Quantum metrology tools for enhancing time-resolved spectroscopy

Adamou, Dionysis (2026) Quantum metrology tools for enhancing time-resolved spectroscopy. PhD thesis, University of Glasgow.

Abstract

In conventional balanced-detection measurements, sensitivity can generally be improved by increasing the optical power. However, in many systems this approach reaches an upper bound beyond which increasing the probe power can damage the sample or degrade the measurement. In THz time-domain spectroscopy, this bound is set by nonlinear noise and measurement back-action. When this ceiling is reached by classical techniques, a potential avenue to improve the signal-to-noise ratio is by using quantum metrological resources. This work reports the development of a bright, ultrafast twin-beam source, exhibiting more than 6 dB of noise suppression up to microwatt optical power levels, together with an ultra-low-noise balanced photoreceiver with sub-shot-noise performance. Integrating these technologies into a THz-TDS system developed in collaboration with colleagues we demonstrate, for the first time to our knowledge, a measurable enhancement in sensitivity by harnessing quantum correlations when compared with a classical source under identical conditions. Although the implemented THz-TDS setup deviates from conventional polarimetric schemes, which typically achieve higher sensitivity, these results show that quantum methods can provide a sensitivity enhancement in field-resolved THz spectroscopy. Beyond this demonstration, the developed twin-beam source has clear potential for wider use as its brightness, stability and correlation strength make it an attractive candidate for ultrafast, differential transient absorption measurements.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: Q Science > QC Physics; T Technology > TA Engineering (General). Civil engineering (General)
• Colleges/Schools: College of Science and Engineering > School of Engineering
• Supervisor's Name: Clerici, Professor Matteo, Weaver, Professor Jonathan and Lyons, Dr. Ashley
• Date of Award: 2026
• Depositing User: Theses Team
• Unique ID: glathesis:2026-86052
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 23 Jun 2026 10:44
• Last Modified: 23 Jun 2026 10:48
• Thesis DOI: 10.5525/gla.thesis.86052
• URI: https://theses.gla.ac.uk/id/eprint/86052

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