Applications of Precision Interferometry in Quantum Measurement and Gravitational Wave Detection

Smetana, Jiri ORCID: https://orcid.org/0000-0002-7277-6671 (2023). Applications of Precision Interferometry in Quantum Measurement and Gravitational Wave Detection. University of Birmingham. Ph.D.

Preview

Smetana2023PhD.pdf
Text - Accepted Version
Available under License All rights reserved.
Download (19MB) | Preview

Abstract

Interferometry sits at the forefront of precision measurement. This versatile technique is used to detect the smallest signals in the universe, including microscopic fluctuations of quantum phenomena, and gravitational waves. In this thesis, I present the development of (i) new interferometer configurations, (ii) new interferometric sensors, and (iii) quantum-limited systems of fundamental physics importance.

Concerning contribution (i), I present work on two new interferometer configurations for gravitational-wave detection. (a) Theoretical analysis of an optomechanical filter cavity that acts as a quantum amplifier. The purpose of the amplifier is to enhance the quantum-limited sensitivity of future detectors. The technique uses a dual frequency- and time-domain approach to verify the effect. (b) A high-frequency design that is capable of measuring the signal from a post-merger neutron star collapse. My contribution concerns the modelling of classical noise sources in the region of the spectrum where the conventional noise models lose their validity.

The device comprising contribution (ii) is a compact, interferometric displacement sensor. The position sensors and inertial sensors on contemporary detectors are limited by readout noise, which couples into the gravitational-wave readout channel. The sensor presented utilises the sharp response of a Michelson interferometer, with the additional use of deep frequency modulation. I show that the device improves upon existing displacement sensors by a factor of 300.

Contribution (iii) concerns the measurement of quantum noise over a broad band in a macroscopic system. Future gravitational-wave detectors will be able to operate at a quantum-limited level of sensitivity at the level of the so-called standard quantum limit. However, this limit has not yet been reached, despite the opportunities to study matters of fundamental physics importance that such a system would bring. I present a high-finesse, suspended optical cavity theoretically capable of reaching this level of operation. I analyse the performance of the main aspects of the experiment and present initial results from the operation of the cavity.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):