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Revealing optical loss from modal frequency degeneracy in a long optical cavity.
- Source :
-
Optics express [Opt Express] 2021 Jul 19; Vol. 29 (15), pp. 23902-23915. - Publication Year :
- 2021
-
Abstract
- Optical loss plays a significant role in optical experiments involving optical cavities such as recycling cavities and filter cavities in laser interferometer gravitational-wave detectors. For those cavities, modal frequency degeneracy, where the fundamental and a higher order mode resonate inside the cavity simultaneously, is a potential mechanism which may bring extra optical loss to the cavity thus degrade detection sensitivity. In this paper, we report observation of modal frequency degeneracy in a large-scale suspended Fabry-Pérot cavity. The cavity g-factor is tuned by a CO <subscript>2</subscript> laser heating one test mass, and the cavity finesse is obtained from a ring-down measurement of the transmitted light. We demonstrate that the modal frequency degeneracy can cause a reduction of the cavity finesse by up to ∼30%, corresponding to a ∼2-fold increase in total optical loss. To minimize optical loss in gravitational-wave detectors, the effect of modal frequency degeneracy needs to be taken into account in the design and operation of the detector.
Details
- Language :
- English
- ISSN :
- 1094-4087
- Volume :
- 29
- Issue :
- 15
- Database :
- MEDLINE
- Journal :
- Optics express
- Publication Type :
- Academic Journal
- Accession number :
- 34614646
- Full Text :
- https://doi.org/10.1364/OE.430276