In this section we discuss the main noise sources, which limit the sensitivity of interferometric
gravitational-wave detectors. Fundamentally it should be possible to build systems using laser
interferometry to monitor strains in space, which are limited only by the Heisenberg Uncertainty Principle;
however there are other practical issues, which must be taken into account. Fluctuating gravitational
gradients pose one limitation to the interferometer sensitivity achievable at low frequencies, and
it is the level of noise from this source, which dictates that experiments to look for sub-Hz
gravitational-wave signals have to be carried out in space [291, 275
, 93
, 184
]. In general, for
ground-based detectors the most important limitations to sensitivity result from the effects of seismic
and other ground-borne mechanical noise, thermal noise associated with the test masses and
their suspensions, and quantum noise, which appears at high frequency as shot noise in the
photocurrent from the photodiode, which detects the interference pattern and can appear at low
frequency as radiation pressure noise due to momentum transfer to the test masses from the
photons when using high laser powers. The significance of each of these sources will be briefly
reviewed.
http://www.livingreviews.org/lrr-2011-5 |
Living Rev. Relativity 14, (2011), 5
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