CORRELATED PHOTON PAIRS AND MULTIPHOTON STATES FROM A COLD ATOMIC ENSEMBLE
type: CreativeWork
description: Narrowband correlated photon pairs are vital for interfacing neutral atom systems and realizing distributed quantum networks. This thesis presents the realization and characterization of a high-brightness, temporally correlated photon-pair source at near-resonant wavelengths of 780 nm and 795 nm in an optically dense cold 87Rb ensemble. The source is based on a spontaneous four-wave mixing process implemented in a double-Λ energy-level configuration. By systematically varying the pump intensities, detunings, and optical depth, we optimized the photon-pair generation and demonstrated a tunable spectral bandwidth governed by electromagnetically induced transparency. The pair production exhibits quartic scaling with optical depth, revealing the crucial role of collective pair emission beyond independent-emitter models. The generated two-mode squeezed vacuum enables time-resolved measurements of higher-order photon correlations, providing direct evidence of genuine multiphoton states. Building on this foundation, the thesis further explores photon-triplet generation via composite spontaneous six-wave mixing, offering a pathway toward scalable multiphoton quantum light sources compatible with atomic quantum memories.
abstract: Narrowband correlated photon pairs are vital for interfacing neutral atom systems and realizing distributed quantum networks. This thesis presents the realization and characterization of a high-brightness, temporally correlated photon-pair source at near-resonant wavelengths of 780 nm and 795 nm in an optically dense cold 87Rb ensemble. The source is based on a spontaneous four-wave mixing process implemented in a double-Λ energy-level configuration. By systematically varying the pump intensities, detunings, and optical depth, we optimized the photon-pair generation and demonstrated a tunable spectral bandwidth governed by electromagnetically induced transparency. The pair production exhibits quartic scaling with optical depth, revealing the crucial role of collective pair emission beyond independent-emitter models. The generated two-mode squeezed vacuum enables time-resolved measurements of higher-order photon correlations, providing direct evidence of genuine multiphoton states. Building on this foundation, the thesis further explores photon-triplet generation via composite spontaneous six-wave mixing, offering a pathway toward scalable multiphoton quantum light sources compatible with atomic quantum memories.
author: LI YIFAN
keywords: four-wave mixing, nonlinear optics, cold atomic physics, quantum optics, photon pairs
license: https://scholarbank.nus.edu.sg/bitstreams/5f546840-cb69-43d3-9a90-d844f8eae2e5/download
date published: 2025-08-01
date modified: 2026-07-24T03:30:34Z
provider: National University of Singapore
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: National University of Singapore