Waveguide systems and devices are used over a very wide frequency rage. However, at frequencies on the order of 100GHz and higher, single mode guides can become very lossy, so an alternative method is required for signal propagation. One option is quasi optics which uses optical elements just as conventional optics does, including lenses, polarisers and mirrors. Unlike conventional optics, however, the optical element size is the same order of magnitude as the wavelength, so Gaussian beam mode theory is required.

At St Andrews, we make many of our optical elements including polariser grids, lenses, waveplates and Faraday rotators which can be used to construct quasi-optical isolators. Such devices form a catalogue of parts available from the University’s Photonics Innovation Centre.



The picture above shows (clockwise from upper left) a quasi-optical Faraday rotator, a wire grid polariser and a pair of quater wave plates, all manufactured at St Andrews.