Surface plasmon enhanced tunneling diode detection of THz radiation

This Small Business Technology Transfer Research phase I program will develop a new class of uncooled THz detectors for the 1-10THz band with a novel design using surface plasmon resonant cavities with integrated metal-insulator-metal tunneling diodes as the detecting element. Tunneling diodes provide ultrafast broadband response, potentially into the visible (300THz), but demonstrated performance using antenna coupled diodes has been disappointing for a variety of reasons. The proposed approach solves all of the problems limiting antenna coupled detectors. In particular, the design allows for large, tunable collection area to optimize the tradeoff between signal/noise ratio and image resolution, high efficiency power coupling into the tunneling diode detector, and wavelength scaling through geometric parameters with a single detector technology. This program will examine the fundamental mechanisms involved through closely coupled finite element modeling, nanofabrication of test structures operating at 28THz, and detailed optical characterization. Detailed designs for the 1-10THz band will be developed through modeling. BENEFIT: THz imaging has great potential for applications ranging from biological imaging, security screening, and material characterization. The lack of highly sensitive, low power, low cost detectors that can be fabricated into arrays has prevented the introduction of commercial imagers. This program will develop uncooled detector elements for advanced THz focal plane array imagers, greatly expanding the commercial market.