TWO-COLOR DETECTORS FOR SPACE-BASED INTERCEPTORS

THE RECENT ADVANCES IN BANDGAP ENGINEERING BY MOLECULAR BEAM EPITAXY (MBE) HAVE PRODUCED A STRAINED SUPERLATTICE (SSL) OF INSB/INASSB CAPABLE OF BEING MADE INTO PHOTODIODES TAILORABLE TO ANY SPECTRAL REPONSE WITHIN THE INFRARED SPECTRUM (1-16 MICRON). TO EXPLOIT THESE ADVANCES, THIS PROPOSAL IS MADE TO DEVELOP A MULTILAYERED STRUCTURE OF INSB/INASSB THAT WILL RESPONSE TO TWO SPECTRAL BANDS SEPARATELY BUT SIMULTANEOUSLY. THIS INNOVATIVE DETECTOR, SO-CALLED TWO-COLOR DETECTOR, WILL FILL A NEED IN STRATEGIC DEFENSE SYSTEMS, SUCH AS SPACE-BASED INTERCEPTOR, TO PERFORM DISCRIMINATION OF TARGET AGAINST CLUTTER, PLUME AGAINST BOOSTER BODY, TARGET AGAINST DECOY AND RE-ENTRY VEHICLE (RV) AGAINST CLUTTER. THIS NEED CANNOT BE EASILY SATISFIED BY CONVENTIONAL DETECTOR TECHNOLOGY. THIS EFFORT IS TO DEVELOP A MULTILAYERED STRUCTURE OF INSB/INASSB THAT WILL RESPOND TO TWO SEPARATE SPECTRAL BANDS SIMULTANEOUSLY. THIS STRUCTURE CONSISTS OF TWO SEPARATE DETECTORS, CONFIGURED INTIMATELY ONE ATOP THE OTHER. ONE DETECTOR WILL RESPOND TO THE MEDIUM WAVELENGTH INFRARED (MWIR, 3-5 MICRON) BAND AND ANOTHER TO THE LONG WAVELENGTH INFRARED (LWIR, 8-16 MICRON) BAND. THE RESEARCH WILL USE THE MBE TECHNIQUE TO FORM A NEAR-PERFECT LATTICE MATCHING BETWEEN THE MULTILAYERS AND TO PERFORM IN-SITU DOPING FOR FABRICATING THE PHOTOVOLTAIC JUNCTIONS FOR THE DETECTORS. SPECIAL EFFUSION SOURCES, EPITAXIAL PROCESSES AND DEMONSTRATION OF EPITAXY WILL BE DESIGNED, DELINEATED AND MADE, RESPECTIVELY, IN PHASE I TOWARD THE DEVELOPMENT OF THE TWO-COLOR DETECTOR. PHASE II WILL BE DEVOTED TO OPTIMIZING THE TWO-COLOR DETECTOR, AND PHASE III WILL EXTEND THIS TECHNOLOGY TO DEMONSTRATE A PROTOTYPE ARRAY OF THE TWO-COLOR DETECTORS. ?????????