Mirror for infrared and visible wavelength radiation
 High reflectance mirror 40 for multiple wavelengths has substrate 42 which carries first reflector stack 46 for reflection of the principal, longer wavelength and a stack 66 which reflects shorter wavelength in an alignment beam. Semiconductor layer 64 separates passes the longer wavelength but reflects and/or absorbs the alignment beam of shorter wavelength. Layer 64 thus effectively optically decouples stacks 46 and 66. Each of the layers in the longer wave first reflecting stack 46 is of an optical thickness equal to an odd number of quarter wavelengths of the principal beam. The semiconductor layer 64 and the shorter wavelength reflecting an optical thickness equal to an even number of quarter wavelengths of the principal beam. 
Hughes Aircraft Company
G
G02B
inventional
James E.
Rogers