42 research outputs found
Development of a frequency-detuned interferometer as a prototype experiment for next-generation gravitational-wave detectors
We report on our prototype experiment that uses a 4-m detuned resonant sideband extraction interferometer with suspended mirrors, which has almost the same configuration as the next-generation, gravitational-wave detectors. We have developed a new control scheme and have succeeded in the operation of such an interferometer with suspended mirrors for the first time ever as far as we know. We believe that this is the first such instrument that can see the radiation pressure signal enhancement, which can improve the sensitivity of next-generation gravitational-wave detectors
Diagonalizing sensing matrix of broadband RSE
For a broadband-operated RSE interferometer, a simple and smart length sensing and control scheme was newly proposed. The sensing matrix could be diagonal, owing to a simple allocation of two RF modulations and to a macroscopic displacement of cavity mirrors, which cause a detuning of the RF modulation sidebands. In this article, the idea of the sensing scheme and an optimization of the relevant parameters will be described
Experimental investigation of a control scheme for a tuned resonant sideband extraction interferometer for next-generation gravitational-wave detectors
LCGT plans to use tuned RSE as the optical configuration for its interferometer. A tuned RSE interferometer has five degrees of freedom that need to be controlled in order to operate a gravitational-wave detector, although it is expected to be very challenging because of the complexity of its optical configuration. A new control scheme for a tuned RSE interferometer has been developed and tested with a prototype interferometer to demonstrate successful control of the tuned RSE interferometer. The whole RSE interferometer was successfully locked with the control scheme. Here the control scheme and the current status of the experiment are presented
Experimental investigation of a control scheme for a zero-detuning resonant sideband extraction interferometer for next-generation gravitational-wave detectors
Some next-generation gravitational-wave detectors, such as the American
Advanced LIGO project and the Japanese LCGT project, plan to use power recycled
resonant sideband extraction (RSE) interferometers for their interferometer's
optical configuration. A power recycled zero-detuning (PRZD) RSE
interferometer, which is the default design for LCGT, has five main length
degrees of freedom that need to be controlled in order to operate a
gravitational-wave detector. This task is expected to be very challenging
because of the complexity of optical configuration. A new control scheme for a
PRZD RSE interferometer has been developed and tested with a prototype
interferometer. The PRZD RSE interferometer was successfully locked with the
control scheme. It is the first experimental demonstration of a PRZD RSE
interferometer with suspended test masses. The result serves as an important
step for the operation of LCGT.Comment: 6 pages, 9 figrue
Measurement of optical response of a detuned resonant sideband extraction gravitational wave detector
We report on the optical response of a suspended-mass detuned resonant sideband extraction (RSE) interferometer with power recycling. The purpose of the detuned RSE configuration is to manipulate and optimize the optical response of the interferometer to differential displacements (induced by gravitational waves) as a function of frequency, independently of other parameters of the interferometer. The design of our interferometer results in an optical gain with two peaks: an RSE optical resonance at around 4 kHz and a radiation pressure induced optical spring at around 41 Hz. We have developed a reliable procedure for acquiring lock and establishing the desired optical configuration. In this configuration, we have measured the optical response to differential displacement and found good agreement with predictions at both resonances and all other relevant frequencies. These results build confidence in both the theory and practical implementation of the more complex optical configuration being planned for Advanced LIGO
Direct Observation of Broadband Coating Thermal Noise in a Suspended Interferometer
We have directly observed broadband thermal noise in silica/tantala coatings
in a high-sensitivity Fabry-Perot interferometer. Our result agrees well with
the prediction based on indirect, ring-down measurements of coating mechanical
loss, validating that method as a tool for the development of advanced
interferometric gravitational-wave detectors.Comment: Final version synchronized with publication in Phys. Lett.
Measurement of Optical Response of a Detuned Resonant Sideband Extraction Interferometer
We report on the optical response of a suspended-mass detuned resonant
sideband extraction (RSE) interferometer with power recycling. The purpose of
the detuned RSE configuration is to manipulate and optimize the optical
response of the interferometer to differential displacements (induced by
gravitational waves) as a function of frequency, independently of other
parameters of the interferometer. The design of our interferometer results in
an optical gain with two peaks: an RSE optical resonance at around 4 kHz and a
radiation pressure induced optical spring at around 41 Hz. We have developed a
reliable procedure for acquiring lock and establishing the desired optical
configuration. In this configuration, we have measured the optical response to
differential displacement and found good agreement with predictions at both
resonances and all other relevant frequencies. These results build confidence
in both the theory and practical implementation of the more complex optical
configuration being planned for Advanced LIGO.Comment: 6 pages, 4 figures, for submission to Phys Rev Letter
Sensing and control of the advanced LIGO optical configuration
The LIGO Laboratory 40m prototype interferometer at Caltech is being commissioned to prototype an optical configuration for Advanced LIGO. This optical configuration has to control five length degrees of freedom, and its control topology will be significantly more complicated than any other present interferometers. This paper explains the method of sensing, controls and lock acquisition
The 10m AEI prototype facility A brief overview
The AEI 10 m prototype interferometer facility is currently being constructed
at the Albert Einstein Institute in Hannover, Germany. It aims to perform
experiments for future gravitational wave detectors using advanced techniques.
Seismically isolated benches are planned to be interferometrically
interconnected and stabilized, forming a low-noise testbed inside a 100 m^3
ultra-high vacuum system. A well-stabilized high power laser will perform
differential position readout of 100 g test masses in a 10 m suspended
arm-cavity enhanced Michelson interferometer at the crossover of measurement
(shot) noise and backaction (quantum radiation pressure) noise, the so-called
Standard Quantum Limit (SQL). Such a sensitivity enables experiments in the
highly topical field of macroscopic quantum mechanics. In this article we
introduce the experimental facility and describe the methods employed,
technical details of subsystems will be covered in future papers
Lock Acquisition Scheme For The Advanced LIGO Optical configuration
The lock acquisition scheme for the Advanced LIGO optical configuration, which makes use of "resonant sideband extraction", is under investigation in the 40 meter prototype interferometer at Caltech. The 40m has a similar optical configuration to the one planned for Advanced LIGO which has 5 degrees of freedom for length control. So far we have succeeded in locking the 5 degrees of freedom routinely. The differential mode of arm cavities was locked in the same state as the final setup, and the peak of optical resonance was verified to be around 4 kHz. Currently, since an offset remains in the common mode of the arm cavities, another optical resonance can be seen in common mode optical gain