Now available from IMTS Laser Specialists , rear mirrors are key optical components in laser resonators or laser cavities.
Typically GaAs, Ge, or ZnSe, rear mirrors are partial reflectors with a very high reflection-to-transmission ratio (99.0% to 99.7%). Like output couplers, rear mirrors are part of the lasing process, and as such high reflectivity is desired.
The rear mirror's slight transmission is used in conjunction with power meters to test for laser resonator output power. When laser resonator designs require rear mirrors to be total reflectors, Si, Cu, or Mo substrates are used.