title: Passive terahertz camera for standoff security screening.
abstract: 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 x 4 m (vertical x 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.
authors.affiliation: Optoelectronics Division, National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA. erich.grossman@nist.gov
authors.forename: Erich
authors.initials: E
authors.lastname: Grossman
authors.forename: Charles
authors.initials: C
authors.lastname: Dietlein
authors.forename: Juha
authors.initials: J
authors.lastname: Ala-Laurinaho
authors.forename: Mikko
authors.initials: M
authors.lastname: Leivo
authors.forename: Leif
authors.initials: L
authors.lastname: Gronberg
authors.forename: Markus
authors.initials: M
authors.lastname: Gronholm
authors.forename: Petteri
authors.initials: P
authors.lastname: Lappalainen
authors.forename: Anssi
authors.initials: A
authors.lastname: Rautiainen
authors.forename: Aleksi
authors.initials: A
authors.lastname: Tamminen
authors.forename: Arttu
authors.initials: A
authors.lastname: Luukanen