Precision interferometry in a new shape: higher-order Laguerre-Gauss modes for gravitational wave detection

[摘要] The sensitivity of the next generation of interferometric gravitational wave detectors will be limited in part by thermal noises of the optics. It has been proposed that using higher-order Laguerre-Gauss (LG) beams in the interferometers can reduce this noise. This thesis documents progress made in assessing the compatibility of higher-order LG beam technology with the existing precision interferometry framework used in the gravitational wave detector community. A numerical investigation was made into techniques for generating higher-order LG modes with a phase modulating surface. The optimal conditions for mode conversion were determined using fast Fourier transform (FFT) simulations, and predictions were made for the mode purity achievable with this method. Table-top experiments performed at Birmingham demonstrated the generation of higher-order LG modes using a spatial light modulator, and showed for the first time the feedback control of an optical cavity on resonance for higher-order LG modes. An increase in the purity of LG\(_{33}\) modes from 51% to over 99% upon transmission through the cavity was shown. Investigations were carried out at the Glasgow 10m prototype detector into the performance of the LG\(_{33}\) mode in a suspended 10m cavity, providing useful insights into the compatibility of LG modes with larger scale interferometers.

[发布机构] University:University of Birmingham;Department:School of Physics and Astronomy

[关键词] Q Science;QB Astronomy