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We also use interferometry to measure wedge of flat laser mirrors to ensure parallelism.

Results can be reported in many different forms, such as ISO 10110, Zernike polynomials, or graphically

LASER MIRROR INTERFEROMETRY

The specifications of most laser mirror surfaces involve sub micrometer dimensions, too small to measure mechanically. Interferometry uses laser light to generate interference patterns that can be interpreted to measure the flatness, radius of curvature, or angle of a laser optic as well as other properties.

LBP Phase shifting interferometer

For the majority of CO2 laser mirrors a Phase shifting interferometer is used for quality assurance. With software analysis of the interference pattern, a hard copy of the results is available to customers. This demonstrates that surface form specifications such as power and irregularity have been met.

A typical CO2 laser mirror interferogram 633nm wavelength phase shifting interferometer.

This measurement of the spacing and curvature of the black and white lines (or “fringe pattern”) can be used to interpret the optical flatness of the laser mirror.

It is also useful to measure and align optical assemblies such as reflective beam expanders, or collimators, with an interferometer.

Of great interest has been investigating the mounting of optics, and observing the deformation that can occur with poorly designed mounts, or excessive mechanical force. We can supply mirrors complete with mounts, and water cooled laser mirrors checked by interferometer that the assembled mirror has not been deformed.