RUI: Investigating Ice Formation on Optical Surfaces and Material Properties for Cryogenic Gravitational Wave Detectors

Western Washington University, Bellingham WA

Investigators

Abstract

This award supports research in relativity and relativistic astrophysics, and it addresses the priority areas of NSF's "Windows on the Universe" Big Idea. A few years ago, and a century after the existence of gravitational waves was predicted by Einstein's theory of general relativity, the NSF-funded Laser Interferometer Gravitational-Wave Observatory (LIGO) achieved the first detection of such distortions of spacetime caused by merging black holes or neutron stars. This discovery opened a new window into the universe and gave rise to the new field of gravitational wave astronomy. To help deliver on the promise of this new field, this award will support the development of new detectors with extended reach and sensitivity using optics cooled to very low temperatures. Specifically, it will fund research to better understand and overcome problems arising when ice layers form on the surfaces of cold optics and change their carefully designed properties. By providing research opportunities to undergraduate students at Western Washington University, a primarily undergraduate institution, the project will allow them to acquire transferable skills in preparation for future careers both in and outside of academia. The award will deepen our understanding of the universe by supporting new discoveries in gravitational wave astronomy, and it will contribute to a globally competitive workforce in the STEM (science, technology, engineering, and mathematics) field, both by training students and through outreach efforts to the public. This award will fund instrument science research at Western Washington University to support the development of next-generation gravitational wave detectors with increased reach and sensitivity. Specifically, it will address the problem of ice formation on cold mirrors in cryogenic gravitational wave detectors. This issue has emerged as a significant challenge for KAGRA, and it has the potential to be even more problematic in proposed future cryogenic gravitational wave detectors like LIGO Voyager or the Einstein Telescope. Students and the PI will develop a modular optical cryostat suitable for measurements at 120K, the planned operating temperature of LIGO Voyager. The group will use this cryostat to study cryogenic ice layers on cold optical surfaces, with the aim of better understanding their properties, their impact on cryogenic gravitational wave detectors, and possible mitigation strategies. The instrument to be built will also enable further follow-up projects related to optical materials for cryogenic gravitational wave detectors. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.