The Ultra Stable Hard Mounted Hollow Retroreflector (USHM), from Laser Components, is a self-compensating mirror that is totally insensitive to position and movement, such as tilt and rotation. Parallel incident light falling on the USHM will be reflected back with great accuracy regardless of the USHM's physical orientation.
The USHM is an improved hard mount solidly connecting the retroreflector to the next assembly. It is vacuum compatible and can be positioned about the permanently connected post in any orientation, providing greater freedom for different mounting configurations.
The USHM offers properties, which enable it to perform well in critical applications, such as military, aerospace, or any OEM requirements. It is especially well suited for interferometers where high stability of the OPD and the concentricity of the apex with respect to the mounting thread are critical requirements. USHMs can also be provided in matched pairs for better modulation.
Standard USHM mirror coatings are aluminium, silver and gold, in both bare metal and with protective overcoats. All protected coatings meet MIL-SPEC durability and adhesion requirements. Unprotected metallic coatings are especially suited to interferometric applications. Custom coatings are available.