A new laser breakthrough to help understand gravitational waves

Gravitational wave scientists at the University of Western Australia have led the development of a new laser-mode sensor of unprecedented precision that will be used to probe the interiors of neutron stars and test the fundamental limits of general relativity.

Research Associate of the UWA Center of Excellence for the Discovery of Gravitational Waves (OzGrav-UWA), Dr Aaron Jones said that UWA has coordinated a worldwide collaboration of experts in gravitational waves, metasurface and photonics to launch a new method of measuring structures of light called “eigenmodes”.

“Gravitational wave detectors like LIGO, Virgo and KAGRA store a huge amount of optical power and multiple pairs of mirrors are used to increase the amount of laser light stored along the massive arms of the detector,” said Dr Jones.

“However, each of these pairs has small distortions that scatter light away from the perfect shape of the laser beam, which can cause excessive noise in the detector, limit sensitivity, and knock the detector off line.

“We wanted to test an idea that would allow us to zoom in on the laser beam and look for small power ‘tremors’ that can limit the sensitivity of detectors.”

Dr Jones said a similar problem is being faced in the telecommunications industry where scientists are investigating ways to use multiple eigenmodes to carry more data over fiber optics.

“Telecom scientists have developed a way to measure eigenmodes using a simple device, but it’s not sensitive enough for our purposes,” he said. “We came up with the idea of ​​using a metasurface – an ultra-thin surface with a special pattern encoded in a size below the wavelength – and reached out to collaborators who could help us create one.”

The proof-of-concept configuration developed by the team was more than a thousand times more sensitive than the original device developed by the telecommunications scientists and the researchers will now seek to translate this work into gravitational wave detectors.

Associate Professor Chunnong Zhao, Chief Researcher of OzGrav-UWA, said the development is another step forward in detecting and analyzing the information carried by gravitational waves, allowing us to observe the universe from new ways.

“Solving the mode detection problem in future gravitational wave detectors is essential if we are to understand the interiors of neutron stars and deepen our observation of the universe in a way never before possible,” said the professor. aggregate Zhao.

The study has been accepted for publication in Physical examination A.