Applied Physics

Speedier Screening

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Science  28 Nov 2003:
Vol. 302, Issue 5650, pp. 1480
DOI: 10.1126/science.302.5650.1480d

The generation and detection of terahertz radiation (or T-rays), which lies in the frequency range between short radio waves (100 GHz) and the far infrared (10 THz), is a technology presently being developed for large-area imaging, with a view toward security, because of its non-ionizing energy and ability to penetrate objects such as material packaging and clothing. However, the techniques that provide sufficient output power for large-scale imaging are constrained to operate at cryogenic operation, to emit only monochromatic radiation, or are untunable—all of which limit somewhat their general application.

Baker et al. present a broadband T-ray imaging system in which the radiation is generated during the interaction between femtosecond pulses from a 1.06-μm laser and the photoconductive semiconductor InGaAs. Coupling the optical pump pulses with the generated T-rays allows them to employ phase-sensitive detection techniques, thereby raising the possibility of real-time imaging of biological and non-biological samples alike. — ISO

Appl. Phys. Lett. 83, 4113 (2003).

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