Quantum well-based tunable antenna-coupled intersubband terahertz (TACIT) detectors at 1.8-2.4 THz

TUnable Antenna-Coupled Intersubband Terahertz (TACIT) detectors use semiconductor quantum well heterostructures to offer tunable detection of light at few-Terahertz frequencies. TACIT detectors have been predicted to have background-limited sensitivity for a 300 K blackbody when operating in either a bolometric or non-bolometric mode. The speed of detection is expected to be 1 ns to less than 10 ps depending on the operating electron temperature and device dimensions. A planar metal antenna couples the incident Terahertz radiation from free space to the quantum well heterostructure. Electrons in the quantum well absorb the radiation, exciting them from the first to the second energy subband. The absorption frequency of the intersubband transition can be tuned by applying a voltage across the device. The quantum well heterostructure is designed so that the subbands have different electron mobilities. Absorption changes the relative number of electrons in each subband, and the effective mobility of the device changes. A current is applied to the active area of the quantum well, and the change in effective mobility is detected as a change in the in-plane resistance of the device. TACIT detectors are being fabricated. Modeling and experimental progress will be discussed.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.