High efficiency reflective optical system

摘要

Highly efficient reflective optical system that perfectly reflects incident electromagnetic radiation of a certain spectra and almost perfectly reflects radiation of another spectra. Incident electromagnetic radiation having a wavelength above a critical wavelength is relatively perfectly reflected. The critical wavelength is determined by the critical temperature of a high temperature superconductor material incorporated in the optical system. A preferred embodiment includes a cryogenically cooled substrate to which is applied a coating of a noble metal such as silver. A layer of a high temperature superconductor material is applied over the coating of noble metal. Since the critical wavelength of the incident radiation is inversely proportional to the critical temperature of the superconducting material, the use of high temperature superconductor material in the optical system provides a critical wavelength whereby certain spectra of an incident radiation is perfectly reflected. Since the effective emissivity of the optical system is very low for the same reason, the radiation heat transfer to cold objects (colder than the critical temperature of the superconductor) can be substantially decreased. Applications for such highly reflective optical systems provide for reducing radiation heat transfer for the tanks containing cryogens in space vehicles, for internal radiation shields for cryogenic dewars, as radiation insulation for lunar or orbiting space stations, to produce a thermal radiation shield for superconducting magnet systems, and as components in special purpose optical systems.