Optical contamination screening of materials with a high-finesse Fabry-Perot cavity resonated continuously at 106-µm wavelength in vacuum

摘要

An optical-loss measurement system based on a resonant Fabry Perot cavity at 1.06µm in vacuum has been developed for independent monitoring of the cavity total loss and the optical absorption loss. Maintenance of cavity resonance over a one-month period allows the assessment of long-term degradation of the cavity optics in the presence of outgassing materials, with sensitivities of 5 ppm yr for total cavity loss and 2 ppm yr for cavity absorption loss. Test results for light-emitting diodes, Kapton-insulated cable assemblies, and Vac-seal epoxy adhesive are given. Scaling of these results to the optical performance requirements of LIGO is discussed.