Test mass materials for a new generation of gravitational wave detectors
21 Feb 2003-Astronomical Telescopes and Instrumentation (International Society for Optics and Photonics)-Vol. 4856, pp 292-297
TL;DR: In this paper, the thermo-mechanical properties of silicon are discussed and the potenial benefits from using silicon as a mirror substrate material in future gravitational wave detectors are outlined.
Abstract: To obtain improved sensitivities in future generations of interferometric graviational wave detectors, beyond those proposed as upgrades of current detectors, will require different approaches in different portions of the gravitational wave frequency band. However the use of silicon as an interferometer test mass substrate, along with all-reflective interferometer topologies, could prove to be a design enabling sensitivity improvements at both high and low frequencies. In this paper the thermo-mechanical properties of silicon are discussed and the potenial benefits from using silicon as a mirror substrate material in future gravitational wave detectors are outlined.
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TL;DR: The Advanced LIGO gravitational wave detectors (ALGWR) as mentioned in this paper are the next generation instruments which will replace the existing initial LIGA detectors and are currently being constructed and installed.
Abstract: The Advanced LIGO gravitational wave detectors are next generation instruments which will replace the existing initial LIGO detectors. They are currently being constructed and installed. Advanced LIGO strain sensitivity is designed to be about a factor 10 better than initial LIGO over a broad band and usable to 10 Hz, in contrast to 40 Hz for initial LIGO. This is expected to allow for detections and significant astrophysics in most categories of gravitational waves. To achieve this sensitivity, all hardware subsystems are being replaced with improvements. Designs and expected performance are presented for the seismic isolation, suspensions, optics and laser subsystems. Possible enhancements to Advanced LIGO, either to resolve problems that may arise and/or to allow for improved performance, are now being researched. Some of these enhancements are discussed along with some potential technology being considered for detectors beyond Advanced LIGO.
1,217 citations
TL;DR: The main theme of this review is a discussion of the mechanical and optical principles used in the various long baseline systems in operation around the world — LIGO, Virgo, TAMA300 and LCGT, and GEO600 — and in LISA, a proposed space-borne interferometer.
Abstract: Significant progress has been made in recent years on the development of gravitational wave detectors. Sources such as coalescing compact binary systems, low-mass X-ray binaries, stellar collapses and pulsars are all possible candidates for detection. The most promising design of gravitational wave detector uses test masses a long distance apart and freely suspended as pendulums on Earth or in drag-free craft in space. The main theme of this review is a discussion of the mechanical and optical principles used in the various long baseline systems being built around the world — LIGO (USA), VIRGO (Italy/France), TAMA 300 (Japan) and GEO 600 (Germany/UK) — and in LISA, a proposed space-borne interferometer.
246 citations
Cites background from "Test mass materials for a new gener..."
...Low-frequency sensitivity is expected to be achieved through the use of separate low-power interferometers with silicon optics operating at cryogenic temperatures [268, 261]....
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01 Jan 2005
TL;DR: The thermo-mechanical properties of silicon make it of significant interest as a possible material for mirror substrates and suspension elements for future long-baseline gravitational wave detectors.
Abstract: The thermo-mechanical properties of silicon make it of significant interest as a possible material for mirror substrates and suspension elements for future long-baseline gravitational wave detectors. The mechanical dissipation in 92 μm thick 〈110〉 single-crystal silicon cantilevers has been observed over the temperature range 85 K to 300 K, with dissipation approaching levels down to ϕ=4.4×10−7.
81 citations
Cites background from "Test mass materials for a new gener..."
...he high thermal conductivity of a silicon mirror substrate would allow circulating powers approximately seven times higher than could be supported by sapphire for the same induced surface deformation [4] making silicon of significant interest as a test mass substrate from a thermal loading standpoint. At room temperature the thermal noise resulting from thermo-elastic effects in interferometers using...
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...ed sapphire test masses and suspension fibers for use in a transmissive Fabry-Perot based interferometer [2,3], and in Europe and the US research on the use of silicon at low temperatures is underway [4,5]. At higher frequencies (greater than a few 100 Hz) the performance of current interferometers is not limited by thermal noise from the optics but by photo-electron shot noise, whose significance can ...
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TL;DR: The thermo-mechanical properties of silicon make it of significant interest as a possible material for mirror substrates and suspension elements for future long-baseline gravitational wave detectors as mentioned in this paper.
79 citations
TL;DR: An improvement is demonstrated with respect to the lowest so far reported optical absorption of amorphous silicon at near-infrared wavelengths with a combination of heat treatment, final operation at low temperature, and a wavelength of 2 μm instead of the more commonly used 1550 nm.
