A team led by Jonathan Richardson at UC Riverside has developed a method using commercial thermal imaging cameras to correct heat-induced distortions in LIGO's mirrors. The fix addresses a long-standing engineering challenge that limits how far the Laser Interferometer Gravitational-Wave Observatory can detect gravitational waves from distant cosmic events like merging black holes. The approach requires no new technology development, which Richardson notes is unusual for solving LIGO instrumentation problems.
LIGO's twin facilities in Washington and Louisiana use 2.5-mile-long tunnels where laser beams bounce off mirrors to detect gravitational waves passing through Earth. The mirrors absorb a tiny fraction of the intense laser light, converting it to heat that warps the surface by a few nanometers. This distortion reduces the observatory's sensitivity to the cosmic signals scientists are trying to measure. The new technique uses infrared thermal images paired with computer models to map the distortions accurately, allowing corrective heat to be applied with precise targeting.
Once incorporated into LIGO's upcoming upgrade, the team estimates the fix would extend the observatory's detection range by roughly 33 million light-years. While that distance seems modest against cosmic scales, the three-dimensional expansion of space means even modest increases in detection range open up exponentially larger volumes of observable universe. A greater detection range translates directly to discovering more gravitational wave events from violent cosmic collisions currently beyond LIGO's reach.
The technique will also become part of the design for Cosmic Explorer, a proposed next-generation gravitational-wave observatory with 40-kilometer-long arms targeted for the mid-2030s. At 10 times larger than LIGO, Cosmic Explorer is already designed to detect events far beyond current capabilities, and Richardson's method will further extend its sensitivity. A paper describing the technique was published July 16 in Classical and Quantum Gravity.