A method for constructing a cooled optic wherein one or more cavities are milled, drilled or formed using casting or ultrasound laser machining techniques in a single crystal base and filled with porous material having high thermal conductivity at cryogenic temperatures. A non-machined strain-free single...http://www.google.com.au/patents/US5123982?utm_source=gb-gplus-sharePatent US5123982 - Process of making cryogenically cooled high thermal performance crystal optics
