Researches on Non-standard Optics for Advanced Gravitational Waves Interferometers
arXiv:0806.3065
Abstract
This thesis presents a collection of different researches on non-standard optics in view of enhancing the performances of the Advanced Gravitational waves interferometric detectors, where the thermal noise of the test masses is expected to be a limiting factor for their sensitivity. We provide a quantitative analysis of the impact of non-Gaussian beams on different kinds of thermal noises. We developed the theory of mesa beam, in view of a future implementation in advanced GW interferometers of the mesa beam idea, focusing on the analytical derivation of the quantities (i.e. beam width, divergence, propagation factor), which are chosen as ISO standard reference parameters for the characterization of an optical beam. We also analytically proved a new duality relation between optical cavities with non-spherical mirrors. The interest of the GW community in this new beam technology led us to the construction and testing of a prototype mesa beam Fabry-Perot cavity with Mexican-hat mirror. Part of the work of this thesis was devoted to the development of new simulation programs of optical systems. These programs provided the theoretical expected behaviour of our experiment, in particular cavity modes structure and misalignments sensitivity to be confronted with the experimental results. We also explored another complementary way of reducing the mirror thermal noise, beside the beam shaping, that is the multi-layered coating thickness optimization. We show it to be effective in reducing the coating noise and explore the possible implications for GW interferometers in terms of sensitivity. During this analysis we developed an independent model for the coating effective elastic parameters, which is based on the well understood subject of homogenization theory.
Ph.D. thesis, University of Pisa & LIGO-Caltech, 185 pages
References in corpus (10)
- Parametric Oscillatory Instability in Fabry-Perot (FP) Interferometer
- Thermal noise in interferometric gravitational wave detectors due to dielectric optical coatings
- Mechanical Loss in Tantala/Silica Dielectric Mirror Coatings
- Thermoelastic dissipation in inhomogeneous media: loss measurements and displacement noise in coated test masses for interferometric gravitational wave detectors
- A New Family of Light Beams and Mirror Shapes for Future LIGO Interferometers
- On the Analytic Structure of a Family of Hyperboloidal Beams of Potential Interest for Advanced LIGO
- Estimate of Tilt Instability of Mesa-Beam and Gaussian-Beam Modes for Advanced LIGO
- The implications of Mexican-hat mirrors: calculations of thermoelastic noise and interferometer sensitivity to perturbation for the Mexican-hat-mirror proposal for advanced LIGO
- Perspectives on Beam-Shaping Optimization for Thermal-Noise Reduction in Advanced Gravitational-Wave Interferometric Detectors: Bounds, Profiles, and Critical Parameters
- A duality relation between non-spherical mirror optical cavities and its application to gravitational-wave detectors