First demonstration of 6 dB quantum noise reduction in a kilometer scale gravitational wave observatory
Abstract
Photon shot noise, arising from the quantum-mechanical nature of the light, currently limits the sensitivity of all the gravitational wave observatories at frequencies above one kilohertz. We report a successful application of squeezed vacuum states of light at the GEO\,600 observatory and demonstrate for the first time a reduction of quantum noise up to dB in a kilometer-scale interferometer. This is equivalent at high frequencies to increasing the laser power circulating in the interferometer by a factor of four. Achieving this milestone, a key goal for the upgrades of the advanced detectors, required a better understanding of the noise sources and losses, and implementation of robust control schemes to mitigate their contributions. In particular, we address the optical losses from beam propagation, phase noise from the squeezing ellipse, and backscattered light from the squeezed light source. The expertise gained from this work carried out at GEO 600 provides insight towards the implementation of 10 dB of squeezing envisioned for third-generation gravitational wave detectors.
Keywords
Cite
@article{arxiv.2005.10292,
title = {First demonstration of 6 dB quantum noise reduction in a kilometer scale gravitational wave observatory},
author = {James Lough and Emil Schreiber and Fabio Bergamin and Hartmut Grote and Moritz Mehmet and Henning Vahlbruch and Christoph Affeldt and Marc Brinkmann and Aparna Bisht and Volker Kringel and Harald Lück and Nikhil Mukund and Séverin Nadji and Borja Sorazu and Kenneth Strain and Michael Weinert and Karsten Danzmann},
journal= {arXiv preprint arXiv:2005.10292},
year = {2021}
}