School of Physics & Astronomy

Millimetre wave and related devices

Quasi-optics at mm-wave frequenciesThe millimetre wave group specialises in developing instruments for applications involving electromagnetic radiation of wavelength 1 to 4mm (frequency 70-300 GHz). These wavelengths lie between the visible and microwaves, and have only recently started to become exploited. The group has developed new sources, detectors, and quasi-optical components for a range of systems used for remote sensing, radar and signal processing. Our pictures show the use of plastic lenses and wire-grid polarisers in this technology. At these wavelengths, any hot object radiates significantly and this has been exploited for imaging and for systems for protection from friendly-fire in battlefield situations.

Another project using mm-waves is attempting to create an early-warning system for volcanic eruptions, illustrated in action below.

mm-wave radar being used to map surface features at Montserrat

The use of these high frequencies is also allowing spectacular advances in electron-spin-resonance spectroscopy. In these techniques the mm-waves interact with electrons in a sample to allow probing of samples of biological, chemical and physical interest. Work is also in progress on microwave-triggered switches and electron sources.

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BDS 27.7.05