Optimized resources for efficient optical quantum information processing and sensing

This dissertation explores the role of optimized resources in facilitating efficient optical quantum information processing and sensing. Three key applications are considered: quantum interferometry, detector characterization, and multi-photon processing. For each application, we examine the underlying quantum resource states and quantum technology resources. Careful attention is paid to how these resources can be optimized to maximize the efficiency of the overarching application in terms of resources consumed, whether photonic, temporal, or infrastructural. Such optimization is an important step in fully realizing the potential of quantum science as it emerges from the laboratory and into the mainstream. For quantum interferometry, we investigate the traditional trade-offs between two-photon quantum interference and single-photon classical interference in terms of measurement resolution and resilience against optical loss and background. We show how we can overcome these trade-offs by replacing conventional single photons with highly non-degenerate energy-entangled photons, which are more optimized for achieving high information content on a per-photon basis. In combination with a specialized dual-wavelength interferometer, our high per-photon information efficiency allows us to achieve nanometer-scale resolution in a matter of seconds with only O(10^4) photon pairs. We then show how this entanglement-enhanced quantum sensing modality can allow for new studies in challenging regimes, such as characterizing lossy thin films or detecting distant vibrations. Then, for detector characterization, we consider the instrumental role of photon detectors in various optical quantum science protocols. As these protocols expand into spectral bands with growing technological applications, such as the mid-infrared, there is a developing need to characterize suitable detectors, with their efficiencies being one of the most important metrics. Typical methods for efficiency characterization, whether classical or quantum, can face the challenge of being infrastructure-intensive, with some requiring resources such as independent reference standards or large bulk-optics apparatuses. To help realize a resource-efficient characterization system for mid-infrared detectors, we have developed a compact and portable solution involving highly non-degenerate photon pairs produced by a fiber-coupled waveguide device. We evaluate the performance of early prototypes and identify next steps for improved device engineering. Lastly, for multi-photon processing, we focus on the single-photon source, given its key role in preparing the required photonic states. From a scalability perspective, efficient single-photon generation is essential for performing many large-scale multi-photon protocols within useful timescales. To meet this requirement, we explore how multiplexing techniques allow us to pair heralded single photons with photon routing, storage, and counting technologies to realize an efficient single-photon source. We then discuss our efforts to implement and integrate optimized versions of these technologies to address limitations faced by earlier implementations with regard to preparing pure single photons at a high rate. This discussion includes an in-depth analysis of our work related to realizing an efficient photon-number-resolving detector.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Lualdi, Colin P.

Contributors dc:contributor

• Kwiat, Paul
• Goldschmidt, Elizabeth
• Bogdanov, Simeon
• Song, Jun

• Classical interference
• Correlated photons
• Detector characterization
• Entanglement
• Entanglement-enhanced sensing
• Heralded single photons
• Highly non-degenerate entanglement
• Highly non-degenerate photon pairs
• Interferometry
• Multi-photon processing
• Multiplexing
• Optical quantum information processing
• Optimized resources
• Photon counting
• Photon routing
• Photon storage
• Photon-number-resolving detection
• Quantum information
• Quantum information science
• Quantum interference
• Quantum metrology
• Quantum optics
• Quantum photonics
• Quantum resource states
• Quantum sensing
• Quantum technology resources
• Single-photon source
• Two-photon interference
• Waveguide optical devices

Statement dc:rights

• Copyright 2025 Colin P. Lualdi

Language dc:language

eng

Handle dc:identifier

https://hdl.handle.net/2142/132661

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/132661