Quasi-optical sytems

Quasi-optics is a generic term that refers to using a combination of waveguide and optical techniques to construct high performance instruments and systems, usually in the mm-wave and sub-mm-wave regimes. Quasi-optical techniques are commonly used in multi-band radiometers, large telescopes, high frequency electron magnetic resonance instruments, some radar systems, and for materials characterisation. The Group has been designing and manufacturing quasi-optical systems and associated components, such as feedhorns, polarisers, isolators/circulators, filters, lenses and mirrors, for nearly 40 years, and collaborates closely with Thomas Keating Ltd. for their manufacture and commercialisation. In general, for most passive waveguide components there is a quasi-optical counterpart that offers higher performance, although often in a less compact form. Many wideband quasi-optical system will feature frequency-independent optics, feedhorns with constant phase centres, and are configured to reduce the small aberrations produced by off-axis mirrors. Systems are often constructed on an optical breadboard.

Wideband quasi-optical systems are often designed with frequency independent optics
where it is important for the feedhorn to maintain a constant phase centre, preferably at the horn aperture.