Australian scientists deliver ultra-precise optical coatings for LIGO upgrade

By the Everything Space news desk · 01 Oct 2026 · written from the sources below

Image: Phys.org

The nanometer-level coatings on new beamsplitters aim to boost gravitational wave detector sensitivity for fainter, more distant cosmic signals.

Researchers at the Australian National University have finished a three-year effort to produce specialized optical coatings for two beamsplitters destined for LIGO, the gravitational wave observatory network. The work forms part of a broader upgrade intended to let LIGO detect gravitational waves with greater sensitivity, including weaker signals originating from farther across the universe.

Each beamsplitter is a large glass disk roughly 45 centimeters across and weighing over 20 kilograms, made from exceptionally pure glass. One side carries a coating designed to split a laser beam into two equal halves, while the opposite side receives an ultralow-reflectivity coating said to be far more effective than typical eyeglass coatings, reducing unwanted interference and improving measurement precision.

Achieving this required controlling coating thickness to within a few atomic layers across nearly half a meter of surface, a level of uniformity the team describes as pushing optical manufacturing to its practical limits. According to the researchers, only two groups in the world currently have the capability to produce coatings meeting these standards for gravitational wave detection.

To reach this precision, the ANU team built eight custom automated systems for cleaning, measuring, and handling the optics without direct human contact, since even minor contamination or defects could compromise performance. The work took place in a newly built clean room meeting cleanliness standards comparable to those used in advanced semiconductor fabrication.

LIGO detects gravitational waves—ripples in space-time first predicted by Einstein and directly observed for the first time in 2015—by measuring extraordinarily small distance changes using laser light as a precise ruler. Improving the beamsplitters' optical quality is intended to sharpen that measurement, helping scientists study colliding black holes, neutron stars, and other extreme cosmic events in greater detail.

Written in Everything Space’s own words by our news-desk model from the sources above, and checked against them in code: every number in this report appears in its sources, and no sentence is copied from them.