Thermal Loading and Modal Frequency Degeneracy in Optical Resonators for the Laser Interferometer Gravitational-wave Observatory (LIGO).
ProQuest, 2009 - 115 pages
A Fabry-Perot ring cavity known as a modecleaner uses calibrated absorption loss to measure the effects of high circulating power similar to what will be observed in resonant systems for Advanced LIGO. An additional modecleaner with low absorption loss is also tested. Results show that power coupling from the fundamental mode to frequency-degenerate higher-order modes significantly degrades the resonant fundamental mode necessary for gravitational-wave detection. Models of thermal distortion including thermal lensing and thermoelastic surface deformation are used to simulate the behavior of various resonant interferometer configurations. Comparisons between modal frequency degeneracy data and simulations are found to be in reasonable agreement, allowing degeneracy predictions for LIGO resonators most susceptible to thermal loading. Finally, mitigation of thermal effects is discussed, as well as solutions for designing interferometers utilizing power levels greater than those of Advanced LIGO.
What people are saying - Write a review
We haven't found any reviews in the usual places.
Simulation of laserinduced thermal distortions
Thermal loading experiment
Predictions for future LIGO resonators
an interferometer simulation program
Mirror and beamspitter diagram
absorbing modecleaner absorption loss Advanced LIGO arm amplitude arm-cavity astigmatic beam waist beamsplitter calcium fluoride calculated cavity length cavity's coating absorption configuration curved mirror degenerate higher-order modes degenerate modes detection eigenmode Enhanced and Advanced Enhanced LIGO error signal filtering finesse four-mirror frequency-degenerate higher-order modes frequency-degenerate modes fundamental mode fundamental-mode power fused silica g-factor product Gaussian beam gravitational waves gravitational-wave detectors Hello and Vinet incident power increases initial LIGO input power interferometer intracavity kW of circulating laser laser power LIGO arm cavity LIGO suspended modecleaner LIGO's lineshape locked to resonance low-loss modecleaner maximum Melody modal frequency degeneracy mode analyzer mode-matching mW of absorbed optical resonator power recycling cavity radii of curvature radius radius of curvature resonance frequency s-polarized Semi-Infinite Optic shows sideband mode simulations skewed sorbed substrate table-top modecleaner test masses thermal distortion thermal expansion thermal lensing thermal loading experiment thermoelastic deformation threshold transmission transmitted power