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Enhancing the QUEST experiment with a coin sized Output Mode Cleaner for improved sensitivity to Quantum Gravity signatures

Griffiths, William 2023. Enhancing the QUEST experiment with a coin sized Output Mode Cleaner for improved sensitivity to Quantum Gravity signatures. PhD Thesis, Cardiff University.
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This PhD thesis details the work undertaken at Cardiff University on the quantum enhanced spacetime (QUEST) experiment and at laser interferometer gravitational-wave observatory (LIGO) Livingston, and it is structured as follows. Chapter one gives an overview of the theory about the three major science goals for the QUEST experiment: quantum gravity, high frequency gravitational waves and scalar field dark matter. Chapter two is a review of the foundational scientific principles and experimental methods used throughout the thesis. Chapter three is dedicated to describing the QUEST experiment, from the design to the commissioning up to the last results achieved at the time of writing. Chapter four describes the output mode cleaner (OMC), an optical cavity in the detection path of QUEST which facilitates the use of high power and is essential for QUEST's unprecedented sensitivity level goal. It was designed from first principles and has been brought to completion with a working control loop and comprehensive characterisation. Chapter five is related to a four month fellowship at LIGO Livingston. The project goal was to develop a new method of acquiring the science laser vs X-arm length error signal by cancelling the frequency noise introduced by an optical fiber. New fiber optic breadboards were designed and installed in the per-stabilised laser enclosure and the x-end station during the fellowship and the results do show promise. I am the joint first PhD student to graduate on QUEST. The other, Sander Vermeulen, worked on the data acquisition for QUEST. The Covid-19 lockdowns somewhat impacted my work. As an experimentalist, losing access to the lab for several weeks certainly delayed progress. Nonetheless, projects were sufficiently concluded to graduate.

Item Type: Thesis (PhD)
Date Type: Completion
Status: Unpublished
Schools: Physics and Astronomy
Subjects: Q Science > QC Physics
Uncontrolled Keywords: QUEST Quantum gravity detector Gravitational wave detector Dark matter detector Interferometer Interferometry Power recycled interferometer Co-located interferometers Table-top interferometer Quantum enhanced interferometer Output mode cleaner LIGO Glass beam dumps V-shaped baffles V-shaped beam dumps Black glass beam dumps
Funders: Science & Technology Facilities Council (STFC)
Date of First Compliant Deposit: 3 October 2023
Last Modified: 05 Oct 2023 09:19

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