We present results of 2D real-time imaging of terahertz (THz) beam generated by a photoconductive antenna driven by a femtosecond oscillator. The detector, operating at room temperature, is a 320 x 240 array of antenna-coupled microbolometers with integrated CMOS read-out electronics delivering 25 images per second. High quality images of broadband THz beams covering the 0.1-2 THz range are recorded while maintaining a signal-to-noise ratio of 10 for detected THz power as low as 25 nW. The compactness of the easy-to-use uncooled camera makes it very useful for the alignment of systems such as THz time-domain spectrometers and for the characterization of emitters, optics and other components.

This paper addresses the problem of critical operations in Degraded Visual Environment (DVE). DVE usually refer when the perception of a pilot is degraded by environmental factors, including the presence of obscurants from bad weather (e.g. fog, rain, snow) or accidental events (e.g. brownout, whiteout, smoke). Critical operations in DVE are a growing field of research as it is a cause of numerous fatal accidents for operational forces. Due to the lack of efficient sources and sensors in the Terahertz (THz) region, this domain has remained an unexplored part of the electromagnetic spectrum. Recently, the potential use of sub-Terahertz waves has been proposed to see through dense clouds of obscurants (e.g. sand, smoke) in DVE conditions. In order to conduct a performance evaluation of sub-Terahertz systems, several sub-terahertz systems (e.g. bolometer-array cameras, liquid helium cooled bolometers) were operated in artificial controlled DVE conditions at ONERA facilities. The purpose of this paper is to report field experiments results in controlled DVE conditions: attenuation measurements from 400 GHz to 700 GHz with a performance evaluation of different sub-Terahertz systems are presented.

An n=-1 flat lens based on photonic crystal semiconductor technology is evaluated for infrared detection purposes. The idea consists in exploiting the backscattered waves of an incident plane wave impinging on a target placed in the focal region of a flat lens. It is shown that subwavelength detection of micronic dielectric targets can be obtained at 1.55 μm using the double focus of reflected waves induced by negative refraction. Complex relations among the intrinsic nature, the shape and size of the target, and detection efficiency are interpreted in terms of target eigenmode excitation. Reflectivity is modulated by the intrinsic mode nature, transverse, circular, or longitudinal, with an enhancement of the detection sensitivity in the case of whispering-gallery modes. It is believed that such a study paves the way to the definition of original noninvasive infrared sensors.

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