ORCID Profile
0000-0002-5577-2273
Current Organisation
Leibniz Universität Hannover
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Astronomical and Space Sciences not elsewhere classified | Astronomical and Space Sciences | Quantum Physics | Quantum Optics | Quantum Information, Computation and Communication | Lasers and Quantum Electronics | General Relativity and Gravitational Waves | Astronomical and Space Instrumentation
Expanding Knowledge in the Physical Sciences | Expanding Knowledge in the Information and Computing Sciences | Expanding Knowledge in Technology |
Publisher: IOP Publishing
Date: 19-03-2002
Publisher: American Physical Society (APS)
Date: 12-05-2005
Publisher: American Physical Society (APS)
Date: 30-04-2004
Publisher: American Astronomical Society
Date: 18-12-2017
Publisher: Springer Science and Business Media LLC
Date: 16-10-2017
DOI: 10.1038/NATURE24471
Abstract: On 17 August 2017, the Advanced LIGO and Virgo detectors observed the gravitational-wave event GW170817-a strong signal from the merger of a binary neutron-star system. Less than two seconds after the merger, a γ-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO-Virgo-derived location of the gravitational-wave source. This sky region was subsequently observed by optical astronomy facilities, resulting in the identification of an optical transient signal within about ten arcseconds of the galaxy NGC 4993. This detection of GW170817 in both gravitational waves and electromagnetic waves represents the first 'multi-messenger' astronomical observation. Such observations enable GW170817 to be used as a 'standard siren' (meaning that the absolute distance to the source can be determined directly from the gravitational-wave measurements) to measure the Hubble constant. This quantity represents the local expansion rate of the Universe, sets the overall scale of the Universe and is of fundamental importance to cosmology. Here we report a measurement of the Hubble constant that combines the distance to the source inferred purely from the gravitational-wave signal with the recession velocity inferred from measurements of the redshift using the electromagnetic data. In contrast to previous measurements, ours does not require the use of a cosmic 'distance ladder': the gravitational-wave analysis can be used to estimate the luminosity distance out to cosmological scales directly, without the use of intermediate astronomical distance measurements. We determine the Hubble constant to be about 70 kilometres per second per megaparsec. This value is consistent with existing measurements, while being completely independent of them. Additional standard siren measurements from future gravitational-wave sources will enable the Hubble constant to be constrained to high precision.
Publisher: American Physical Society (APS)
Date: 12-08-2005
Publisher: Optica Publishing Group
Date: 10-02-2021
DOI: 10.1364/OE.416713
Abstract: In this article, we present a novel spectroscopy technique that improves the signal-to-shot-noise ratio without the need to increase the laser power. Detrimental effects by technical noise sources are avoided by frequency-modulation techniques (frequency up-shifting). Superimposing the signal on non-classical states of light leads to a reduced quantum noise floor. Our method reveals in a proof-of-concept experiment small signals at Hz to kHz frequencies even below the shot noise limit. Our theoretical calculations fully support our experimental findings. The proposed technique is interesting for applications such as high-precision cavity spectroscopy, e.g., for explosive trace gas detection where the specific gas might set an upper limit for the laser power employed.
