We describe the construction and performance of a passive, real-time terahertz camera based on a modular, 64-element linear array of cryogenic hotspot microbolometers. A reflective conical scanner sweeps out a 2 m ×4 m(vertical × horizontal) field of view (FOV) at a standoff range of 8 m. The focal plane array is cooled to 4 K in a closed cycle refrigerator, and the signals are detected on free-standing bridges of superconducting Nb or NbN at the feeds of broadband planar spiral antennas. The NETD of the focal-plane array, referred to the target plane and to a frame rate of 5 s−1, is 1:25 K near the center of the array and 2 K overall.
Citation: Applied Optics
Pub Type: Journals
terahertz, millimeter-wave, camera, imaging, superconducting, focal-plane array