{"id":{"repo_id":"nus","oai_identifier":"oai:scholarbank.nus.edu.sg:10635/317028"},"canonical_url":"https://search.dev.ndltd.org/etd/nus/oai:scholarbank.nus.edu.sg:10635/317028","repository":{"repo_id":"nus","name":"National University of Singapore","base_url":"https://scholarbank.nus.edu.sg/oai/request"},"display":{"title":"CORRELATED PHOTON PAIRS AND MULTIPHOTON STATES FROM A COLD ATOMIC ENSEMBLE","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.","abstract_html":"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 <sup>87</sup>Rb 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_has_math":false,"creators":["LI YIFAN"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-08-01","date_published":"2025-08-01","updated_at":"2026-07-24T03:30:34Z","subjects":["four-wave mixing","nonlinear optics","cold atomic physics","quantum optics","photon pairs"],"languages":[],"rights":[],"rights_urls":["https://scholarbank.nus.edu.sg/bitstreams/5f546840-cb69-43d3-9a90-d844f8eae2e5/download"],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["LI YIFAN"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2025-08-01"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://scholarbank.nus.edu.sg/handle/10635/317028"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["four-wave mixing","nonlinear optics","cold atomic physics","quantum optics","photon pairs"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["https://scholarbank.nus.edu.sg/bitstreams/5f546840-cb69-43d3-9a90-d844f8eae2e5/download"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://scholarbank.nus.edu.sg/bitstreams/73a00b70-07fe-4728-98ad-6cc98dccef32/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Narrowband correlated photon pairs are vital for interfacing neutral atom systems and realizing distributed quantum networks. 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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. 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