics as well as fringe tracking for coherent beam combination in optical interferometry require the development of high-speed sensors. Because of the high speed, a large analog bandwidth is required. The short exposure times result in small signal levels which require noiseless detection. Both requirements cannot be met by state-of-the-art conventional CMOS technology of near-infrared arrays as has been attempted previously. A total of five near-infrared SAPHIRA 320 × 256 pixel HgCdTe e⁻APD arrays have been deployed in the wavefront sensors and in the fringe tracker of the VLTI instrument GRAVITY. The current limiting magnitude for coherent exposures with GRAVITY is m_k = 19, which is made possible with ADP technology. New avalanche photo-diode array (APD) developments since GRAVITY include the extension of the spectral sensitivity to the wavelength range from 0.8 to 2.5 μm. After GRAVITY a larger format array with 512 × 512 pixels has been developed for both AO applications at the ELT and for long integration times. Since dark currents of <10⁻³ e⁻/s have been demonstrated with 1Kx1K e⁻APD arrays and 2Kx2K e⁻APD arrays have already been developed, the possibilities and adaptations of e⁻APD technology to provide noiseless large-format science-grade arrays for long integration times are also discussed.  相似文献