{"id":{"repo_id":"cambridge","oai_identifier":"oai:www.repository.cam.ac.uk:1810/316214"},"canonical_url":"https://search.dev.ndltd.org/etd/cambridge/oai:www.repository.cam.ac.uk:1810/316214","repository":{"repo_id":"cambridge","name":"Cambridge University","base_url":"https://api.repository.cam.ac.uk/server/oai/request"},"display":{"title":"Ultrafast Ultra-confined Plasmon Phonon Interactions","abstract":"The research contained within this thesis focuses on understanding and interrogating nanometrically conﬁned ultrafast plasmon-phonon interactions. Nanometric plasmonic conﬁnement is achieved by coupling the charge oscillations of a single gold nanoparticle to a gold substrate. This conﬁnes the plasmonic ﬁeld to the single nanometre gap separating the two and is known as the NanoPar- ticle on Mirror (NPoM) structure. The ﬁrst half of this thesis demonstrates the viability of using the coupling between conﬁned plasmonic and acoustic modes as a sensitive nanomechanical probe. Initially this coupling allows us to discover the NPoM “bouncing mode” by performing ultrafast pump- probe spectroscopy on single constructs. Thorough ﬁnite element method simulations allow us to create a simple analytical model relat- ing the nanoparticle-substrate contact area to the bouncing mode period. This means that by measuring the bouncing mode period of a single NPoM structure we can calculate the size of the contact; a task impossible by any other means. The second half of this thesis is dedicated to furthering our under- standing of ultrafast molecular-phonon plasmon interactions. To fa- cilitate this we develop and utilise a fully automated time-resolved Coherent Anti-Stokes Raman Spectroscopy (tr-CARS) setup to mea- sure an acceleration of the vibrational decay of 2-mercaptopyridine within NPoM from 0 . 96 ps (determined from bulk Raman linewidth measurements) to far below 0 . 5 ps . To understand the origin of this acceleration we perform a series of power dependent Surface En- hanced Raman Spectroscopy (SERS) measurements on over 1000 NPoM constructs. We determine the acceleration to be most likely due to anharmonic phonon coupling driven by the high phonon pop- ulations induced by ultrafast pulses in plasmonic cavities. The power- series also reveals the presence of a previously unknown saturation eﬀect due to intermolecular anharmonicity.","abstract_html":"The research contained within this thesis focuses on understanding and interrogating nanometrically conﬁned ultrafast plasmon-phonon interactions. Nanometric plasmonic conﬁnement is achieved by coupling the charge oscillations of a single gold nanoparticle to a gold substrate. This conﬁnes the plasmonic ﬁeld to the single nanometre gap separating the two and is known as the NanoPar- ticle on Mirror (NPoM) structure. The ﬁrst half of this thesis demonstrates the viability of using the coupling between conﬁned plasmonic and acoustic modes as a sensitive nanomechanical probe. Initially this coupling allows us to discover the NPoM “bouncing mode” by performing ultrafast pump- probe spectroscopy on single constructs. Thorough ﬁnite element method simulations allow us to create a simple analytical model relat- ing the nanoparticle-substrate contact area to the bouncing mode period. This means that by measuring the bouncing mode period of a single NPoM structure we can calculate the size of the contact; a task impossible by any other means. The second half of this thesis is dedicated to furthering our under- standing of ultrafast molecular-phonon plasmon interactions. To fa- cilitate this we develop and utilise a fully automated time-resolved Coherent Anti-Stokes Raman Spectroscopy (tr-CARS) setup to mea- sure an acceleration of the vibrational decay of 2-mercaptopyridine within NPoM from 0 . 96 ps (determined from bulk Raman linewidth measurements) to far below 0 . 