Reflectance Standards

NIST traceable reflectance standard

The Optical Reference Laboratory is your preferred source for high quality NIST traceable reference mirrors.  These specular reflectance standards exhibit superior surface quality and the highest available spectral accuracy, designed to exceed your most demanding needs.

Vacuum deposited aluminum on glass is the most commonly used specular reflectance standard.  Optical Reference Laboratory offers an aluminum mirror of 1.5 inches in diameter, housed in a convenient screw cap container, as shown here.  The aluminum coating is protected by a thin overcoat.


NIST traceability is provided for the following options:

  • Incident angles of 8, 30, and 45 degrees
  • S and P polarizer orientations
  • Wavelength range 250-2500 nm 


The mirrors can be calibrated at angles other than those listed above, without NIST certification.  Your mirror in good condition can be calibrated and certified within these parameters.

Double Calibration Process

For Superior Accuracy

The standard mirrors are calibrated against a NIST traceable reference.  Their accuracy is also checked further using low loss laser cavity ring down (CRD) mirrors.  

Aluminum mirror reflectance at 8 degrees incidence
Aluminum mirror reflectance at 45 degrees incidence

These mirrors exhibit 99.99 %R or better over specific wavelength ranges, so they can serve as essentially 100% reference points during the calibration process.  Standards must pass the NIST and the CRD calibration checks before being issued a calibration certificate, providing a level of spectral accuracy not available elsewhere.  Please view the application page about low loss mirrors and contact Optical Reference Lab for further details and a discussion of uncertainty determinations.