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Abstract-We show experimentally that a high-resolution imaging radar operating at 576-605 GHz is capable of detecting weapons concealed by clothing at standoff ranges of 4-25 m. We also demonstrate the critical advantage of 3-D image reconstruction for visualizing hidden objects using active-illumination coherent terahertz imaging. The present system can image a torso with 1 cm resolution at 4 m standoff in about five minutes. Greater standoff distances and much higher frame rates should be achievable by capitalizing on the bandwidth, output power, and compactness of solid state Schottky-diode based terahertz mixers and multiplied sources.

We present a process for fabricating a field-effect transistor based on vertically standing InAs nanowires and demonstrate initial device characteristics. The wires are grown by chemical beam epitaxy at lithographically defined locations. Wrap gates are formed around the base of the wires through a number of deposition and etch steps. The fabrication is based on standard III–V processing and includes no random elements or single nanowire manipulation.