Title :
Terahertz laser based standoff imaging system
Author :
Linden, Kurt J. ; Neal, William R. ; Waldman, Jerry ; Gatesman, Andrew J. ; Danylov, Andriy
Author_Institution :
Spire Corp., Bedford, MA
Abstract :
Definition and design of a terahertz standoff imaging system has been theoretically investigated. Utilizing terahertz quantum cascade lasers for transmitter and local oscillator, a detailed analysis of the expected performance of an active standoff imaging system based on coherent heterodyne detection has been carried out. Five atmospheric windows between 0.3 THz and 4.0 THz have been identified and quantified by carrying out laboratory measurements of atmospheric transmission as a function of relative humidity. Using the approximate center frequency of each of these windows, detailed calculations of expected system performance vs target distance, pixel resolution, and relative humidity were carried out. It is shown that with 1.5 THz laser radiation, a 10m standoff distance, 1 m times 1 m target area, and a 1cm times 1cm pixel resolution, a viable imaging system should be achievable. Performance calculations for various target distances, target pixel resolution, and laser frequency are presented
Keywords :
heterodyne detection; humidity; measurement by laser beam; quantum cascade lasers; submillimetre wave imaging; submillimetre wave lasers; 0.3 to 4.0 THz; 10 m; heterodyne detection; local oscillator; pixel resolution; relative humidity; target distance; terahertz quantum cascade lasers; terahertz standoff imaging system; Frequency; Humidity; Image analysis; Laboratories; Laser theory; Local oscillators; Optical imaging; Performance analysis; Quantum cascade lasers; Transmitters;
Conference_Titel :
Applied Imagery and Pattern Recognition Workshop, 2005. Proceedings. 34th
Conference_Location :
Washington, DC
Print_ISBN :
0-7695-2479-6
DOI :
10.1109/AIPR.2005.42
