Patent ID: 8861087

Claim:
A multi-layer photonic structure comprising alternating layers of high index material and low index material having a form [0.5 L H (LH) N 0.5 L] where H is a layer of high index material, L is a layer of low index material, 0.5 L are half layers of low index dielectric material positioned on a top and a bottom of the multilayer photonic structure, and N is a number of pairs of layers of high index material and layers of low index material, wherein: N is an integer≧1; the low index dielectric material has an index of refraction n L from about 1.3 to about 2.5; the high index dielectric material has an index of refraction n H of greater than or equal to about 3.0, wherein n H >n L , and the half layers of low index dielectric material pass visible wavelengths of light and reflect UV and IR wavelengths of light such that the multilayer photonic structure is substantially transparent to visible wavelengths of light and has an IR reflectivity band and a UV reflectivity band, wherein a reflectance of the multilayer photonic structure is about 100% within the IR reflectivity band and within the UV reflectivity band for light having angles of incidence from about 0 degrees to about 80 degrees relative to the multi-layer photonic structure; and the multi-layer photonic structure has a range to mid-range ratio greater than about 20% in a transverse electric mode and a transverse magnetic mode, and wherein the range to mid-range ratio for the transverse electric mode is determined by η TE = 2 ⁢ ⁢ λ long TE ⁢ ( θ 0 = 90 ⁢ ° ) - λ Short TE ⁡ ( θ 0 = 0 ⁢ ° ) λ long TE ⁡ ( θ 0 = 90 ⁢ ° ) + θ Short TE ⁡ ( θ 0 = 0 ⁢ ° ) , where λ long TE is a first band edge for a first long wavelength in the transverse electric mode and A λ short TE is a second band edge for a first short wavelength in the transverse electric mode, and the range to mid-range ratio for the transverse magnetic mode is determined by η TM = 2 ⁢ ⁢ λ long TM ⁢ ( θ 0 = 90 ⁢ ° ) - λ Short TM ⁡ ( θ 0 = 0 ⁢ ° ) λ long TM ⁡ ( θ 0 = 90 ⁢ ° ) + θ Short TM ⁡ ( θ 0 = 0 ⁢ ° ) , where λ long TM is a third band edge for a second long wavelength in the transverse magnetic mode and λ short TM is a fourth band edge for a second short wavelength in the transverse magnetic mode.