Abstract: There is provided a filter for filtering electromagnetic radiation, wherein said filter is arranged to transmit electromagnetic radiation of a first predetermined wavelength and to block transmission of electromagnetic radiation of a second, different predetermined wavelength; said filter comprising a first metamaterial. Optionally, the metamaterial may be formed of a plurality of material elements wherein each material element is at least one-dimensional and the size of the material element along each dimension is no greater than the size of the second predetermined wavelength. The filter comprises a second metamaterial arranged to provide second filtering of electromagnetic radiation.

Abstract: There is provided a filter for filtering electromagnetic radiation, wherein said filter is arranged to transmit electromagnetic radiation of a first predetermined wavelength and to block transmission of electromagnetic radiation of a second, different predetermined wavelength; said filter comprising a first metamaterial. Optionally, the metamaterial may be formed of a plurality of material elements wherein each material element is at least one-dimensional and the size of the material element along each dimension is no greater than the size of the second predetermined wavelength. The filter comprises a second metamaterial arranged to provide second filtering of electromagnetic radiation.

Abstract: There is provided a device arranged to couple with an electromagnetic source. The device comprises an optical metamaterial arranged to increase the intensity of radiation at a predetermined optical wavelength. The optical metamaterial has a periodic reflective component having a dimension no greater than the predetermined wavelength.

Abstract: There is provided an optical diode comprising a circular polarisation splitter, a first circular polariser and a second circular polariser. The circular polarisation splitter is arranged to receive at least partially unpolarised light and output right-handed circular polarised light along a first optical path and left-handed circular polarised light along a second optical path. The first circular polariser is arranged on the first optical path and transmits right-handed circular polarised light and reflects left-handed circular polarised light. The second circular polariser is arranged on the second optical path and transmits left-handed circular polarised light and reflects right-handed circular polarised light.

Abstract: There is provided a device arranged to couple with an electromagnetic source. The device comprises an optical metamaterial arranged to increase the intensity of radiation at a predetermined optical wavelength. The optical metamaterial has a periodic reflective component having a dimension no greater than the predetermined wavelength.