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  1. Book ; Online: Present and Future of Gravitational Wave Astronomy

    Vajente, Gabriele

    2022  

    Keywords Research & information: general ; Physics ; LIGO ; Virgo ; KAGRA ; gravitational waves ; detector characterization ; data quality ; noise mitigation ; seismic noise ; Newtonian noise ; seismic isolation system ; noise subtraction ; DECIGO ; thermal noise ; quantum noise ; diffraction loss ; interferometers ; ground based gravitational-wave detector ; Advanced Virgo ; gravitational-wave backgrounds ; stochastic gravitational-wave backgrounds ; stochastic searches of gravitational waves ; gravitational-wave laser interferometers ; pulsar timing arrays ; gravitational wave detectors ; optomechanics ; low-noise high-power laser interferometry ; calibration ; interferometer ; gravitational wave ; astrophysics ; laser metrology ; squeezed states ; quantum optics ; gravitational wave detector ; laser interferometer ; cryogenics ; underground ; einstein telescope ; newtonian noise ; coating noise ; silicon ; suspensions ; payload ; cryostat ; core-collapse supernova ; future detectors ; continuous gravitational waves ; neutron stars ; dark matter ; gravitational-wave astrophysics ; stars ; black holes ; stellar evolution ; binary stars ; stellar dynamics ; laser interferometers ; n/a
    Language 0|e
    Size 1 electronic resource (428 pages)
    Publisher MDPI - Multidisciplinary Digital Publishing Institute
    Document type Book ; Online
    Note English ; Open Access
    HBZ-ID HT021620555
    ISBN 9783036552262 ; 303655226X
    Database ZB MED Catalogue: Medicine, Health, Nutrition, Environment, Agriculture

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  2. Article ; Online: Analytical expressions for the clipping of Laguerre- and Hermite-Gauss modes by circular apertures.

    Vajente, Gabriele

    Journal of the Optical Society of America. A, Optics, image science, and vision

    2022  Volume 39, Issue 3, Page(s) 352–357

    Abstract: We present a closed-form analytical expression that describes the effect of clipping by circular apertures on laser beams, described in terms of an expansion in eigenmodes of the paraxial wave equation, in either the Laguerre-Gauss or Hermite-Gauss bases. ...

    Abstract We present a closed-form analytical expression that describes the effect of clipping by circular apertures on laser beams, described in terms of an expansion in eigenmodes of the paraxial wave equation, in either the Laguerre-Gauss or Hermite-Gauss bases. This result provides a faster and more accurate way to compute the coupling between higher-order modes, compared to commonly used grid-based numerical integration.
    Language English
    Publishing date 2022-03-16
    Publishing country United States
    Document type Journal Article
    ZDB-ID 283633-6
    ISSN 1520-8532 ; 1084-7529 ; 0740-3232
    ISSN (online) 1520-8532
    ISSN 1084-7529 ; 0740-3232
    DOI 10.1364/JOSAA.448808
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.B 2689: Show issues Location:
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  3. Article ; Online: In situ correction of mirror surface to reduce round-trip losses in Fabry-Perot cavities.

    Vajente, G

    Applied optics

    2014  Volume 53, Issue 7, Page(s) 1459–1465

    Abstract: High-finesse resonant cavities play an important role in many metrology applications such as gravitational wave detectors. The performance of these cavities can be limited by round-trip losses (RTP) generated by light that is scattered by the mirror ... ...

    Abstract High-finesse resonant cavities play an important role in many metrology applications such as gravitational wave detectors. The performance of these cavities can be limited by round-trip losses (RTP) generated by light that is scattered by the mirror surface defects into higher-order modes that are close to resonance. In this paper we develop a detailed model of this effect and we study possible strategies to correct the mirror surface. We show that it is possible to restrict the correction to the combination of a reduced set of surface deformations that can be reproduced on the mirror using projected heating patterns. We show with an optical simulation that by acting on the cavity mirrors it is possible to reduce RTP to the large angle scattering limit. We also show that the optimal correction can be computed without any a priori knowledge of the mirror surface, but based only on measurements of the power stored inside the cavity, thus opening up the possibility of a simple implementation of the proposed algorithm.
    Language English
    Publishing date 2014-03-01
    Publishing country United States
    Document type Journal Article
    ISSN 1539-4522
    ISSN (online) 1539-4522
    DOI 10.1364/AO.53.001459
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Book ; Online: A Deep Learning Technique to Control the Non-linear Dynamics of a Gravitational-wave Interferometer

    Ma, Peter Xiangyuan / Vajente, Gabriele

    2023  

    Abstract: In this work we developed a deep learning technique that successfully solves a non-linear dynamic control problem. Instead of directly tackling the control problem, we combined methods in probabilistic neural networks and a Kalman-Filter-inspired model ... ...