Publisher: American Physical Society (APS)
Date: 28-09-2022
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 03-2015
Publisher: IOP Publishing
Date: 11-08-2003
Publisher: American Physical Society (APS)
Date: 30-10-2014
Publisher: The Optical Society
Date: 15-06-2015
DOI: 10.1364/OE.23.016517
Publisher: IOP Publishing
Date: 02-03-2006
Publisher: IOP Publishing
Date: 29-09-2004
Publisher: American Astronomical Society
Date: 16-10-2017
Publisher: IOP Publishing
Date: 21-04-2005
Publisher: AIP
Date: 2009
DOI: 10.1063/1.3131331
Publisher: IEEE
Date: 05-2007
Publisher: OSA
Date: 2015
Publisher: Elsevier BV
Date: 2021
Publisher: IOP Publishing
Date: 12-03-2002
Publisher: SPIE
Date: 21-02-2003
DOI: 10.1117/12.459095
Publisher: Elsevier BV
Date: 2004
Publisher: The Royal Society
Date: 16-04-2018
Abstract: Interferometric gravitational wave detectors (such as advanced LIGO) employ high-power solid-state lasers to maximize their detection sensitivity and hence their reach into the universe. These sophisticated light sources are ultra-stabilized with regard to output power, emission frequency and beam geometry this is crucial to obtain low detector noise. However, even when all laser noise is reduced as far as technically possible, unavoidable quantum noise of the laser still remains. This is a consequence of the Heisenberg Uncertainty Principle, the basis of quantum mechanics: in this case, it is fundamentally impossible to simultaneously reduce both the phase noise and the litude noise of a laser to arbitrarily low levels. This fact manifests in the detector noise budget as two distinct noise sources—photon shot noise and quantum radiation pressure noise—which together form a lower boundary for current-day gravitational wave detector sensitivities, the standard quantum limit of interferometry. To overcome this limit, various techniques are being proposed, among them different uses of non-classical light and alternative interferometer topologies. This article explains how quantum noise enters and manifests in an interferometric gravitational wave detector, and gives an overview of some of the schemes proposed to overcome this seemingly fundamental limitation, all aimed at the goal of higher gravitational wave event detection rates. This article is part of a discussion meeting issue ‘The promises of gravitational-wave astronomy’.
Publisher: American Physical Society (APS)
Date: 28-11-2005
Publisher: American Physical Society (APS)
Date: 08-09-2005
Publisher: IOP Publishing
Date: 29-03-2006
Publisher: AIP Publishing
Date: 23-07-2003
DOI: 10.1063/1.1589160
Abstract: The British–German interferometric gravitational-wave detector GEO600 uses two high-finesse triangular ring cavities of 8 m optical pathlength each, as an optical mode-cleaning system. The modecleaner system is housed in an ultrahigh-vacuum environment to avoid contamination of the optics and to minimize both the influence of refractive index variations of the air and acoustic coupling to the optics. To isolate the cavities from seismic noise, all optical components are suspended as double pendulums. These pendulums are d ed at their resonance frequencies at the upper pendulum stage with magnet-coil actuators. A suspended reaction mass supports three coils matching magnets bonded onto the surface of one mirror of each cavity, allowing length control of the modecleaner cavities to maintain resonance with the laser light. A fully automated control system stabilizes the frequency of the slave laser to that of the master laser, the frequency of the master laser to the length of the first modecleaner and the length of the first to the length of the second modecleaner. The control system uses the Pound–Drever–Hall sideband technique and operates autonomously over long time periods with only infrequent human interaction. The duty cycle of the system was measured to be 99.7% during an 18 day period. The throughput of the whole modecleaner system is about 50%. In this article, we give an overview of the mechanical and optical setup and the achieved performance of the double modecleaner system.
Publisher: IEEE
Date: 10-2012
Publisher: Wiley
Date: 04-10-2016
Publisher: American Physical Society (APS)
Date: 14-07-2022
Publisher: American Physical Society (APS)
Date: 05-01-2007
Publisher: American Physical Society (APS)
Date: 07-05-2004
Publisher: American Astronomical Society
Date: 07-04-2017
Publisher: American Physical Society (APS)
Date: 10-03-2008
Publisher: American Physical Society (APS)
Date: 10-03-2008
Publisher: American Physical Society (APS)
Date: 06-2004
Publisher: Elsevier BV
Date: 04-2023
Publisher: American Physical Society (APS)
Date: 10-03-2008
Publisher: American Physical Society (APS)
Date: 10-03-2008
Publisher: Springer Science and Business Media LLC
Date: 26-04-2018
DOI: 10.1007/S41114-018-0012-9
Abstract: We present possible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron star systems, which are the most promising targets for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and $$90\\%$$ 90 % credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5– $$20~\\mathrm {deg}^2$$ 20 deg 2 requires at least three detectors of sensitivity within a factor of $$\\sim 2$$ ∼ 2 of each other and with a broad frequency bandwidth. When all detectors, including KAGRA and the third LIGO detector in India, reach design sensitivity, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.
