We can produce plano optical metallic mirror(Metal-coated mirrors) by magenetron sputtering 

Magnetron sputtering plating gold, silver, copper, nickel, aluminum, titanium, chromium, etc., the maximum processing size can reach 500mm, the uniformity is better than ±5%, and the environmental testing meets the requirements. Thin films using the magnetron sputtering process are characterized by good adhesion, high reflectivity, friction resistance, and strong environmental adaptability. They can be widely used in military and civilian optoelectronic equipment such as lasers and optical system components.

Figure1: gold metallic mirror

Figure2:Silver Metallic Mirror

Figure3:Copper Metallic Mirror