The Glasgow 10 m prototype laser interferometric gravitational wave detector

Abstract

We present a description of the prototype interferometric gravitational wave detector at Glasgow. The detector, which has been under development for a number of years, consists of two perpendicular 10-m-long high finesse Fabry–Perot cavities formed between test masses hung as pendulums and is illuminated with a cw argon ion laser. The differential displacement sensitivity of the detector is ∼7×10−19 m/√Hz from 500 Hz → 3 kHz and is close to being limited by photoelectron shot noise in the detected photocurrent.

Gravitational Wave Detection by Interferometry (Ground and Space)

“…With these constraints in mind, laser development has concentrated on argon-ion lasers and Nd:YAG lasers. Argon-ion lasers emitting light at 514 nm have been used to illuminate several interferometric gravitational wave detector prototypes, see for example [91, 77]. They have an output power in the required single spatial (TEM00q) mode of operation typically of around several Watts, sufficient for this type of laser to have been proposed as the initial laser for a full-scale interferometric detector [103].…”

“…Prototype detectors using laser interferometry have been constructed by various research groups around the world — at the Max-Planck-Institut für Quantenoptik in Garching [91], at the University of Glasgow [77], at California Institute of Technology [1], at the Massachusets Institute of Technology [33], at the Institute of Space and Astronautical Science in Tokyo [67] and at the astronomical observatory in Tokyo [3]. These detectors have arm lengths varying from 10 m to 100 m and have or had either multibeam delay lines or resonant Fabry-Perot cavities in their arms.…”

Gravitational Wave Astronomy

“…The first working laser interferometer, built by Forward (16), was 2 m in arm length and achieved 10 −16 strain sensitivity in a 1 Hz bandwidth at 1 kHz. Subsequent advanced versions, using improved laser stability, optics, and isolation from background seismic noise, were built at Caltech (17), the University of Glasgow (18), and Garching (19). They were 40, 10, and 30 m in length and achieved strain sensitivities at several hundred hertz in a 100 Hz bandwidth of about 10 −19 , 10 −18 , and 10 −18 , respectively.…”

Gravitational wave detectors on the earth

“…In 1977 the Department of Physics and Astronomy of the University of Glasgow began also to study laser interferometry for gravitational radiation detection [27], and in 1980 started operation of a 10 m prototype. In 1985 the Garching group proposed the construction of a large detector with 3 km arm, the British group an equivalent project in 1986.…”