A method of fabricating a filter for filtering ultraviolet to infrared electromagnetic radiation, said filter combining: a first metamaterial having sub-wavelength properties and arranged to provide first filtering of electromagnetic radiation incident at a first angle in a first range of angles; and a second metamaterial having sub-wavelength properties and arranged to provide second filtering of electromagnetic radiation at a second angle in a second range of angles, wherein the first and second angles are different and the first and second ranges of angles partially overlap and wherein the first metamaterial and second metamaterial are configured as stacked layers of the filter, wherein the first filtering comprises blocking electromagnetic radiation at a first frequency bandwidth about a first wavelength and the second filtering comprises blocking electromagnetic radiation at a second frequency bandwidth about the first wavelength, wherein the second frequency bandwidth is substantially similar to the first frequency bandwidth and wherein the first and second frequency bandwidths are within the ultraviolet to infrared spectrum, while each of the first and second metamaterials transmit ultraviolet to infrared electromagnetic radiation that is not in the first or second frequency bandwidth about the first wavelength; wherein the filter is comprised in a film; and wherein the first metamaterial is a Bragg reflector or a photonic crystal and the second metamaterial is a Bragg reflector or a photonic crystal, the method comprising: selecting the size, shape, material or configuration of the structural features of the first and/or second metamaterial to provide the correct material properties to achieve said blocking within the ultraviolet to infrared electromagnetic spectrum wherein the selecting comprises optimising the filter, to improve multi-angle performance, by monitoring optical properties of the combined filter at multiple angles of incidence whilst adjusting the sub-wavelength properties of the first and second metamaterials. a first metamaterial having sub-wavelength properties and arranged to provide first filtering of electromagnetic radiation incident at a first angle in a first range of angles; and a second metamaterial having sub-wavelength properties and arranged to provide second filtering of electromagnetic radiation at a second angle in a second range of angles, wherein the first and second angles are different and the first and second ranges of angles partially overlap and wherein the first metamaterial and second metamaterial are configured as stacked layers of the filter, wherein the first filtering comprises blocking electromagnetic radiation at a first frequency bandwidth about a first wavelength and the second filtering comprises blocking electromagnetic radiation at a second frequency bandwidth about the first wavelength, wherein the second frequency bandwidth is substantially similar to the first frequency bandwidth and wherein the first and second frequency bandwidths are within the ultraviolet to infrared spectrum, while each of the first and second metamaterials transmit ultraviolet to infrared electromagnetic radiation that is not in the first or second frequency bandwidth about the first wavelength; wherein the filter is comprised in a film; and wherein the first metamaterial is a Bragg reflector or a photonic crystal and the second metamaterial is a Bragg reflector or a photonic crystal, the method comprising: selecting the size, shape, material or configuration of the structural features of the first and/or second metamaterial to provide the correct material properties to achieve said blocking within the ultraviolet to infrared electromagnetic spectrum wherein the selecting comprises optimising the filter, to improve multi-angle performance, by monitoring optical properties of the combined filter at multiple angles of incidence whilst adjusting the sub-wavelength properties of the first and second metamaterials.