    Abstract In this work we developed a deep learning technique that successfully solves a non-linear dynamic control problem. Instead of directly tackling the control problem, we combined methods in probabilistic neural networks and a Kalman-Filter-inspired model to build a non-linear state estimator for the system. We then used the estimated states to implement a trivial controller for the now fully observable system. We applied this technique to a crucial non-linear control problem that arises in the operation of the LIGO system, an interferometric gravitational-wave observatory. We demonstrated in simulation that our approach can learn from data to estimate the state of the system, allowing a successful control of the interferometer's mirror . We also developed a computationally efficient model that can run in real time at high sampling rate on a single modern CPU core, one of the key requirements for the implementation of our solution in the LIGO digital control system. We believe these techniques could be used to help tackle similar non-linear control problems in other applications.
    Keywords Computer Science - Machine Learning ; Astrophysics - Instrumentation and Methods for Astrophysics ; General Relativity and Quantum Cosmology
    Subject code 006
    Publishing date 2023-02-15
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Hydrogen-Induced Ultralow Optical Absorption and Mechanical Loss in Amorphous Silicon for Gravitational-Wave Detectors.

    Molina-Ruiz, M / Markosyan, A / Bassiri, R / Fejer, M M / Abernathy, M / Metcalf, T H / Liu, X / Vajente, G / Ananyeva, A / Hellman, F

    Physical review letters

    2024  Volume 131, Issue 25, Page(s) 256902

    Abstract: The sensitivity of gravitational-wave detectors is limited by the mechanical loss associated with the amorphous coatings of the detectors' mirrors. Amorphous silicon has higher refraction index and lower mechanical loss than current high-index coatings, ... ...

    Abstract The sensitivity of gravitational-wave detectors is limited by the mechanical loss associated with the amorphous coatings of the detectors' mirrors. Amorphous silicon has higher refraction index and lower mechanical loss than current high-index coatings, but its optical absorption at the wavelength used for the detectors is at present large. The addition of hydrogen to the amorphous silicon network reduces both optical absorption and mechanical loss for films prepared under a range of conditions at all measured wavelengths and temperatures, with a particularly large effect on films grown at room temperature. The uptake of hydrogen is greatest in the films grown at room temperature, but still below 1.5 at.% H, which show an ultralow optical absorption (below 10 ppm) measured at 2000 nm for 500-nm-thick films. These results show that hydrogenation is a promising strategy to reduce both optical absorption and mechanical loss in amorphous silicon, and may enable fabrication of mirror coatings for gravitational-wave detectors with improved sensitivity.
    Language English
    Publishing date 2024-01-05
    Publishing country United States
    Document type Journal Article
    ZDB-ID 208853-8
    ISSN 1079-7114 ; 0031-9007
    ISSN (online) 1079-7114
    ISSN 0031-9007
    DOI 10.1103/PhysRevLett.131.256902
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Bonn / Germany

    Z 4' 58/153: Show issues

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  6. Article ; Online: Displacement noise from back scattering and specular reflection of input optics in advanced gravitational wave detectors.

    Canuel, B / Genin, E / Vajente, G / Marque, J

    Optics express

    2013  Volume 21, Issue 9, Page(s) 10546–10562

    Abstract: The second generation of ground-based interferometric gravitational wave detectors are currently being built and installed. They are designed to be better in strain sensitivity by about a factor 10 with respect to the first generation. Light originating ... ...

    Abstract The second generation of ground-based interferometric gravitational wave detectors are currently being built and installed. They are designed to be better in strain sensitivity by about a factor 10 with respect to the first generation. Light originating from the laser and following unintended paths, called stray light, has been a major problem during the commissioning of all of the first generation detectors. Indeed, stray light carries information about the phase of the emitting object. Therefore, in the next generation all the optics will be suspended in the vacuum in order to mitigate their associated stray light displacement noise. Despite this additional precaution, the challenging target sensitivity at low frequency which is partially limited by quantum radiation pressure combined with up-conversion effects, requires more detailed investigation. In this paper, we turn our attention to stray light originating from auxiliary optical benches. We use a dedicated formalism to compute the re-coupling of back-reflected and back-scattered light. We show, in particular, how much care should be taken in designing and setting requirements for the input bench optics.
    MeSH term(s) Accelerometry/instrumentation ; Artifacts ; Computer Simulation ; Computer-Aided Design ; Equipment Design ; Equipment Failure Analysis ; Gravitation ; Interferometry/instrumentation ; Lasers ; Light ; Models, Theoretical ; Scattering, Radiation
    Language English
    Publishing date 2013-05-06
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/OE.21.010546
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: A high throughput instrument to measure mechanical losses in thin film coatings.

    Vajente, G / Ananyeva, A / Billingsley, G / Gustafson, E / Heptonstall, A / Sanchez, E / Torrie, C

    The Review of scientific instruments

    2017  Volume 88, Issue 7, Page(s) 73901

    Abstract: Brownian thermal noise generated by mechanical losses in thin film coatings limits the sensitivity of gravitational wave detectors, as well as several high precision metrology experiments. Improving the sensitivity of the next generation of gravitational ...

