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