[Dissertation] Fundamental Limits to Single-Photon Detection

TL;DR

This dissertation develops a comprehensive quantum mechanical model of single-photon detection, integrating all detection stages within quantum information theory to better understand fundamental detection limits.

Contribution

It bridges the gap between theoretical and phenomenological models by constructing a realistic, fully quantum model of photodetection using POVMs.

Findings

Improved quantum limits for photon counting.

Quantum network approaches to single-photon detection.

Method to project onto arbitrary single-photon wavepackets.

Abstract

Quantum mechanics cements the intimate relationship between the nature of light and its detection. Historically, quantum theories of photodetection have generally fallen into two categories: the first tries to determine what quantum field observable is measured when photoelectrons are detected, laying the theoretical groundwork for photodetection being possible. The second type are phenomenological theories, which take great care to model the details of specific photodetectors. In this dissertation, we fill in the gap between these two models in the modern literature on photodetection by constructing a fully quantum mechanical and sufficiently realistic model that includes all stages of the photodetection process: transmission, amplification, and a final classical measurement. We accomplish this within the framework of quantum information theory using the language of positive operator valued measures (POVMs). This dissertation contains material previously published in three papers: Propp, Tz. B & van Enk, S. J. (2019). On nonlinear amplification: improved quantum limits for photon counting. Optics Express 27, 16, 23454-23463. Propp, Tz. B & van Enk, S. J. (2019). Quantum networks for single photon detection. Physical Review A, 100, 033836. Propp, Tz. B & van Enk, S. J. (2020). How to project onto an arbitrary single-photon wavepacket. Physical Review A, 102, 053707.