The discrete sampling variation measurement

2012

Living Rev. Relativ.

168

238

The fast progress in improving the sensitivity of the gravitational-wave detectors, we all have witnessed in the recent years, has propelled the scientific community to the point at which quantum behavior of such immense measurement devices as kilometer-long interferometers starts to matter. The time when their sensitivity will be mainly limited by the quantum noise of light is around the corner, and finding ways to reduce it will become a necessity. Therefore, the primary goal we pursued in this review was to familiarize a broad spectrum of readers with the theory of quantum measurements in the very form it finds application in the area of gravitational-wave detection. We focus on how quantum noise arises in gravitational-wave interferometers and what limitations it imposes on the achievable sensitivity. We start from the very basic concepts and gradually advance to the general linear quantum measurement theory and its application to the calculation of quantum noise in the contemporary and planned interferometric detectors of gravitational radiation of the first and second generation. Special attention is paid to the concept of the Standard Quantum Limit and the methods of its surmounting.

Section: Beating the Sql By Means Of Noise Cancellationmentioning

confidence: 99%

Quantum Measurement Theory in Gravitational-Wave Detectors

2012

Living Rev. Relativ.

168

238

“…Several types of devices have been proposed which can, in principle, provide this sensitivity, in particular: squeezed-based schemes used in solid-state gravitational-wave antennae; microwave speed-meter [18]; small-scale optical speed-meter [21]; spectral variation measurement-based schemes (a.k.a. schemes with modified input-output optics) [11,17]; and the Discrete Sampling Variation Measurement (DSVM) based optical position meter [33]. The first two types require cryogenic equipment.…”

Section: A Options For the Local Metermentioning

confidence: 99%

“…The main goal of the current paper is further development of the optical lever topology towards practical design of the intracavity gravitational-wave detector. In particular, we consider its integration with the local meter based on the Discrete Sampling Variation Measurement (DSVM) procedure [33].…”

Section: Introductionmentioning

confidence: 99%

Practical design of the optical lever intracavity topology of gravitational-wave detectors

2006

Phys. Rev. D

The QND intracavity topologies of gravitational-wave detectors proposed several years ago allow, in principle, to obtain sensitivity significantly better than the Standard Quantum Limit using relatively small anount of optical pumping power. In this article we consider an improved more "practical" version of the optical lever intracavity scheme. It differs from the original version by the symmetry which allows to suppress influence of the input light amplitude fluctuation. In addition, it provides the means to inject optical pumping inside the scheme without increase of optical losses.We consider also sensitivity limitations imposed by the local meter which is the key element of the intracavity topologies. Two variants of the local meter are analyzed, which are based on the spectral variation measurement and on the Discrete Sampling Variation Measurement, correspondingly. The former one, while can not be considered as a candidate for a practical implementation, allows, in principle, to obtain the best sensitivity and thus can be considered as an ideal "asymptotic case" for all other schemes. The DSVM-based local meter can be considered as a realistic scheme but its sensitivity, unfortunately, is by far not so good just due to a couple of peculiar numeric factors specific for this scheme.From our point of view search of new methods of mechanical QND measurements probably based on improved DSVM scheme or which combine the local meter with the pondermotive squeezing technique, is necessary. * Electronic address: stefan@hbar.phys.msu.ru † Electronic address: farid@hbar.phys.msu.ru

“…The small Fabry-Perot cavity attached to the central mirror C is the key element of the scheme. Due to its modest size (compared to 4 km long cavities of large interferometer) it is possible to the use so called Discrete p/ |~p P. Sampling Variation Measurement technique (DSVM) proposed in [5]. This technique allows to measure weak forces acting upon moveable mirror of the local meter with precision significantly higher than SQL.…”

Section: Resultsmentioning

confidence: 99%

“…To detect this effective signal we can use variation measurement. It means that on each time interval T we need to know optimal homodyne phase and filter function that can be found as functions that minimize measurement error functional (see details in [5]). …”

Section: Resultsmentioning

confidence: 99%

Optical quantuma non-demolition meter for gravitational wave detection

Proceedings of CAOL 2005. Second International Conference on Advanced Optoelectronics and Lasers, 2005.

Self Cite

We propose new gravitational wave detector design and new method of measurement that is based on principle of Quantum Non-Demolition (QND) measurement. New design implies the so called "intracavity" measurement of the optical field parameters inside the cavity of interferometer without disturbing light quantum state. It is shown that using a technique called discrete sampling variation measurement (DSVM) in a local meter it is possible to overcome the Standard Quantum Limit by an arbitrary amount limited only by the amount of optical energy circulating in the cavity of local meter and optical losses in the local meter mirrors. This technique being implemented will also be a demonstration of QND measurement and therefore can be used to demonstrate the detector moveable mirrors quantum behaviour.