Modal frequency degeneracy in thermally loaded optical resonators

Authors

Amber L. Bullington, Brian T. Lantz, Martin M. Fejer, and Robert L. Byer

Abstract

We observe power coupling from the fundamental mode to frequency-degenerate higher-order spatial modes in optical resonators illuminated with a 30 W laser. Thermally-induced modal frequency degeneracy facilitates power transfer from the fundamental mode to higher-order modes, reduces power coupling into the cavity, and triggers power fluctuations. Modeling thermoelastic deformation of a mirror’s surface shows predicted modal frequency degeneracy to be in reasonable agreement with experimental observations. Predictions for the Laser Interferometer Gravitational-wave Observatory (LIGO) show that the circulating fundamental-mode power necessary for gravitational-wave detection is compromised at coating absorptions of 3.8 and 0:44 ppm for Enhanced and Advanced LIGO Fabry–Pérot cavities, respectively.

Journal

Applied Optics

Volume

47

Number

15

Date

05/2008
AttachmentSize
Bullington AO20082.48 MB