Experimental evidence for an optical spring
- INFN Sezione di Pisa, Pisa (Italy)
- EGO, European Gravitational Observatory, Cascina (Pi) (Italy)
- INFN Sezione di Firenze, Sesto Fiorentino (Italy)
- Universita di Roma 1, and INFN-Roma 1, Roma (Italy)
- Universita di Siena, Siena (Italy)
An optical spring effect has been observed in the motion of a Fabry-Perot cavity suspended in the Low-Frequency Facility, R and D experiment of the VIRGO Collaboration. The experimental setup consists of a 1-cm-long cavity hanging from a mechanical isolation system, conceived to suppress seismic noise transmission to the optical components of the interferometer. The observed radiation pressure effect corresponds to an optical stiffness k{sub opt} ranging between 2.5x10{sup 4} and 6.5x10{sup 4} N/m. This paper reports several measurements of the mirror relative displacement carried out in different working conditions. The measured error signal spectra show broad resonances at frequencies compatible with the optomechanical system. In other runs cavity detuning oscillations have been observed at subhertz frequencies. In these cases the power spectrum of the control loop error signal exhibited a broad resonance with superimposed uniformly spaced peaks. These observations, validated by a simple model, prove that the fluctuations of the optical spring effect can become so large as to exhibit nonlinear features.
- OSTI ID:
- 20852976
- Journal Information:
- Physical Review. A, Journal Name: Physical Review. A Journal Issue: 1 Vol. 74; ISSN 1050-2947; ISSN PLRAAN
- Country of Publication:
- United States
- Language:
- English
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