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Liang Liu - One of the best experts on this subject based on the ideXlab platform.
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observation of fundamental Thermal Noise in optical fibers down to infrasonic frequencies
Applied Physics Letters, 2016Co-Authors: Jing Dong, Junchao Huang, Liang LiuAbstract:The intrinsic Thermal Noise in optical fibers represents the ultimate limit for fiber-based systems. However, at infrasonic frequencies, the spectral behavior of the intrinsic Thermal Noise is still unclear. In this letter, we present measurements of the fundamental Thermal Noise in optical fibers that are obtained using a balanced fiber Michelson interferometer. When an ultra-stable laser is used as the laser source and other Noise sources are carefully controlled, the 1/f spectral density of the Thermal Noise is observed down to infrasonic frequencies, and the measured magnitude is consistent with the results of theoretical predictions at frequencies over the range from 0.2 Hz to 20 kHz. Moreover, as observed experimentally, the level of the 1/f Thermal Noise can be reduced by changing the coatings of the optical fibers. This therefore indicates one possible way to reduce Thermal Noise in optical fibers at low Fourier frequencies. Finally, the inconsistency between the experimental data and the existing...
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Observation of Fundamental Thermal Noise in Optical Fibers down to Infrasonic Frequencies
Applied Physics Letters, 2016Co-Authors: Jing Dong, Junchao Huang, Liang LiuAbstract:The intrinsic Thermal Noise in optical fibers is the ultimate limit of fiber-based systems. However, at infrasonic frequencies, the spectral behavior of the intrinsic Thermal Noise remains unclear so far. We present the measurements of the fundamental Thermal Noise in optical fibers obtained using a balanced fiber Michelson interferometer. When an ultra-stable laser is used as the laser source and other Noise sources are carefully controlled, the 1/f spectral density of Thermal Noise is observed down to infrasonic frequencies and the measured magnitude is consistent with the theoretical predictions at the frequencies from 0.2 Hz to 20 kHz. Moreover, as observed in the experiment, the level of 1/f Thermal Noise is reduced by changing the coating of optical fibers. Therefore, a possible way to reduce the Thermal Noise in optical fibers at low Fourier frequencies is indicated. Finally, the inconsistency between the experimental data on thermomechanical Noise and existing theory is discussed.
D. Kondis - One of the best experts on this subject based on the ideXlab platform.
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Thermal Noise modeling for short-channel MOSFETs
IEEE Transactions on Electron Devices, 1996Co-Authors: D.p. Triantis, Alexios Birbas, D. KondisAbstract:An analytical formulation of the Thermal Noise in short-channel MOSFETs, working in the saturation region, is presented. For the Noise calculation, we took into account effects like the field dependent Noise temperature and mobility, the device geometry and the channel length modulation, the back gate effect and the velocity saturation. The derived data from the model are in good agreement with reported Thermal Noise measurements, regarding the Noise bias dependence, for transistors with channel lengths shorter than 1 /spl mu/m. Since the present Thermal Noise models of MOS transistors are valid for channel lengths well above 1 /spl mu/m, the proposed model can be easily incorporated in circuit simulators like SPICE, providing an extension to the analytical Thermal Noise modeling suitable for submicron MOSFETs.
Sergey P. Vyatchanin - One of the best experts on this subject based on the ideXlab platform.
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Thermal Noise of beam splitters in laser gravitational wave detectors
Physical Review D, 2018Co-Authors: Johannes Dickmann, Ronny Nawrodt, Stefanie Kroker, Yuri Levin, Sergey P. VyatchaninAbstract:We present the calculation of Thermal Noise in interferometric gravitational-wave detectors due to the Thermal fluctuations of the beam splitter (BS). This work makes use of a recently developed method of the analysis of Thermal Noise in mirrors from first principles, based on the fluctuation dissipation theorem. The evaluation of BS Thermal Noise is carried out for the two different grav- itational wave observatories, GEO600 and the Advanced Laser Interferometer Gravitational Wave Observatory (aLIGO). The analysis evaluates Thermal Noise from both the substrate and the optical reflective and antireflective stacks located on the BS surface. We demonstrate that the fluctuations of both reflecting and anti-reflecting surfaces significantly contribute to the total Thermal Noise of the BS. The oscillating intensity pattern couples small-scale distortions of the surface to the overall phase readout, and therefore increases the overall Thermal Noise. In the case of aLIGO, the BS contribution is with $0.3\%$ negligibly small. At a frequency of 500Hz, the BS causes about $10\%$ of GEO600's sensitivity limit. BS Noise impairs the feasible sensitivity of the GEO-HF design proposal by about $50\%$.
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Brownian Thermal Noise in functional optical surfaces
Physical Review D, 2017Co-Authors: Stefanie Kroker, D. Heinert, Ronny Nawrodt, Johannes Dickmann, C.b. Rojas Hurtado, Y. Levin, Sergey P. VyatchaninAbstract:We present a formalism to compute Brownian Thermal Noise in functional optical surfaces such as grating reflectors, photonic crystal slabs or complex metamaterials. Such computations are based on a specific readout variable, typically a surface integral of a dielectric interface displacement weighed by a form factor. This paper shows how to relate this form factor to Maxwell's stress tensor computed on all interfaces of the moving surface. As an example, we examine Brownian Thermal Noise in monolithic T-shape grating reflectors. The previous computations by Heinert et al. [Heinert et al., PRD 88 (2013)] utilizing a simplified readout form factor produced estimates of Thermal Noise that are tens of percent higher than those of the exact analysis in the present paper. The relation between the form factor and Maxwell's stress tensor implies a close correlation between the optical properties of functional optical surfaces and Thermal Noise.
