LIGO Document P990003-x0

Quantum Limited Optical Phase Detection in a High Power Suspended Interferometer

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P - Publications
The LIGO Project (Laser Interferometer Gravitational-Wave Observatory) is currently engages in the construction of a new observatory to measure gravitational radiation from astrophysical sources. The first generation of interferometric gravitational wave antennas is scheduled to come on-line in 2001. With an initial noise level of 3 x 10-23 strain/Hz at frequencies around 200 Hz, these antennas represent the most sensitive instruments ever constructed for the detection of gravitational radiation. To achieve the required sensitivity, the antennas are configured as recycled Michelson Interferometers with Fabry-Perot cavities in the Michelson arms.

One of the fundamental limits associated with an instrument of this type is the ability to detect differential phase shifts between the beams returning to the beamsplitter from the Fabry-Perot arm cavities. To achieve the planned sensitivity to gravitational radiation, this detection should be limited only by photon counting statistics (“shot noise”) at a level of 8 x 10-11 radians/Hz between 150 Hz and 10 kHz.

The goal of this work is to develop and demonstrate the techniques which are necessary to achieve this optical phase sensitivity. A prototype recycled Michelson interferometer was constructed which reached an optical phase sensitivity of 12 x 10-11 radians/Hz above 600 Hz.

This thesis describes the methods used to achieve this optical phase sensitivity, and details the lessons learned from operating the prototype instrument. We pay particular attention to interferometric control of suspended optics, laser frequency control, and thermal lensing.

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Migrated document information from the old DCC:
- Full document number: LIGO-P990003-00-R
- Author(s): Brian Lantz
- Document date: 1999-02-01
- Document received date: 1999-02-26
- Document entry date: 1999-02-26
- Publcation info: PhD Thesis, MIT (1999)
- Publication author(s): Lantz, B.

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