Optical coating for reflecting visible and longer wavelength radiation having grazing incidence angle

A coated optical reflector reflective of electromagnetic radiation having grazing incidence, including:

• a substrate having a top face and a bottom face, and substantially parallel indentations in at least one of the top face and the bottom face, wherein the indentations define thin portions of the substrate, each of the thin portions separates two relatively thick portions of the substrate, and the thin portions are sufficiently thin to enable the substrate to be folded along said indentations;
• and
• an optical coating on the top face, wherein the optical coating comprises a multi-layer stack of alternating high and low refractive index dielectric layers, wherein the substrate has a left face and a right face, wherein the indentations include top indentations in the top face, and wherein the top indentations are shaped such that when the substrate has been folded along the indentations so that the left face meets the right face, the folded substrate encloses a main volume, and each of the top indentations defines a region separate from the main volume.

A coated optical reflector reflective of electromagnetic radiation having grazing incidence, including:

• a substrate having a top face and a bottom face, and substantially parallel indentations in at least one of the top face and the bottom face, wherein the indentations define thin portions of the substrate, each of the thin portions separates two relatively thick portions of the substrate, and the thin portions are sufficiently thin to enable the substrate to be folded along said indentations, wherein the substrate is a metal extrusion;
• and
• an optical coating on the top face wherein the optical coating comprises a multi-layer stack of alternating high and low refractive index dielectric layers.

An optical reflector, including:

• a substrate reflective of electromagnetic radiation having a first wavelength;
• and
• a multi-layer stack of dielectric layers on the substrate, wherein at least one of the layers has a refractive index different than that of at least another one of the layers, and wherein each of the layers has a matched optical thickness for enhancing overall reflectivity of the optical reflector to electromagnetic radiation having a second wavelength, where the first wavelength is longer than the second wavelength, and wherein the stack has an overall matched optical thickness for enhancing reflection of radiation having the first wavelength.