Advanced LIGO

  title={Advanced LIGO},
  author={The Ligo Scientific Collaboration},
The Advanced LIGO gravitational wave detectors are second generation instruments designed and built for the two LIGO observatories in Hanford, WA and Livingston, LA. The two instruments are identical in design, and are specialized versions of a Michelson interferometer with 4 km long arms. As in initial LIGO, Fabry-Perot cavities are used in the arms to increase the interaction time with a gravitational wave, and power recycling is used to increase the effective laser power. Signal recycling… 
Point absorbers in Advanced LIGO.
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 it suggests system wide corrections that can be implemented in current and future GW detectors.
Suppressing parametric instabilities in LIGO using low-noise acoustic mode dampers
Interferometric gravitational-wave detectors like LIGO need to be able to measure changes in their arm lengths of order $10^{-18}~$m or smaller. This requires very high laser power in order to raise
Point Absorber Limits to Future Gravitational-Wave Detectors.
A general approach to the point absorber effect from first principles is presented and the achievable circulating power in current and future gravitational-wave detectors is calculated statistically given different point absorbers configurations.
Angular instability in high optical power suspended cavities.
It is shown that this phenomenon is likely to significantly affect the proposed gravitational wave detectors that require very high optical power, and the power dependent evolution of both the cavity soft and hard mode is observed.
Lightsaber: A Simulator of the Angular Sensing and Control System in LIGO
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
Converting the signal-recycling cavity into an unstable optomechanical filter to enhance the detection bandwidth of gravitational-wave detectors
Current and future interferometeric gravitational-wave detectors are limited predominantly by shot noise at high frequencies. Shot noise is reduced by introducing arm cavities and signal recycling,
Quantum-Enhanced Advanced LIGO Detectors in the Era of Gravitational-Wave Astronomy.
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% and 50% respectively.
Systematic calibration error requirements for gravitational-wave detectors via the Cramér–Rao bound
Gravitational-wave (GW) laser interferometers such as Advanced LIGO (The LIGO Scientific Collaboration 2015 Class. Quantum Grav. 32 074001) transduce spacetime strain into optical power fluctuation.
Pushing cavities to the edge for future gravitational wave detectors
Near-unstable cavities have been proposed as an enabling technology for future gravitational wave detectors, as their compact structure and large beam spot can reduce the thermal noise floor of the