Components, concepts, and technologies for useful video rate THz imaging

The recent arrival of TeraHertz large format focal plane arrays has opened the door for numerous applications not previously available for this exciting technology. Video-rate imaging is now a reality and little or no scanning is required. INO has a proven microbolometer based focal plane array that shows good sensitivity over a large THz bandwidth and videos have been successfully acquired of objects hidden behind barrier materials. While these videos successfully proved the real-time capabilities of the INO imager, the quality of the images required substantial system level improvement to be useful for detection and identification purposes in various applications. To this end, INO has designed and fabricated optical components for its active imaging set-up that allows for superior quality real-time images. This paper discusses the concepts and techniques used to create these components. A comparison of images taken using the same THz camera with and without these innovative techniques is presented. In addition, as stand-off detection and imaging is the ultimate objective, an analysis of the atmospheric attenuation over the THz wavelength region is also discussed.