Related Experiment Video
Updated: Jun 12, 2026
12:14
The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry
Published on: August 12, 2013
Angular instability due to radiation pressure in the LIGO gravitational-wave detector
Eiichi Hirose1, Keita Kawabe, Daniel Sigg
1Department of Physics, Syracuse University, Syracuse, New York 13244, USA. eiich.hirose@gmail.com
Applied Optics
|June 22, 2010
Summary
Radiation pressure affects the Laser Interferometer Gravitational-Wave Observatory (LIGO) core optics. Feedback control suppresses one angular mode, a finding modeled mathematically for the first time in a complete interferometer.
Area of Science:
- Astrophysics
- Optical Physics
- Gravitational Wave Detection
Background:
- The Laser Interferometer Gravitational-Wave Observatory (LIGO) relies on precise alignment of core optics.
- Radiation pressure, a subtle force, can influence delicate optical systems.
Purpose of the Study:
- To measure the effect of radiation pressure on the angular sensing and control system of LIGO's core optics.
- To develop and validate a mathematical model for this phenomenon within a complete gravitational-wave interferometer.
Main Methods:
- Direct observation of radiation pressure effects on LIGO interferometer core optics at LIGO Hanford Observatory.
- Development of a mathematical model to describe the observed system dynamics.
- Comparison of model predictions with experimental observations.
Main Results:
- The first measurement of radiation pressure's effect on a complete gravitational-wave interferometer's angular control system.
- Demonstration that feedback control suppresses one of the two angular modes when control gain is sufficiently high.
- Successful validation of a mathematical model against observed system dynamics.
Conclusions:
- Radiation pressure is a measurable factor influencing LIGO's angular control system.
- Mathematical modeling provides a robust framework for understanding these optical dynamics.
- The findings contribute to the understanding and optimization of gravitational-wave detector performance.
Related Concept Videos
01:20Momentum And Radiation Pressure
An object absorbing an electromagnetic wave would experience a force in the direction of propagation of the wave. This force occurs because electromagnetic waves contain and transport momentum. The force accounts for the wave's radiation pressure exerted on the object. Maxwell's prediction was confirmed in 1903 by Nichols and Hull by precisely measuring radiation pressures with a torsion balance. The measuring instrument had mirrors suspended from a fiber kept inside a glass container. Nichols...
01:09Radiation Pressure: Problem Solving
The radiation pressure applied by an electromagnetic wave on a perfectly absorbing surface equals the energy density of the wave. The wave's momentum also gets transferred to the surface when an electromagnetic wave is entirely absorbed by it. The rate at which momentum is transmitted to an absorbing surface perpendicular to the propagation direction equals the force on the surface.
The average value of the rate of momentum transfer divided by the absorbing area represents the average force per...
The average value of the rate of momentum transfer divided by the absorbing area represents the average force per...
01:11Atomic Nuclei: Larmor Precession Frequency
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession, and the angular frequency...
01:10Detection of Black Holes
Although black holes were theoretically postulated in the 1920s, they remained outside the domain of observational astronomy until the 1970s.
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
Their closest cousins are neutron stars, which are composed almost entirely of neutrons packed against each other, making them extremely dense. A neutron star has the same mass as the Sun but its diameter is only a few kilometers. Therefore, the escape velocity from their surface is close to the speed of light.
Not until the 1960s, when the first neutron...
01:06Forced Oscillations
When an oscillator is forced with a periodic driving force, the motion may seem chaotic. The motions of such oscillators are known as transients. After the transients die out, the oscillator reaches a steady state, where the motion is periodic, and the displacement is determined.
01:17Sound as Pressure Waves
Sound waves, which are longitudinal waves, can be modeled as the displacement amplitude varying as a function of the spatial and temporal coordinates. As a column of the medium is displaced, its successive columns are also displaced. As the successive displacements differ relatively, a pressure difference with the surrounding pressure is created. The gauge pressure varies across the medium.
The pressure fluctuation depends on the difference in displacements between the successive points in the...
The pressure fluctuation depends on the difference in displacements between the successive points in the...