Optical Metrology for Large Telescope Optics

In recent years the demand for meter-scale optical elements has increased significantly, driven by growth in terrestrial and satellite-based astronomy, and defense and security applications. Laser interferometry is used throughout the manufacturing of large optics to ensure conformance to demanding design specifications. More recently, "dynamic interferometry" has been implemented for vibration-insensitive measurement of large optics. The data is used to control polishing operations, verify dimensional stability of support structures, align mirror segments and complete other critical metrology applications.

"Meter-class" describes a category of telescopes with optical elements larger than one meter in diameter, typically operating within the infrared through visible spectra. The primary and secondary optics may be monolithic glass structures or may consist of multiple segments that can be actively aligned. Mirror size is only bounded by current manufacturing methods. At present more than a dozen telescopes are in operation with primary mirrors larger than eight meters, and several more challenging projects are in development.