A dedicated automatic target recognition and tracking optical correlator (OC) system using advanced processing technology has been developed. Rapidly cycling data-cubes with size, shape, and orientation are employed with software algorithms to isolate correlation peaks and enable tracking of targets in maritime environments with future track prediction. The method has been found superior to employing maximum average correlation height filters for which the correlation peak intensity drops off in proportion to the number of training images. The physical dimensions of the OC system may be reduced to as small as 2 in. × 2 in. × 3 in. (51 mm × 51 mm × 76 mm) by modifying and minimizing the OC components.
Remote sensing and characterization of high temperature targets on the Earth's surface is required for many cross-disciplinary science investigations and applications including fire and volcano impacts on ecology, the carbon cycle, and atmospheric composition. For decades this research has been hindered by insufficient spatial resolution and/or detector saturation of satellite sensors operating at short and mid-infrared wavelengths (1-5μm) where the spectral radiance from high temperature (>800 K) surfaces is most significant. To address this critical need, the Jet Propulsion Laboratory and partnering institutions are developing a compact modular high dynamic range (HDR) multispectral imager concept, with the flexibility to operate in the short, mid-or long-wavelength infrared spectral bands.
SiGe offers a low-cost alternative to conventional infrared sensor material systems such as InGaAs, InSb, and HgCdTe for developing near-infrared (NIR) photodetector devices that do not require cooling and can operate with relatively low dark current. As a result of the significant difference in thermal expansion coefficients between germanium (Ge) and silicon (Si), tensile strain incorporated into SiGe detector devices through specialized growth processes can extend their NIR wavelength range of operation. We have utilized high throughput, large-area complementary metal-oxide semiconductor (CMOS) technology to fabricate Ge based p-in (PIN) detector devices on 300 mm Si wafers. The two-step device fabrication process, designed to effectively reduce the density of defects and dislocations arising during deposition that form recombination centers which can result in higher dark current, involves low temperature epitaxial deposition of Ge to form a thin p + seed layer, followed by higher temperature deposition of a thicker Ge intrinsic layer. Phosphorus was then ion-implanted to create devices with n + regions of various doping concentrations. Secondary ion mass spectroscopy (SIMS) has been utilized to determine the doping profiles and material compositions of the layers. In addition, electrical characterization of the I-V photoresponse of different devices from the same wafer with various n + region doping concentrations has demonstrated low dark current levels (down to below 1 nA at −1 V bias) and comparatively high photocurrent at reverse biases, with optimal response for doping concentration of 5 × 10 19 cm −3. C. Rouse et al.
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