Direct measurement of absorption-induced wavefront distortion in high optical power systems

Brooks, A. F.; Hosken, David J.; Münch, J.; Veitch, P. J.; Yan, Z.; Zhao, C.; Fan, Y.; Li, Ju; Blair, David; Willems, P. A.; Slagmolen, B. J. J.; Degallaix, J.

doi:10.1364/ao.48.000355

Cited by 16 publications

(9 citation statements)

References 23 publications

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“…We note that to achieve the same reduction in shot noise would require 85% (L1) and 65% (H1) more laser power, which is beyond the capability of the current laser system. Moreover, increasing the laser power complicates the control of the interferometer due to thermal effects [21], angular instabilities caused by photon radiation-pressure induced torques [22], and parametric instabilities [23].…”

Section: Resultsmentioning

confidence: 99%

Quantum-Enhanced Advanced LIGO Detectors in the Era of Gravitational-Wave Astronomy

Tse¹,

Yu²,

Kijbunchoo³

et al. 2019

Phys. Rev. Lett.

504

323

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The Laser Interferometer Gravitational Wave Observatory (LIGO) has been directly detecting gravitational waves from compact binary mergers since 2015. We report on the first use of squeezed vacuum states in the direct measurement of gravitational waves with the Advanced LIGO H1 and L1 detectors. This achievement is the culmination of decades of research to implement squeezed states in gravitational-wave detectors. During the ongoing O3 observation run, squeezed states are improving the sensitivity of the LIGO interferometers to signals above 50 Hz by up to 3 dB, thereby increasing the expected detection rate by 40% (H1) and 50% (L1).

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Section: Resultsmentioning

confidence: 99%

Quantum-Enhanced Advanced LIGO Detectors in the Era of Gravitational-Wave Astronomy

Tse¹,

Yu²,

Kijbunchoo³

et al. 2019

Phys. Rev. Lett.

504

323

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“…Equation ( 9) from Vajente calculates the fundamental mode amplitude inside an optical cavity that includes resonant scattering to a HOM. From that equation, the manuscript then determines the additional loss term from the resonant scattering to a HOM in Equation (11) in that manuscript. Unfortunately, that manuscript contains a minor typographical error in the printed version of Equation ( 11) which does not affect its conclusions.…”

Section: Scattering Into Non-resonant and Partially Resonant Higher Order Modesmentioning

confidence: 99%

“…A salient example is a point-like absorber (a "point absorber"): a sub-millimeter scale, highly absorbing region on the surface of the test mass. Within aLIGO, Hartmann wavefront sensors (HWS) [10,11] measure the spatial distribution of the integrated thermo-refractive and thermo-elastic deformations in the main LIGO optics induced by operation at high power. Measurements performed in-situ have detected unambiguous evidence of point absorbers on at least 5 of 8 observed test masses [12].…”

Section: Introductionmentioning

confidence: 99%

Point absorbers in Advanced LIGO

et al. 2021

Self Cite

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Small, highly absorbing points are randomly present on the surfaces of the main interferometer optics in Advanced LIGO. The resulting nano-meter scale thermo-elastic deformations and substrate lenses from these micron-scale absorbers significantly reduces the sensitivity of the interferometer directly though a reduction in the power-recycling gain and indirect interactions with the feedback control system. We review the expected surface deformation from point absorbers and provide a pedagogical description of the impact on power build-up in second generation gravitational wave detectors (dual-recycled Fabry-Perot Michelson interferometers). This analysis predicts that the power-dependent reduction in interferometer performance will significantly degrade maximum stored power by up to 50% and hence, limit GW sensitivity, but suggests system wide corrections that can be implemented in current and future GW detectors. This is particularly pressing given that future GW detectors call for an order of magnitude more stored power than currently used in Advanced LIGO in Observing Run 3. We briefly review strategies to mitigate the effects of point absorbers in current and future GW wave detectors to maximize the success of these enterprises.

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“…Given the fact that thermal lensing and absorption are strongly related, a standard method to determine a material's absorption is to measure its thermal lens [2][3][4]. In literature, there are several known methods to measure thermal lensing: Measuring the change in the radius of curvature with a Shack-Hartmann wave-front sensor [5,6]; measuring the beam size change either with a high dynamic range CCD camera or using a combination of an iris aperture and a photo diode [2,3,[7][8][9]. A third method is the expansion of the beam into cavity eigenmodes [10].…”

Section: Introductionmentioning

confidence: 99%

Novel technique for thermal lens measurement in commonly used optical components

Bogan¹,

Kwee²,

Hild³

et al. 2015

Opt. Express

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The absorption of light in transmissive optics cause a thermally induced effect known as thermal lensing. This effect provokes an often undesired change of a laser beam transmitted by the optic. In this paper we present a measurement method that allows us to determine thermal lensing in commonly used optical components. The beam influenced by the thermal lens is expanded into the eigenmodes of an optical cavity, and its modal content is analyzed in the eigenbasis of the cavity. The measured quantity depends neither on beam parameters nor on the position of the optical component under investigation. This method allows, to our knowledge, for the first time the direct measurement of the mode conversion coefficient |ε(2)| of the thermal lens.

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Direct measurement of absorption-induced wavefront distortion in high optical power systems

Cited by 16 publications

References 23 publications

Quantum-Enhanced Advanced LIGO Detectors in the Era of Gravitational-Wave Astronomy

Quantum-Enhanced Advanced LIGO Detectors in the Era of Gravitational-Wave Astronomy

Point absorbers in Advanced LIGO

Novel technique for thermal lens measurement in commonly used optical components

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