Precision interferometry for gravitational wave detection: Current status and future trends

Gravitational wave detectors rely on ultra-high precision interferometry to detect dynamic strains arising from fluctuations in space-time from cataclysmic astrophysical events. The resulting displacements occur on the sub-attometer and smaller levels. To achieve this unprecedented level of measurement precision, kilometer length-scale interferometers have been developed and refined in the past 20 years. Gravitational wave interferometers make use of a broad array of technologies: the world's most stable high power lasers, the most precisely figured mirrors, ultraquiet vibration isolation systems, and sophisticated hierarchical feedback systems. This article explores the physics, engineering, and optical techniques underlying gravitational wave interferometers, and attempts to give the reader a sense of the breadth of science and technology needed to make interferometers perform at these unparalleled levels.