5 ps . To understand the origin of this acceleration we perform a series of power dependent Surface En- hanced Raman Spectroscopy (SERS) measurements on over 1000 NPoM constructs. We determine the acceleration to be most likely due to anharmonic phonon coupling driven by the high phonon pop- ulations induced by ultrafast pulses in plasmonic cavities. The power- series also reveals the presence of a previously unknown saturation eﬀect due to intermolecular anharmonicity.","abstract_has_math":false,"creators":["Deacon, William"],"institution":"University of Cambridge","degree_name":"Doctor of Philosophy (PhD)","degree_level":"Doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Baumberg, Jeremy"],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019-03-01","date_published":"2019-03-01","updated_at":"2026-07-22T22:24:21Z","subjects":["Physics","photonics","plasmonics","ultrafast","Raman"],"languages":["eng"],"rights":[],"rights_urls":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/8e08aa2d-a845-4883-8d38-f275c6de9b6a/download","https://www.rioxx.net/licenses/all-rights-reserved/"],"identifier_entries":[]},"links":{"outbound_url":"https://doi.org/10.17863/CAM.63322","outbound_label":"DOI","outbound_source":"dc:identifier.doi"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Baumberg, Jeremy"]},{"key":"dc:creator","label":"Author","values":["Deacon, William"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2019-03-01"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cambridge"]},{"key":"dc:relation.isreferencedby.uri","label":"Dc Relation Isreferencedby URI","values":["https://www.repository.cam.ac.uk/handle/1810/316214"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Doctor of Philosophy (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Physics","photonics","plasmonics","ultrafast","Raman"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/8e08aa2d-a845-4883-8d38-f275c6de9b6a/download","https://www.rioxx.net/licenses/all-rights-reserved/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.doi","label":"DOI","values":["10.17863/CAM.63322"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/4db90559-65c5-459f-89fc-561154dc2f31/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The research contained within this thesis focuses on understanding and interrogating nanometrically conﬁned ultrafast plasmon-phonon interactions. 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The second half of this thesis is dedicated to furthering our under- standing of ultrafast molecular-phonon plasmon interactions. To fa- cilitate this we develop and utilise a fully automated time-resolved Coherent Anti-Stokes Raman Spectroscopy (tr-CARS) setup to mea- sure an acceleration of the vibrational decay of 2-mercaptopyridine within NPoM from 0 . 96 ps (determined from bulk Raman linewidth measurements) to far below 0 . 5 ps . To understand the origin of this acceleration we perform a series of power dependent Surface En- hanced Raman Spectroscopy (SERS) measurements on over 1000 NPoM constructs. We determine the acceleration to be most likely due to anharmonic phonon coupling driven by the high phonon pop- ulations induced by ultrafast pulses in plasmonic cavities. 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The ﬁrst half of this thesis demonstrates the viability of using the coupling between conﬁned plasmonic and acoustic modes as a sensitive nanomechanical probe. Initially this coupling allows us to discover the NPoM “bouncing mode” by performing ultrafast pump- probe spectroscopy on single constructs. Thorough ﬁnite element method simulations allow us to create a simple analytical model relat- ing the nanoparticle-substrate contact area to the bouncing mode period. This means that by measuring the bouncing mode period of a single NPoM structure we can calculate the size of the contact; a task impossible by any other means. The second half of this thesis is dedicated to furthering our under- standing of ultrafast molecular-phonon plasmon interactions. To fa- cilitate this we develop and utilise a fully automated time-resolved Coherent Anti-Stokes Raman Spectroscopy (tr-CARS) setup to mea- sure an acceleration of the vibrational decay of 2-mercaptopyridine within NPoM from 0 . 96 ps (determined from bulk Raman linewidth measurements) to far below 0 . 5 ps . To understand the origin of this acceleration we perform a series of power dependent Surface En- hanced Raman Spectroscopy (SERS) measurements on over 1000 NPoM constructs. We determine the acceleration to be most likely due to anharmonic phonon coupling driven by the high phonon pop- ulations induced by ultrafast pulses in plasmonic cavities. 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