Abstract: A rigid radiation reflector is fabricated from a powdered material transparent to light in a wavelength band extending from approximately 0.2 micrometers to at least 8 micrometers. The powdered material is dispersed in a liquid wherein the powdered material is at least 95% insoluble in the liquid. The resulting mixture is molded under pressure at room temperature and then sintered to generate a porous solid. The porous solid is cooled to room temperature. A surface of the porous solid is then coated with a light-reflecting metal.

Abstract: A multi-layer radiation reflector/emitter includes first and second materials. The first material is transparent to radiation in a wavelength spectrum ranging from approximately 0.2 microns to at last 6 microns. The first material is a self-supporting arrangement of randomized particles having an average dimension in a range of approximately 0.2 microns to approximately 0.4 microns and defining a fill factor of approximately 0.1 to approximately 0.5. The second material reflects radiation having a wavelength greater than approximately 2 microns.