| 摘要 |
A tunable antenna-coupled intersubband terahertz (TACIT) detector is based on intersubband absorption in doped semiconductor quantum wells. THz-frequency radiation impinges on a coplanar antenna. The antenna couples radiation into a narrow constriction in a two dimensional electron gas (the "active region") with electric field perpendicular to the plane of the antenna. Radiation, which is at the intersubband absorption frequency, is absorbed in the active region. The resulting change in resistance through the constriction is detected. The frequency of the absorption, and hence the detection frequency, can be tuned over the 1-5 THz range by applying small voltages between a front and back gate. The efficiency with which radiation couples from the antenna into the active region can be optimized at each frequency. TACIT detectors solve a number of outstanding problems associated with Terahertz detection including: 1. Voltage tunability eliminates the need for bulky spectrometers and interferometers in certain applications. 2. Superior combination of speed and sensitivity. 3. Relaxed cooling requirements.
|
