| 摘要 |
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 for polarising is arranged to pass incident radiation having a polarisation state of approximately 45° azimuth to the groove alignment direction, and is arranged to select a polarisation, using the means for polarising the radiation reflected from the diffractive elements, and to pass radiation of the selected polarisation to a detection point. |
