Experiments Related to the Infra-Red Conversion of the Glasgow 10m Prototype Gravitational Wave Detector

Clubley, David Alexander (2002) Experiments Related to the Infra-Red Conversion of the Glasgow 10m Prototype Gravitational Wave Detector. PhD thesis, University of Glasgow.

Abstract

Large scale laser interferometric gravitational wave detectors are being constructed by research teams worldwide. The Japanese TAMA 300 interferometer is operational but still under development, the American LIGO detector is operating in a preliminary mode, the British-German GEO 600 interferometer is close to being fully operational and the French-Italian VIRGO project is not far behind. The development of these detectors is possible after nearly 30 years of research using smaller prototype interferometers. The Glasgow prototype interferometer has allowed the development of techniques relevent to all large scale detectors. This thesis describes recent experiments performed using the Glasgow proto-type interferometric gravitational wave detector to convert its laser and optics to operate at 1064 nm. This infra-red conversion brings it into line with the large scale detectors which will all operate with infra-red lasers. Associated with this conversion were related experiments testing optical components for GEO 600. An injection locked Nd:YAG laser system was constructed and characterised as the new laser source for the interferometer. Experiments to stabilise and measure the frequency noise properties of the laser were performed, using one of the Fabry-Perot cavities which make up the interferometer as a frequency analyser. The transference of the frequency properties of a highly stabilised master oscillator to the high power injection locked slave laser was verified. A measurement of the frequency noise around the relaxation oscillation of a Non Planar Ring Oscilator was performed and a new upper limit set. The detector was operated with the new laser source and the displacement sensitivity was close to being shot noise limited. A direct measurement of the thermal noise of a mirror mass was made by damping its mechanical Q-factor, thus making thermal noise the limiting noise source to the detector displacement sensitivity. A new detector displacement calibration technique was demonstrated using radiation pressure from a low power laser to move one of the detector mirrors. This was shown to be suitable as a calibration method for large scale detectors. GEO 600 optics were characterised and shown to be suitable for use. A new Brewster polariser was shown to have very low optical losses while maintaining a high extinction ratio. The additional phase noise around an electro optically applied phase modulation of the laser field was performed and shown to be at a level below that required for GEO 600. Finally experiments to make a single frequency Yb:YAG laser system are de-scribed. Yb:YAG may be the gain medium of choice for future detector up-grades where very much higher power lasers are required. A single frequency Yb:YAG source was required for testing high power Yb:YAG amplifiers which are currently being developed.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: Gavin Newton
• Keywords: Astronomy
• Date of Award: 2002
• Depositing User: Enlighten Team
• Unique ID: glathesis:2002-75966
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 19 Nov 2019 17:11
• Last Modified: 19 Nov 2019 17:11
• URI: https://theses.gla.ac.uk/id/eprint/75966