Publisher: American Physical Society (APS)
Date: 25-03-2010
Publisher: Optica Publishing Group
Date: 03-04-2022
DOI: 10.1364/OE.465186
Abstract: We present a novel method to fully estimate Gaussian bipartite polarization states using only a single homodyne detector. Our approach is based on [ Phys. Rev. Lett. 102 , 020502 ( 2009 ) 10.1103/PhysRevLett.102.020502 ], but circumvents additional optics, and thereby losses, in the signal path. We provide an intuitive explanation of our scheme without needing to define auxiliary modes. With six independent measurements, we fully reconstruct the state’s covariance matrix. We validate our method by comparing it to a conventional dual-homodyne measurement scheme.
Publisher: American Physical Society (APS)
Date: 13-01-2016
Publisher: IOP Publishing
Date: 12-04-2017
Publisher: American Physical Society (APS)
Date: 25-10-2005
Publisher: American Physical Society (APS)
Date: 25-10-2005
Publisher: IOP Publishing
Date: 24-10-2007
Publisher: American Astronomical Society
Date: 20-04-2007
DOI: 10.1086/511329
Publisher: American Physical Society (APS)
Date: 28-05-2014
Publisher: IEEE
Date: 06-2007
Publisher: American Physical Society (APS)
Date: 02-06-2004
Publisher: IOP Publishing
Date: 09-02-2004
Publisher: Springer Science and Business Media LLC
Date: 14-07-2006
Publisher: IOP Publishing
Date: 03-02-2004
Publisher: American Physical Society (APS)
Date: 07-03-2006
Publisher: American Physical Society (APS)
Date: 23-12-2009
Publisher: IOP Publishing
Date: 07-08-2003
Publisher: IOP Publishing
Date: 24-03-2006
Publisher: World Scientific Publishing Company
Date: 02-2006
Publisher: Optica Publishing Group
Date: 11-08-2009
DOI: 10.1364/OL.34.002465
Abstract: We report on the successful implementation of an approach to locking the frequencies of an optical parametric oscillator (OPO)-based squeezed-vacuum source and its driving laser. The technique allows the simultaneous measurement of the phase shifts induced by a cavity, which may be used for the purposes of frequency locking, as well as the simultaneous measurement of the sub-quantum-noise-limited (sub-QNL) phase quadrature output of the OPO. The homodyne locking technique is cheap, easy to implement, and has the distinct advantage that subsequent homodyne measurements are automatically phase locked. The homodyne locking technique is also unique in that it is a sub-QNL frequency discriminator.
Publisher: IEEE
Date: 05-2007
Publisher: American Physical Society (APS)
Date: 30-07-2007
Publisher: Optica Publishing Group
Date: 07-2006
DOI: 10.1364/OL.31.002000
Abstract: We present results on the power stabilization of a Nd:YAG laser in the frequency band from 1 Hz to 100 kHz. High-power, low-noise photodetectors are used in a dc-coupled control loop to achieve relative power fluctuations down to 5 x 10(-9) Hz(-1/2) at 10 Hz and 3.5 x 10(-9) Hz(-1/2) up to several kHz, which is very close to the shot-noise limit for 80 mA of detected photocurrent on each detector. We investigated and eliminated several noise sources such as ground loops and beam pointing. The achieved stability level is close to the requirements for the Advanced LIGO gravitational wave detector.
Publisher: Optica Publishing Group
Date: 15-09-2004
DOI: 10.1364/OL.29.002148
Abstract: We show that frequency and intensity noise in a Nd:YAG laser are correlated to a high degree and can be traced to the same underlying cause, namely, power fluctuations of the pump source. Because of this correlation, simultaneous suppression of frequency and intensity noise by 30 dB is achieved by means of a single actuator, the pump power.
Location: Australia
Start Date: 08-2022
End Date: 08-2025
Amount: $531,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 04-2017
End Date: 03-2024
Amount: $31,300,000.00
Funder: Australian Research Council
View Funded Activity