Abstract: A system and method of using the same, wherein the system comprises: an optical surface having a diffractive image generating structure disposed thereon, the diffractive image generating structure itself comprising a layer of reflective material incorporating a plurality of grooved diffractive elements each having a periodic wave surface profile, the periodic wave surface profiles each having a groove alignment direction; a source of incident electromagnetic radiation arranged to illuminate the diffractive elements at an angle of incidence substantially normal to the plane of the surface of the diffractive elements; means for polarizing the radiation from the source, and means for polarizing radiation reflected from the diffractive elements; wherein the diffractive elements are configured such that, in use, polarization conversion of the incident radiation takes place, and wherein the diffractive elements are disposed in a two dimensional array of pixels to represent an image; and further wherein the means fo

Abstract: A system and method of using the same, wherein the system comprises: an optical surface having a diffractive image generating structure disposed thereon, the diffractive image generating structure itself comprising a layer of reflective material incorporating a plurality of grooved diffractive elements each having a periodic wave surface profile, the periodic wave surface profiles each having a groove alignment direction; a source of incident electromagnetic radiation arranged to illuminate the diffractive elements at an angle of incidence substantially normal to the plane of the surface of the diffractive elements; means for polarising the radiation from the source, and means for polarising radiation reflected from the diffractive elements; wherein the diffractive elements are configured such that, in use, polarisation conversion of the incident radiation takes place, and wherein the diffractive elements are disposed in a two dimensional array of pixels to represent an image; and further wherein the means fo

Abstract: Some embodiments are directed to an antenna for use in interrogating RFID tags in close proximity thereto. The antenna can include an active element configured to resonate at or close to a frequency required to read an RFID tag, the active element comprising a feed point; and a plurality of passive elements, each passive element being configured to resonate at or around a frequency corresponding to said frequency, the passive elements being arranged around the active element such that the passive elements electromagnetically couple to the active element when the active element is driven by a signal supplied through the feed point.

Abstract: An optical multilayer (1) comprising textured surfaces suitable for use in anti-counterfeiting and/or security applications is described.

Abstract: A method of optimising the sensitivity of surface plasmon ellipsometry (SPE) apparatus used to analyse a surface comprising a conducting film is disclosed. The method includes calculating a sensitivity map of plasmon ellipsometry for the film. The sensitivity map comprises data defining variations in sensitivity of the plasmon ellipsometry apparatus with angle of incidence and polarization angle of polarized light incident on the conducting film for analysis by the apparatus. The method further comprises using the sensitivity map to configure the plasmon ellipsometry apparatus with a combination of the angle of incidence and polarization angle located in a region of substantially maximum sensitivity in the sensitivity map.

Abstract: A method of optimising the sensitivity of surface plasmon ellipsometry (SPE) apparatus used to analyse a surface comprising a conducting film, the method comprising calculating a sensitivity map of SPE for the film, the sensitivity map comprising data defining variations in sensitivity of said SPE apparatus with angle of incidence and polarisation angle of polarised light incident on said film for analysis by said SPE apparatus, and using said sensitivity map to configure said SPE apparatus with a combination of said angle of incidence and polarisation angle located in a region of substantially maximum sensitivity in said sensitivity map.