Plane mirrors

Renishaw supplied plane mirrors are manufactured on a low thermal expansion glass substrate and have a hard oxide, dielectric coating.

Features and benefits

  • Thermally stable – manufactured on a low thermal expansion substrate minimises errors due to environmental variations.
  • Highly reflective – highly reflective mirror surface (>97%) for the ultimate performance.
  • Easy to mount – Renishaw mirror mounts provide an easy set up and alignment solution.


Cross section 25 mm x 25 mm
Optical aperture 60 mm to 380 mm (10 mm increments)


 Local flatness  < λ/10 over area 12 mm wide x 7 mm high ( λ = 633 nm)
 Total flatness  < λ/10 per 100 mm, <0.5 µm per 500 mm
 Cross polarisation  < 0.5%
 Reflectivity  > 97% of incident beam
 Material  Low thermal expansion glass

Due to their custom configuration and dimensions, plane mirrors are special order items only and therefore may be subject to longer lead times and minimum order quantities.  Alternatively, the data sheet at the bottom of the page gives specifications to allow sourcing locally.

Mirror mounts

To enable mirrors to be mounted and correctly aligned to the motion system, Renishaw can also provide adjustable mounts for use with mirrors up to 350 mm in length, which have a cross section of 25 mm x 25 mm.

These mounts provide up to ±2.5° yaw adjustment and ±1° pitch adjustment. (Actual adjustment range is dependent on mirror length).

Features and benefits

  • Easy to align – in-built pitch and yaw adjustment to accelerate the mirror alignment process.
  • Stable mounting – to provide a stable foundation for the mirror whilst allowing it to thermally expand as required.
  • Non-restrictive – only clamping the mirror securely on two faces reduces the stress through the mirror, minimising the risk of bending the mirror once mounted.

Renishaw supplied mirror mounts are not vacuum compatible.

Mirrors and accessories