Doubled sensitivity could allow gravitational wave detectors to reach deeper into space June 23, 2016 Please Register or Log in to view the hidden image! A new squeezed vacuum source could make gravitational wave detectors sensitive enough to study neutron stars. Credit: Eric Oelker, Massachusetts Institute of Technology Researchers from the Massachusetts Institute of Technology (MIT) and Australian National University have developed new technology that aims to make the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) even more sensitive to faint ripples in space-time called gravitational waves. Scientists at Advanced LIGO announced the first-ever observation of gravitational waves earlier this year, a century after Albert Einstein predicted their existence in his general theory of relativity. Studying gravitational waves can reveal important information about cataclysmic astrophysical events involving black holes and neutron stars. For millennia, people have used light as a way of viewing the universe. Telescopes magnify what is visible with the naked eye, and newer telescopes use non-visible parts of the electromagnetic spectrum to provide a picture of the universe surrounding us. "There are many processes in the universe that are inherently dark; they don't give off light of any color," said Nergis Mavalvala, part of the MIT Kavli Institute for Astrophysics and Space Research team and a leader of the research team. "Since many of those processes involve gravity, we want to observe the universe using gravity as a messenger." The researchers are planning to add their new squeezed vacuum source to Advanced LIGO in the next year or so. Once implemented, it will improve the sensitivity of the gravitational detectors, particularly at the higher frequencies important for understanding the composition of neutron stars. These extremely dense stars contain the mass of the sun, which has a radius of 700,000 kilometers, within just a 10-kilometer diameter. Read more at: http://phys.org/news/2016-06-sensitivity-gravitational-detectors-deeper-space.html#jCp
https://www.osapublishing.org/optica/abstract.cfm?uri=optica-3-7-682 Ultra-low phase noise squeezed vacuum source for gravitational wave detectors Abstract: Squeezed states of light are a valuable resource for reducing quantum noise in precision measurements. Injection of squeezed vacuum states has emerged as an important technique for reducing quantum shot noise, which is a fundamental limitation to the sensitivity of interferometric gravitational wave detectors. Realizing the most benefit from squeezed-state injection requires lowering optical losses and also minimizing squeezed quadrature fluctuations—or phase noise—to ensure that the large noise in the anti-squeezed quadrature does not contaminate the measurement quadrature. Here, we present an audio band squeezed vacuum source with 1.3+0.7−0.5 mrad of phase noise. This is a nearly tenfold improvement over previously reported measurements, improving prospects for squeezing enhancements in current and future gravitational wave detectors.
