Collaborative Research: Enabling Megawatt Optical Power in Cosmic Explorer

Gravitational-wave astronomy has opened a new window on the universe. A century after Einstein predicted gravitational waves, the Laser Interferometer Gravitational-wave Observatory (LIGO) has rewarded decades of investment with the first direct observations of gravitational waves from merging black holes and neutron stars. Cosmic Explorer, a concept for a next-generation gravitational-wave observatory in the United States, aims to push the reach of gravitational-wave astronomy to the edge of the observable universe, using proven LIGO technology in a ten times larger facility. Cosmic Explorer will enable transformative discoveries across physics, astronomy, and cosmology, by observing black holes and neutron stars across cosmic time, probing the nature of the most extreme matter in the universe, and exploring questions in gravity and fundamental physics. This award supports research to design an adaptive optical sensing and controls system critical to enabling Cosmic Explorer. The success of Cosmic Explorer will reshape the field of gravitational-wave astrophysics and the futures of current early-career researchers. By clearing a key technological hurdle towards its realization, this award will ensure that gravitational-wave science continues inspiring young scientists across the country to fulfill their potential as the world-leading researchers of the future. To achieve its unprecedented sensitivity, Cosmic Explorer will require much higher circulating laser power (1.5 MW) than has ever been demonstrated in a large interferometer. The objective of this work is to enable laser interferometry at the megawatt scale, by developing the initial design of a Mode Sensing and Control system for Cosmic Explorer capable of overcoming the thermally-induced optical aberrations that limit current detectors. Specifically, Cosmic Explorer’s thermal compensation requirements will be modeled, documenting the degree to which known sources of wavefront error must be sensed and corrected to achieve the detector design sensitivity. Then, current and emerging technological options will be comprehensively assessed, making down-selections where possible, to deliver a detector subsystem conceptual design for optical mode sensing and control. This work supported by this award will feed into the overall detector design, ahead of a conceptual design review anticipated to take place roughly five years from the award start date. 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.