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Thermal Noise of folding mirrors
Physical Review D, 2014Co-Authors: D. Heinert, Kieran Craig, Hartmut Grote, Stefan Hild, Harald Lück, Ronny Nawrodt, D. Simakov, Denis V. Vasilyev, Sergey P. Vyatchanin, Holger WittelAbstract:Current gravitational wave detectors rely on the use of Michelson interferometers. One crucial limitation of their sensitivity is the Thermal Noise of their optical components. Thus, for example fluctuational deformations of the mirror surface are probed by a laser beam being reflected from the mirrors at normal incidence. Thermal Noise models are well evolved for that case but mainly restricted to single reflections. In this work we present the effect of two consecutive reflections under a non-normal incidence onto mirror Thermal Noise. This situation is inherent to detectors using a geometrical folding scheme such as GEO\,600. We revise in detail the conventional direct Noise analysis scheme to the situation of non-normal incidence allowing for a modified weighting funtion of mirror fluctuations. An application of these results to the GEO\,600 folding mirror for Brownian, thermoelastic and thermorefractive Noise yields an increase of displacement Noise amplitude by 20\% for most Noise processes. The amplitude of thermoelastic substrate Noise is increased by a factor 4 due to the modified weighting function. Thus the consideration of the correct weighting scheme can drastically alter the Noise predictions and demands special care in any Thermal Noise design process.
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Calculation of Thermal Noise in grating reflectors
Physical Review D, 2013Co-Authors: D. Heinert, Stefan Hild, Ronny Nawrodt, Stefanie Kroker, Daniel Friedrich, Ernst-bernhard Kley, S. Leavey, Iain W. Martin, Andreas Tünnermann, Sergey P. VyatchaninAbstract:Grating reflectors have been repeatedly discussed to improve the Noise performance of metrological applications due to the reduction or absence of any coating material. So far, however, no quantitative estimate on the Thermal Noise of these reflective structures exists. In this work we present a theoretical calculation of a grating reflector’s Noise. We further apply it to a proposed third generation gravitational wave detector. Depending on the grating geometry, the grating material, and the temperature, we obtain a Thermal Noise decrease by up to a factor of 10 compared to conventional dielectric mirrors. Thus the use of grating reflectors can substantially improve the Noise performance in metrological applications.
Jing Dong - One of the best experts on this subject based on the ideXlab platform.
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observation of fundamental Thermal Noise in optical fibers down to infrasonic frequencies
Applied Physics Letters, 2016Co-Authors: Jing Dong, Junchao Huang, Liang LiuAbstract:The intrinsic Thermal Noise in optical fibers represents the ultimate limit for fiber-based systems. However, at infrasonic frequencies, the spectral behavior of the intrinsic Thermal Noise is still unclear. In this letter, we present measurements of the fundamental Thermal Noise in optical fibers that are obtained using a balanced fiber Michelson interferometer. When an ultra-stable laser is used as the laser source and other Noise sources are carefully controlled, the 1/f spectral density of the Thermal Noise is observed down to infrasonic frequencies, and the measured magnitude is consistent with the results of theoretical predictions at frequencies over the range from 0.2 Hz to 20 kHz. Moreover, as observed experimentally, the level of the 1/f Thermal Noise can be reduced by changing the coatings of the optical fibers. This therefore indicates one possible way to reduce Thermal Noise in optical fibers at low Fourier frequencies. Finally, the inconsistency between the experimental data and the existing...
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Observation of Fundamental Thermal Noise in Optical Fibers down to Infrasonic Frequencies
Applied Physics Letters, 2016Co-Authors: Jing Dong, Junchao Huang, Liang LiuAbstract:The intrinsic Thermal Noise in optical fibers is the ultimate limit of fiber-based systems. However, at infrasonic frequencies, the spectral behavior of the intrinsic Thermal Noise remains unclear so far. We present the measurements of the fundamental Thermal Noise in optical fibers obtained using a balanced fiber Michelson interferometer. When an ultra-stable laser is used as the laser source and other Noise sources are carefully controlled, the 1/f spectral density of Thermal Noise is observed down to infrasonic frequencies and the measured magnitude is consistent with the theoretical predictions at the frequencies from 0.2 Hz to 20 kHz. Moreover, as observed in the experiment, the level of 1/f Thermal Noise is reduced by changing the coating of optical fibers. Therefore, a possible way to reduce the Thermal Noise in optical fibers at low Fourier frequencies is indicated. Finally, the inconsistency between the experimental data on thermomechanical Noise and existing theory is discussed.
Nergis Mavalvala - One of the best experts on this subject based on the ideXlab platform.
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Structural Thermal Noise in gram-scale mirror oscillators
New Journal of Physics, 2012Co-Authors: Abraham R. Neben, T. P. Bodiya, Thomas Corbitt, Christopher Wipf, Eric Oelker, Nergis MavalvalaAbstract:The Thermal Noise associated with mechanical dissipation is a ubiquitous limitation to the sensitivity of precision experiments ranging from frequency stabilization to gravitational wave interferometry. We report on the Thermal Noise limits to the performance of 1gm mirror oscillators that are part of a cavity optomechanics experiment to observe quantum radiation pressure Noise. Thermal Noise limits the observed cavity displacement spectrum from 80Hz to 5kHz. We present a calculation of the Thermal Noise, based on finite element analysis of the dissipation due to structural damping, and find it to be in excellent agreement with the experimental result. We conclude with the predicted Thermal Noise for an improved oscillator design, which should be capable of revealing the Noise that arises from quantum backaction in this system.