Abstract: Thermal noise of highly reflective mirror coatings is a major limit to the sensitivity of many precision laser experiments with strict requirements such as low optical absorption. Here, we investigate amorphous silicon and silicon nitride as an alternative to the currently used combination of coating materials, silica, and tantala. We demonstrate an improvement by a factor of $\ensuremath{\approx}55$ with respect to the lowest so far reported optical absorption of amorphous silicon at near-infrared wavelengths. This reduction was achieved via a combination of heat treatment, final operation at low temperature, and a wavelength of $2\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ instead of the more commonly used 1550 nm. Our silicon-based coating offers a factor of 12 thermal noise reduction compared to the performance possible with silica and tantala at 20 K. In gravitational-wave detectors, a noise reduction by a factor of 12 corresponds to an increase in the average detection rate by three orders of magnitude ($\ensuremath{\approx}{12}^{3}$).
48 citations
References
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Book•
15 Feb 1986
TL;DR: In this paper, a virtual encyclopedia of theoretical formulas, experimental techniques, and practical lore derived from twenty-five years of experience is provided for the experimenter who wishes to construct near-perfect instrumentation, providing information on the role of phonon-phonon scattering as a fundamental source of dissipation.
Abstract: Electromagnetic and mechanical oscillators are crucial in such diverse fields as electrical engineering, microwave technology, optical technology, and experimental physics. For example, such oscillators are the key elements in instruments for detecting extremely weak mechanical forces and electromagnetic signals are essential to highly stable standards of time and frequency. The central problem in developing such instruments is to construct oscillators that are as perfectly simple harmonic as possible; the largest obstacle is the oscillator's dissipation and the fluctuating forces associated with it. This book, first published in Russian in 1981 and updated with new data for this English edition, is a treatise on the sources of dissipation and other defects in mechanical and electromagnetic oscillators and on practical techniques for minimizing such defects. Written by a team of researchers from Moscow State University who are leading experts in the field, the book is a virtual encyclopedia of theoretical formulas, experimental techniques, and practical lore derived from twenty-five years of experience. Intended for the experimenter who wishes to construct near-perfect instrumentation, the book provides information on everything from the role of phonon-phonon scattering as a fundamental source of dissipation to the effectiveness of a thin film of pork fat in reducing the friction between a support wire and a mechanically oscillating sapphire crystal. The researchers that V. B. Braginsky has led since the mid-1960s are best known in the West for their contributions to the technology of gravitational-wave detection, their experimental search for quarks, their test of the equivalency principle, and their invention of new experimental techniques for high-precision measurement, including "quantum nondemolition movements." Here, for the first time, they provide a thorough overview of the practical knowledge and experimental methods that have earned them a worldwide reputation for ingenuity, talent, and successful technique.
319 citations
TL;DR: The performance of thermally distorted interferometers is treated quantitatively, and the two schemes for increasing the optical path, the delay-line and Fabry-P\'erot methods, are compared.
Abstract: The ultimate sensitivity of interferometric gravitational-wave detectors requires extremely high light powers sensing the separation of test masses. Absorption of light at the optical components causes wave-front distortions via the thermally deformed substrates or via thermal lensing. The performance of thermally distorted interferometers is treated quantitatively, and the two schemes for increasing the optical path, the delay-line and Fabry-P\'erot methods, are compared.
215 citations
TL;DR: In this article, thermal expansion coefficients of the temperature in mirrors of gravitational wave antennae are transformed through the thermal expansion coefficient into additional noise, which leads to the necessity to reexamine the choice of materials for the mirrors.
200 citations
TL;DR: In this article, the mechanical quality factor of a single crystal of silicon vs. temperature was measured at T = 3.5K and a value of 2 × 109 was obtained.
Abstract: Measurements of the mechanical quality factor Q in a single crystal of silicon vs. temperature have been made. A value of 2 × 109 has been measured at T = 3.5K.
138 citations
TL;DR: In this article, the displacement fluctuations of mirrors in optomechanical devices, induced via thermal expansion by temperature fluctuations due either to thermodynamic fluctuations or to fluctuations in the photon absorption, can be made smaller than quantum fluctuations, at the low temperatures, high reflectivities, and high light powers needed to readout displacements at the standard quantum limit.
Abstract: The displacement fluctuations of mirrors in optomechanical devices, induced via thermal expansion by temperature fluctuations due either to thermodynamic fluctuations or to fluctuations in the photon absorption, can be made smaller than quantum fluctuations, at the low temperatures, high reflectivities, and high light powers needed to readout displacements at the standard quantum limit. The result is relevant for the design of quantum-limited gravitational-wave detectors, both ``interferometers'' and ``bars,'' and for experiments to study directly mechanical motion in the quantum regime.
109 citations