Sensitivity below the standard quantum limit in gravitational wave detectors with Michelson-Fabry-Perot readout
- CNISM-Unita di Siena, Dipartimento di Fisica, Universita di Siena, via Roma 56, 53100 Siena (Italy)
- Dipartimento di Fisica, Universita di Firenze, INFN, Sezione di Firenze, and LENS, Via Sansone 1, I-50019 Sesto Fiorentino (Italy)
We calculate the quantum noise limited displacement sensitivity of a Michelson-Fabry-Perot (MFP) interferometer with detuned cavities, followed by phase-sensitive homodyne detection. We show that the standard quantum limit can be surpassed even with resonant cavities and without any signal-recycling mirror nor additional cavities. Indeed, thanks to the homodyne detection, the output field quadrature can be chosen in such a way to cancel the effect of input amplitude fluctuations, i.e., eliminating the force noise. With detuned cavities, the modified opto-mechanical susceptivity allows to reach unlimited sensitivity for large enough (yet finite) optical power. Our expressions include mirror losses and cavity delay effect, for a realistic comparison with experiments. Our study is particularly devoted to gravitational wave detectors and we consider both an interferometer with free-falling mirrors, and a MFP interferometer as readout for a massive detector. In the latter case, the sensitivity curve of the recently conceived ''DUAL'' detector, based on two acoustic modes, is obtained.
- OSTI ID:
- 21211999
- Journal Information:
- Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 12 Vol. 77; ISSN PRVDAQ; ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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