We report the first demonstration of: 1) wide-wavelength range, infrared transparent conductors (ITCs) made of silver nanowires (Ag NWs), and 2) ITC contact-integrated prototype, InAsSb midwavelength IR (MWIR) detectors. The Ag NW-based ITCs show optical transmittance (Tλ) of ,,94% in the 0.9-2.5 μm wavelength range with a sheet resistance (Rs) of 19.1 Ω/□. Tλ of the Ag NW-ITC decreases slowly with increasing wavelength, resulting in Tλ ,,92%-87% at 2.5- 8 μm (MWIR) and Tλ ,,87%-82% at 8-15 μm (LWIR). The Ag NWbased ITC makes good ohmic contacts on InAsSb-based MWIR detectors with contact resistance of <;0.5 Ω · mm. The ITC contact-integrated prototype InAsSb IR detectors are front-side illuminated and show external quantum efficiency (QE) of >85% at 4.25 μm and 150K. The measured external QE remains at the same high level regardless of detector fill factor. These results indicate that Ag NW-ITCs may enable future pixel scaling for front-side illuminated, high-density-format focal plane arrays without compromising QE, responsivity, and detector performance.

Advanced LADAR receivers enable high accuracy identification of targets at ranges beyond standard EOIR sensors. Increased sensitivity of these receivers will enable reductions in laser power, hence more affordable, smaller sensors as well as much longer range of detection. Raytheon has made a recent breakthrough in LADAR architecture by combining very low noise similar to 30 electron front end amplifiers with moderate gain >60 Avalanche Photodiodes. The combination of these enables detection of laser pulse returns containing as few as one photon up to 1000s of photons. Because a lower APD gain is utilized the sensor operation differs dramatically from traditional "Geiger mode APD" LADARs. Linear mode photon counting LADAR offers advantages including: determination of intensity as well as time of arrival, nanosecond recovery times and discrimination between radiation events and signals. In our talk we will present an update of this development work: the basic amplifier and APD component performance, the front end architecture, the demonstration of single photon detection using a simple 4 x 4 SCA and the design and evaluation of critical components of a fully integrated 8x8 linear mode photon counting camera under development in support of the Ultra-Sensitive Detector (USD) program sponsored by AFRL-Kirtland.