In 2017, the detection of gravitational waves from the merger of a binary neutron star marked a major breakthrough in physics. These waves revealed crucial information about the Universe, from the origins of short gamma-ray bursts to the formation of heavy elements.
However, capturing gravitational waves from post-merger residues remains a challenge, as these waves evade the reach of current detectors. Yet, they could illuminate the internal structure of neutron stars.
A Kerr-effect-enhanced optical spring showing adjustable non-linearity, offering potential applications for improving the sensitivity of gravitational wave detectors and in various optomechanical systems.
Credit: Tokyo Tech
The solution might lie in amplifying the signal through an optical spring, using the radiation pressure of light to simulate a spring behavior. A team of Japanese researchers from the Tokyo Institute of Technology, led by Associate Professor Kentaro Somiya and Doctor Sotatsu Otabe, proposes an innovation: the Kerr-effect-enhanced optical spring.
To make this system more sensitive without needing more energy, the researchers employ a special technique in an optical device. They introduce a material, called a Kerr medium. This material has the unique property of changing the light's refractive index.
Thanks to this property, the device can act as a stiffer light spring, increasing its ability to respond to very fine variations, such as those caused by gravitational waves, without consuming more energy. Tests have proven that this method makes the light spring 1.6 times stiffer, allowing the device to detect variations at higher frequencies, going from 53 to 67 Hz.
This advance paves the way for next-generation gravitational wave detectors, capable of detecting hitherto elusive waves and providing us with additional keys to the composition of the Universe. The proposed design is simple to implement and introduces an adjustable parameter in optomechanical systems.