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We report results from characterizing the HgCdTe avalanche photodiode (APD) arrays developed for lidar at infrared wavelengths by using the high density vertically integrated photodiodes (HDVIP) technique. The results show >90% quantum efficiencies between 0.8 μm and the cut-off wavelength, >600 APD gain, near unity excess noise factor, 6-10 MHz electrical bandwidth and <0.5 fW/Hz noise equivalent power (NEP). The detectors provide linear analog output with a dynamic range of 2-3 orders of magnitude at a fixed APD gain without averaging, and over 5 orders of magnitude by adjusting the APD gain settings. They have been used successfully in airborne CO and CH integrated path differential absorption (IPDA) lidar as precursors for use in space lidar.
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http://dx.doi.org/10.1364/OE.25.016589 | DOI Listing |
HgCdTe avalanche photodiodes (APDs) exhibit unique gain stability, making them advantageous for weak signal detection. However, research on neutral impurities (NIs) scattering in HgCdTe remains limited, and the non-parabolic electron dynamics pose significant error in current device scale models. These limitations hinder the theoretical and the industrial development of HgCdTe APD.
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October 2024
Planetary Geology, Geophysics and Geochemistry Laboratory, Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
Photodetectors play a critical role in space lidars designed for scientific investigations from orbit around planetary bodies. The detectors must be highly sensitive due to the long range of measurements and tight constraints on the size, weight, and power of the instrument. The detectors must also be space radiation tolerant over multi-year mission lifetimes with no significant performance degradation.
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January 2022
Institute of Applied Physics, Military University of Technology, 2 Kaliskiego St., 00-908 Warsaw, Poland.
The trend related to reach the high operating temperature condition (HOT, temperature, > 190 K) achieved by thermoelectric (TE) coolers has been observed in infrared (IR) technology recently. That is directly related to the attempts to reduce the IR detector size, weight, and power dissipation (SWaP) conditions. The room temperature avalanche photodiodes technology is well developed in short IR range (SWIR) while devices operating in mid-wavelength (MWIR) and long-wavelength (LWIR) require cooling to suppress dark current due to the low energy bandgap.
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May 2021
The avalanche is the foundation of the understanding and vast applications of the breakdown of semiconductors and insulators. Present numerical theories analyzing the avalanche photodetectors are mainly split into two categories: the macroscopic empirical model with fitting parameters and the microscopic process simulation with statistical estimations. Here, we present a parameter-free analytic theory of the avalanche for a narrow-band material, HgCdTe, originated from quantum mechanics, avoiding any fitting parameter or any statistical estimation while taking advantage of both categories.
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April 2021
Leonardo DRS Electro-Optical Infrared Systems, Dallas, TX 75243, USA.
We report the development of a new type of space lidar specifically designed for missions to small planetary bodies for both topographic mapping and support of sample collection or landing. The instrument is designed to have a wide dynamic range with several operation modes for different mission phases. The laser transmitter consists of a fiber laser that is intensity modulated with a return-to-zero pseudo-noise (RZPN) code.
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