Advanced LIGO: the next generation of gravitational wave detectors

TLDR

Advanced LIGO will replace initial LIGO as the next‑generation gravitational‑wave detector. Advanced LIGO achieves ten‑fold better strain sensitivity down to 10 Hz by upgrading seismic isolation, suspensions, optics, and laser subsystems, with ongoing research into further enhancements. Construction is underway, and the improved sensitivity is expected to enable detections and rich astrophysics across most gravitational‑wave categories.

Abstract

The Advanced LIGO gravitational wave detectors are next generation instruments which will replace the existing initial LIGO detectors. They are currently being constructed and installed. Advanced LIGO strain sensitivity is designed to be about a factor 10 better than initial LIGO over a broad band and usable to 10 Hz, in contrast to 40 Hz for initial LIGO. This is expected to allow for detections and significant astrophysics in most categories of gravitational waves. To achieve this sensitivity, all hardware subsystems are being replaced with improvements. Designs and expected performance are presented for the seismic isolation, suspensions, optics and laser subsystems. Possible enhancements to Advanced LIGO, either to resolve problems that may arise and/or to allow for improved performance, are now being researched. Some of these enhancements are discussed along with some potential technology being considered for detectors beyond Advanced LIGO.