title: Angular instability due to radiation pressure in the LIGO gravitational-wave detector.
abstract: We observed the effect of radiation pressure on the angular sensing and control system of the Laser Interferometer Gravitational-Wave Observatory (LIGO) interferometer's core optics at LIGO Hanford Observatory. This is the first measurement of this effect in a complete gravitational-wave interferometer. Only one of the two angular modes survives with feedback control, because the other mode is suppressed when the control gain is sufficiently large. We developed a mathematical model to understand the physics of the system. This model matches well with the dynamics that we observe.
authors.affiliation: Department of Physics, Syracuse University, Syracuse, New York 13244, USA. eiich.hirose@gmail.com
authors.forename: Eiichi
authors.initials: E
authors.lastname: Hirose
authors.forename: Keita
authors.initials: K
authors.lastname: Kawabe
authors.forename: Daniel
authors.initials: D
authors.lastname: Sigg
authors.forename: Rana
authors.initials: R
authors.lastname: Adhikari
authors.forename: Peter R
authors.initials: PR
authors.lastname: Saulson