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Real-life applications of terahertz (THz) systems often require fast imaging of large field of view of opaque scenes. Such features have been demonstrated by the development of a complete reflection active THz imaging system that combines QCLs as sources and antenna & cavity coupled micro-bolometer as THz video camera. While better than 5 mm resolution images of 40×60 mm² illuminated surfaces...
This paper describes non-uniformity reduction in terahertz (THz) imaging system, using a coherent THz source and a THz camera. The beam wobbling technique reduces the interference pattern, but illumination distribution often remains. In order to reduce the illumination distribution, post-image process is applied. In this method, the raw image is divided by the reference image without the sample, which...
Large area THz video-rate imaging is demonstrated using a 0.1 Megapixel THz camera having a 17 degree Field of View and 50 Hz frame rate. Active THz see-through imaging has been performed where the THz laser beam has been expanded using a series of custom lenses. Owing to the quality of the beam expansion set-up and good sensitivity of the IRXCAM-THz-384 camera, high quality, large area THz images...
We report on developments of the camera for 590 GHz radiation which has been stitched from four 12×12 antenna-coupled field-effect transistor detector (TeraFET) arrays and supplemented with parallelized low noise read-out electronics. In the current state, the read-out speed of 740 frames-per-second (fps) for a 12×12 element segment has been achieved. It is anticipated that in the final state the...
We present here a smooth walled horn design for the 64 to 128 pixel CHAI the heterodyne camera to be used as one of the first light instruments of the 25m sub-millimeter telescope CCAT. The horn design provides a very high gain that matches the f/6 optics at CCAT Nasmyth foci.
Imaging polarimetry is an important tool for the study of cosmic magnetic fields. In our Galaxy, at submillimeter wavelengths polarization levels up to 10% are measured in the dust emission from molecular clouds and in the synchrotron emission from supernova remnants. We present here results from the commissioning of PolKa, a reflection-type polarimeter working in combination with the Large APEX Bolometer...
This paper reports on the design and performance of a terahertz (THz) linear camera with 50 pW/√Hz noise-equivalent power (NEP). This camera is sensitive to four bands of vertically and horizontally polarized THz radiation (0.22, 0.32, 0.42, and 0.52 THz). The heart of the camera is a diode-based focal plane array (FPA) that has a 10 nV thermal noise level and 1–2 kV/W sensitivity across the four...
Sensitivity of microbolometer Terahertz (THz) focal plane array (FPA) is improved by one order of magnitude at 0.5–0.6 THz, comparing with the previous THz-FPA. This is achieved by modifying an optical cavity structure in a pixel, such that the optical cavity length is extended by a factor of 4–5 than that of the previous structure. Minimum detectable powers (MDPs) per pixel are measured at 4.3, 2...
The 6.5 meter diameter deployable James Webb Space Telescope (JWST) is on track for launch in late 2018, to observe at λ = 0.6 to 28 μm with cameras, spectrometers, and coronagraphs. All instruments have been tested together at their operating temperature with a telescope simulator, all the telescope mirrors are in storage at Goddard waiting for their carbon fiber support structures, and the cryogenic...
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