Abstract: The present invention discloses a detection device for discriminating between different materials, and a method for doing so. The device comprises an optical system having at least one optical focussing element and a receiving element. The receiving element is sensitive to electromagnetic radiation, typically in the millimeter wave band, and the optical system being arranged to focus incident energy from a scene onto the receiving element. The optical system comprises a prism element having a first surface and a second surface, the first surface being opposite the second surface. At least a portion of the first surface is positioned at an angle ? to the second surface. The angle ? varies between a minimum at a first position on the first surface and a maximum at a second position on the first surface.

Abstract: The present invention discloses a detection device for discriminating between different materials, and a method for doing so. The device comprises an optical system having at least one optical focussing element and a receiving element. The receiving element is sensitive to electromagnetic radiation, typically in the millimetre wave band, and the optical system being arranged to focus incident energy from a scene onto the receiving element. The optical system comprises a prism element having a first surface and a second surface, the first surface being opposite the second surface. At least a portion of the first surface is positioned at an angle ? to the second surface. The angle ? varies between a minimum at a first position on the first surface and a maximum at a second position on the first surface.

Abstract: A superconductive junction (10) comprises a first track (22) of YBa.sub.2 Cu.sub.3 O.sub.7 surmounted by a second track (28) also of YBa.sub.2 Cu.sub.3 O.sub.7. An interconnect (26) in the form of a superconductive mesa electrically connects the first track to the second track and acts as a microbridge. When cooled below a critical temperature, the junction (10) shows Josephson-like behaviour. A non-superconductive layer (24) of PrBa.sub.2 Cu.sub.3 O.sub.7 separates the first track and the second track, with the interconnect extending through the PrBa.sub.2 Cu.sub.3 O.sub.7 layer in the form of an island. The junction (10) is fabricated by electron beam evaporation, optical lithography, and ion beam milling.