Raytheon is developing NIR sensor chip assemblies (SCAs) for scanning and staring 3D LADAR systems. High
sensitivity is obtained by integrating high performance detectors with gain, i.e., APDs with very low noise Readout
Integrated Circuits (ROICs). Unique aspects of these designs include: independent acquisition (non-gated) of pulse
returns, multiple pulse returns with both time and intensity reported to enable full 3D reconstruction of the image.
Recent breakthrough in device design has resulted in HgCdTe APDs operating at 300K with essentially no excess noise
to gains in excess of 100, low NEP <1nW and GHz bandwidths and have demonstrated linear mode photon counting.
SCAs utilizing these high performance APDs have been integrated and demonstrated excellent spatial and range
resolution enabling detailed 3D imagery both at short range and long ranges. In the following we will review progress in
real-time 3D LADAR imaging receiver products in three areas: (1) scanning 256 × 4 configuration for the Multi-Mode
Sensor Seeker (MMSS) program and (2) staring 256 × 256 configuration for the Autonomous Landing and Hazard
Avoidance Technology (ALHAT) lunar landing mission and (3) Photon-Counting SCAs which have demonstrated a
dramatic reduction in dark count rate due to improved design, operation and processing.
Linear mode photon counting (LMPC) provides significant advantages in comparison with Geiger Mode (GM) Photon
Counting including absence of after-pulsing, nanosecond pulse to pulse temporal resolution and robust operation in the
present of high density obscurants or variable reflectivity objects. For this reason Raytheon has developed and
previously reported on unique linear mode photon counting components and modules based on combining advanced
APDs and advanced high gain circuits. By using HgCdTe APDs we enable Poisson number preserving photon counting.
A metric of photon counting technology is dark count rate and detection probability. In this paper we report on a
performance breakthrough resulting from improvement in design, process and readout operation enabling >10x
reduction in dark counts rate to ~10,000 cps and >104x reduction in surface dark current enabling long 10 ms
integration times. Our analysis of key dark current contributors suggest that substantial further reduction in DCR to
~ 1/sec or less can be achieved by optimizing wavelength, operating voltage and temperature.
Raytheon Vision Systems (RVS) has developed a family of high performance large format infrared detector arrays
whose detectors are most effective for the detection of long and very long wavelength infrared energy. This paper
describes the state of the art in mega-pixel Si:As Impurity Band Conduction (IBC) arrays and relevant system
applications that offers unique off-the-shelf solutions to the astronomy community. Raytheon's Aquarius-1k, developed
in collaboration with ESO, is a 1024 × 1024 pixel high performance array with a 30μm pitch that features high quantum
efficiency IBC detectors, low noise, low dark current, and on-chip clocking for ease of operation. This large format array
was designed for ground-based astronomy applications but lends itself for space based platforms too. The detector has
excellent sensitivity out to 27μm wavelength. The readout circuit has several programmable features such as low gain for
a well capacity of 11 × 106e-, high gain for a well capacity of 106e- and a programmable number of outputs (16 or 64).
Programmable integration time and integration modes, like snapshot, rolling and non-destructive integrations, allow the
Aquarius to be used for a wide variety of applications and performance. A very fast full frame rate of 120Hz is achieved
with 64 outputs (32 outputs per side) and a programmable centered windowing will accommodate a wide range of
readout rates. The multiplexer and packaging design utilizes two alignment edges on the SCA which can be butted on
two sides for expansion to 2k × 1k and wider focal planes. Data is shown on several focal plane arrays to demonstrate
that very low noise and high quantum efficiency performance has been achieved. This array leverages over thirty years
of experience in both ground and space based astronomy sensor applications. The technology has been successfully
demonstrated on programs such as NASA's Spitzer Space Telescope and Japan's Akari Space Telescope, and will be
used on the Mid-Infrared Instrument (MIRI) aboard the James Webb Space Telescope (JWST).
Raytheon Vision Systems (RVS) in collaboration with HRL Laboratories is contributing to the maturation and manufacturing readiness of third-generation two-color HgCdTe infrared staring focal plane arrays (FPAs). This paper will highlight data from the routine growth and fabrication of 256x256 30μm unit-cell staring FPAs that provide dual-color detection in the mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) spectral regions. FPAs configured for MWIR/MWIR, MWIR/LWIR and LWIR/LWIR detection are used for target identification, signature recognition and clutter rejection in a wide variety of space and ground-based applications. Optimized triple-layer-heterojunction (TLHJ) device designs and molecular beam epitaxy (MBE) growth using in-situ controls has contributed to individual bands in all two-color FPA configurations exhibiting high operability (>99%) and both performance and FPA functionality comparable to state-of-the-art single-color technology. The measured spectral cross talk from out-of-band radiation for either band is also typically less than 10%. An FPA architecture based on a single mesa, single indium bump, and sequential mode operation leverages current single-color processes in production while also providing compatibility with existing second-generation technologies.