We report the development and initial results of two Terahertz imaging systems based on monochromatic sources at 0.2 and 2.52 THz. The first is based on a microwave oscillator, whose frequency is multiplied to 0.2 THz, used in conjunction with a zero-bias detector. The sample is scanned across the beam, and transmission images are obtained after processing. The second system allows real-time images, and consists of a methanol gas laser emitting at 119 microns (2.52 THz) and a commercial camera based on a microbolometer array. We describe the construction and performance of the methanol laser and a tunable CO₂ laser, which emits 20 W at the 9P(36) pump line. Due to the high coherence of the laser, this system is particularly suited for diffraction and interference imaging. We have measured the absorption coefficients of a few samples assuming the Beer law.

Date Published: 27 March 2013
PDF: 6 pages
Proc. SPIE 8624, Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications VI, 86240E (27 March 2013); doi: 10.1117/12.2002108

Published in SPIE Proceedings Vol. 8624:
Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications VI
Laurence P. Sadwick; Créidhe M. O'Sullivan, Editor(s)