    Abstract Brownian thermal noise generated by mechanical losses in thin film coatings limits the sensitivity of gravitational wave detectors, as well as several high precision metrology experiments. Improving the sensitivity of the next generation of gravitational wave detectors will require optical coatings with significantly reduced mechanical losses. In this paper, we describe a system that we developed to measure the mechanical loss angle of thin film coatings deposited on fused silica substrates. The novelty of this system resides in the capability of parallel measurement of up to four samples and the ability to simultaneously probe all the resonant modes of each sample. This high throughput measurement system allows the exploration of a large number of deposition and material parameters, which can be tuned to achieve low loss coatings.
    Language English
    Publishing date 2017-07
    Publishing country United States
    Document type Journal Article
    ZDB-ID 209865-9
    ISSN 1089-7623 ; 0034-6748
    ISSN (online) 1089-7623
    ISSN 0034-6748
    DOI 10.1063/1.4990036
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Accelerated convergence method for fast Fourier transform simulation of coupled cavities.

    Day, R A / Vajente, G / Pichot du Mezeray, M

    Journal of the Optical Society of America. A, Optics, image science, and vision

    2014  Volume 31, Issue 3, Page(s) 652–660

    Abstract: Fast Fourier transform (FFT) simulation was used to calculate the power and spatial distribution of resonant fields in optical cavities. This is an important tool when characterizing the effect of imperfect geometry and mirror aberrations. This method is, ...

    Abstract Fast Fourier transform (FFT) simulation was used to calculate the power and spatial distribution of resonant fields in optical cavities. This is an important tool when characterizing the effect of imperfect geometry and mirror aberrations. This method is, however, intrinsically slow when the cavities are of relatively high finesse. When this is the case, an accelerated convergence scheme may be used to calculate the steady-state cavity field with a speed that is orders of magnitude faster. The rate of convergence of this method, however, is unpredictable, as many different factors may detrimentally affect its performance. In addition, its use in multiple cavity configurations is not well understood. An in-depth study of the limitations and optimization of this method is presented, together with a formulation of its use in multiple cavity configurations. This work has not only resulted in consistent improvement in performance and stability of the accelerated convergence method but also allows the simulation of optical configurations, which would not previously have been possible.
    Language English
    Publishing date 2014-03-01
    Publishing country United States
    Document type Journal Article
    ZDB-ID 283633-6
    ISSN 1520-8532 ; 1084-7529 ; 0740-3232
    ISSN (online) 1520-8532
    ISSN 1084-7529 ; 0740-3232
    DOI 10.1364/JOSAA.31.000652
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

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  9. Book ; Online: Comprehensive study of amorphous metal oxide and Ta$_2$O$_5$-based mixed oxide coatings for gravitational-wave detectors

    Fazio, Mariana A. / Vajente, Gabriele / Yang, Le / Ananyeva, Alena / Menoni, Carmen S.

    2021  

    Abstract: High finesse optical cavities of current interferometric gravitational-wave detectors are significantly limited in sensitivity by laser quantum noise and coating thermal noise. The thermal noise is associated with internal energy dissipation in the ... ...

    Abstract High finesse optical cavities of current interferometric gravitational-wave detectors are significantly limited in sensitivity by laser quantum noise and coating thermal noise. The thermal noise is associated with internal energy dissipation in the materials that compose the test masses of the interferometer. Our understanding of how the internal friction is linked to the amorphous material structure is limited due to the complexity of the problem and the lack of studies that span over a large range of materials. We present a systematic investigation of amorphous metal oxide and Ta$_2$O$_5$-based mixed oxide coatings to evaluate their suitability for low Brownian noise experiments. It is shown that the mechanical loss of metal oxides is correlated to their amorphous morphology, with continuous random network materials such as SiO$_2$ and GeO$_2$ featuring the lowest loss angles. We evaluated different Ta$_2$O$_5$-based mixed oxide thin films and studied the influence of the dopant in the optical and elastic properties of the coating. We estimated the thermal noise associated with high-reflectance multilayer stacks that employ each of the mixed oxides as the high index material. We concluded that the current high index material of TiO$_2$-doped Ta$_2$O$_5$ is the optimal choice for reduced thermal noise among Ta$_2$O$_5$-based mixed oxide coatings with low dopant concentrations.
    Keywords Condensed Matter - Materials Science ; Physics - Applied Physics ; Physics - Instrumentation and Detectors
    Subject code 620
    Publishing date 2021-08-04
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Modifications of ion beam sputtered tantala thin films by secondary argon and oxygen bombardment.

    Yang, Le / Randel, Emmett / Vajente, Gabriele / Ananyeva, Alena / Gustafson, Eric / Markosyan, Ashot / Bassiri, Riccardo / Fejer, Martin / Menoni, Carmen

    Applied optics

    2020  Volume 59, Issue 5, Page(s) A150–A154

    Abstract: Amorphous tantala ( ...

    Abstract Amorphous tantala (
    Language English
    Publishing date 2020-03-26
    Publishing country United States
    Document type Journal Article
    ISSN 1539-4522
    ISSN (online) 1539-4522
    DOI 10.1364/AO.59.00A150
    Database MEDical Literature Analysis and Retrieval System OnLINE

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