2006/07/07 by F. Ya. Khalili · 1 citation
Engineering · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Geophysics and Sensor Technology #Pulsars and Gravitational Waves Research #gr-qc
paper · pdf · doi:10.1103/physrevd.75.082003
published as Phys.Rev.D75:082003,2007 · 24 pages, 10 figures, 3 tables
arxiv created 2006/07/07 · openalex publication_date 2007/04/19 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The intracavity topologies of laser gravitational-wave detectors proposed several years ago are the promising way to obtain sensitivity of these devices significantly better than the Standard Quantum Limit (SQL). In essence, the intracavity detector is a two-stage device where the end mirrors displacement created by the gravitational wave is transferred to the displacement of an additional local mirror by means of the optical rigidity. The local mirror positions have to be monitored by an additional local meter. It is evident that the local meter precision defines the sensitivity of the detector. To overcome the SQL, the quantum variational measurement can be used in the local meter. In this method a frequency-dependent correlation between the meter backaction noise and measurement noise is introduced, which allows us to eliminate the backaction noise component from the meter output signal. This correlation is created by means of an additional filter cavity. In this article the sensitivity limitations of this scheme imposed by the optical losses both in the local meter itself and in the filter cavity are estimated. It is shown that the main sensitivity limitation stems from the filter cavity losses. In order to overcome it, it is necessary to increase the filter cavity length. In a preliminary prototype experiment, an approximate 10 m long filter cavity can be used to obtain sensitivity approximately 2--3 times better than the SQL. For future Quantum Non-Demolition (QND) gravitational-wave detectors with sensitivity about 10 times better than the SQL, the filter cavity length should be within kilometer range.