Observation of optical torsional stiffness in a high optical power cavity

Fan, Y.; Merrill, L.; Zhao, C.; Li, Ju; Blair, David; Slagmolen, B. J. J.; Hosken, David J.; Brooks, A. F.; Veitch, P. J.; Mudge, D.; Münch, J.

doi:10.1063/1.3088850

Cited by 7 publications

(7 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We measured the negative torsional optical spring constant k op for the ITM yaw mode as a function of the cavity g-factor in the 80 m suspended cavity at HOPF. 24 The experimental results prove the Sidles-Sigg theory. Most recently, Hirose et al 25 studied this effect on the initial LIGO.…”

Section: Sidles-sigg Instabilitymentioning

confidence: 54%

Controlling Instabilities in High Optical Power Interferometers

Fang

Zhao

et al. 2011

Int. J. Mod. Phys. D

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Sidles-sigg Instabilitymentioning

confidence: 54%

Controlling Instabilities in High Optical Power Interferometers

Fang

Zhao

et al. 2011

Int. J. Mod. Phys. D

Self Cite

View full text Add to dashboard Cite

show abstract

“…The theory of the RP's effect on angular mechanical transfer functions (tfs) was not completely modeled until 2006 and presented in the paper by Sidles and Sigg [8]. More elaboration of this topic can also be found in [9][10][11]. The concern arose that RP might be a factor limiting LIGO's ability to increase the light power inside the arm cavities.…”

Section: Introductionmentioning

confidence: 99%

Lightsaber: A Simulator of the Angular Sensing and Control System in LIGO

Andríc

Harms

2021

Galaxies

View full text Add to dashboard Cite

The suspended test masses of gravitational-wave (GW) detectors require precise alignment to be able to operate the detector stably and with high sensitivity. This includes the continuous counter-acting of seismic disturbances, which, below a few Hertz, are not sufficiently reduced by the seismic isolation system. The residual angular motion of suspended test masses is further suppressed by the Angular Sensing and Control (ASC) system. However, in doing so, the angular motion can be enhanced by the ASC at higher frequencies where the seismic isolation system is very effective. This has led to sensitivity limitations between about 10 Hz and 25 Hz of the LIGO detectors in past observation runs. The observed ASC noise was larger than simple models predict, which means that more accurate detector models and new simulation tools are required. In this article, we present Lightsaber, a new time-domain simulator of the ASC in LIGO. Lightsaber is a nonlinear simulation of the optomechanical system consisting of the high-power cavity laser beam and the last two stages of suspension in LIGO including the ASC. The main noise inputs are power fluctuations of the laser beam at the input of the arm cavities, read-out noise of sensors used for the ASC, displacement noise from the suspension platforms, and noise introduced by the suspension damping loops. While the plant simulation uses local degrees of freedom of individual suspension systems, the control is applied on a global angular basis, which requires a conversion between the local and global bases for sensing and actuation. Some of the studies that can be done with this simulation concern mis-centering of the beam-spot (BS) position on the test masses, the role of laser power fluctuations for angular dynamics, and the role of the various nonlinear dynamics. The next important step following this work will be a detailed comparison between Lightsaber results and data from the control channels of the LIGO detectors.

show abstract

“…By 2003, it was clear in the LIGO community that the effect of radiation pressure on angular dynamics was relevant for LIGO [21] and the full details of the effects were described by Sidles and Sigg in 2006 [20]. Fan et al measured the predicted optical-mechanical torsional stiffness at the Gingin Facility in Australia [10], Driggers et. al.…”

Section: Introductionmentioning

confidence: 99%

Angular control of optical cavities in a radiation-pressure-dominated regime: the Enhanced LIGO case

et al. 2013

View full text Add to dashboard Cite

We describe the angular sensing and control (ASC) of 4 km detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO). Enhanced LIGO, the culmination of the first generation LIGO detectors, operated between 2009 and 2010 with about 40 kW of laser power in the arm cavities. In this regime, radiation-pressure effects are significant and induce instabilities in the angular opto-mechanical transfer functions. Here we present and motivate the ASC design in this extreme case and present the results of its implementation in Enhanced LIGO. Highlights of the ASC performance are successful control of opto-mechanical torsional modes, relative mirror motions of ≤ 1 × 10 −7 rad rms, and limited impact on in-band strain sensitivity.

show abstract

Observation of optical torsional stiffness in a high optical power cavity

Abstract: Observation of optical torsional stiffness in a high optical power cavity, Applied Physics Letters, 2009; 94(8):p081105, 3p.

Cited by 7 publications

References 12 publications

Controlling Instabilities in High Optical Power Interferometers

Controlling Instabilities in High Optical Power Interferometers

Lightsaber: A Simulator of the Angular Sensing and Control System in LIGO

Angular control of optical cavities in a radiation-pressure-dominated regime: the Enhanced LIGO case

Contact Info

Product

Resources

About