4 May 2007 Towards an active real-time THz camera: first realization of a hybrid system
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We report the realization of a hybrid system for stand-off THz reflectrometry measurements. The design combines the best of two worlds: the high radiation power of sub-THz micro-electronic emitters and the high sensitivity of coherent opto-electronic detection. Our system is based on a commercially available multiplied Gunn source with a cw output power of 0.6 mW at 0.65 THz. We combine it with electro-optic mixing with femtosecond light pulses in a ZnTe crystal. This scheme can be described as heterodyne detection with a Ti:sapphire fs-laser acting as local oscillator and therefore allows for phase-sensitive measurements. Example images of test objects are obtained with mechanical scanning optics and with measurement times per pixel as short as 10 ms. The test objects are placed at a distance of 1 m from the detector and also from the source. The results indicate diffraction-limited resolution. Different contrast mechanisms, based on absorption, scattering, and difference in optical thickness are employed. Our evaluation shows that it should be possible to realize a real-time multi-pixel detector with several hundreds of pixels and a dynamic range of at least two orders of magnitude in power.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
T. May, T. May, C. am Weg, C. am Weg, A. Alcin, A. Alcin, B. Hils, B. Hils, T. Löffler, T. Löffler, H. G. Roskos, H. G. Roskos, } "Towards an active real-time THz camera: first realization of a hybrid system", Proc. SPIE 6549, Terahertz for Military and Security Applications V, 654907 (4 May 2007); doi: 10.1117/12.719197; https://doi.org/10.1117/12.719197


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