The Invar Mounted Ultra-Stable Hard Mounted Retroreflector USHM, is the ultimate in shock and vibration resistance. It is vacuum compatible, thermally stable and tailored to applications where extreme shock and vibration are a concern. 



    • Invar steel mounting for exceptional stability and accuracy. 
    • Performs well in harsh environmental applications.
    • Can customize mount and material.
    • Available in custom configurations and with a variety of coatings.
    • Custom "Knife Edge" design option available upon request, enhances beam quality, eliminates the cause of obscuration.
    • PLX is a registered ISO 9001 company

Retrorelector Selector Chart

Coating Specification Chart


Hollow Retroreflectors

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The improved ultra-stable USHM solidly connects the Retroreflector to the next assembly. 

Stability and Accuracy

PLX’s improved USHM’s robust mountings and mirror technology offer properties which enable them to perform exceptionally well in critical applications and harsh conditions. Customized USHM configurations have been utilized in military and space applications and are especially well suited for interferometers where high stability of the OPD and concentricity of the apex on the mounting thread are critical requirements. For special applications PLX can substitute other materials for the Invar mount.


Standard USHM mirror coatings are aluminum, silver and gold, in both bare metal and with protective overcoats. All protected PLX coatings meet MIL-SPEC durability and adhesion requirements. Unprotected metallic coatings work well for interferometric applications. Custom coatings are available.

Custom configurations for specialized applications

PLX engineers can create a custom USHM for your application. Potential variations include smaller and larger apertures, dielectric mirror coatings for high-powered lasers, and units able to withstand military and space environments.

Retroreflector Selector Chart

Specification Chart
Model Clear Aperture
Beam Deviation
USHM-10 USHM-10 1.0/25 1.0 - 30.0 0.15 - 3.50 34
USHM-15 USHM-15 1.5/38 0.5 - 30.0 0.10 - 5.25 73
USHM-20 USHM-20 2.0/50 0.5 - 30.0 0.15 - 7.00 126 - 136
USHM-25 USHM-25 2.5/63 0.5 - 30.0 0.25 - 9.00 206 - 227
USHM-50 USHM-50 5.0/127 0.5 - 30.0 0.45 - 18.0 639 - 855
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