| 摘要 |
<p>A surface capable of supporting surface charge oscillations and exhibiting a profiled grating, said profile comprising at least two superposed periodic profiles. The surface has applications as radar absorber and authentication devices. Also disclosed is a method of detecting the authenticity of an object comprising providing a surface as described above claim adjacent to or on the object, illuminating said surface with radiation from at least one angle and determining the reflectivity characteristics and comparing this with reflectivity characteristics of a reference surface.</p> |
