Дисертації з теми "Plasmonic metal nanostructures"
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Abb, Martina. "All-optical control of hybrid plasmonic semiconductor-metal nanostructures." Thesis, University of Southampton, 2012. https://eprints.soton.ac.uk/340900/.
Повний текст джерелаGenç, Aziz. "Plasmonic nanoengineering in hollow metal nanostructures: an electron energy-loss spectroscopy study." Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/305101.
Повний текст джерелаMetallic nanostructures have received great attention due to their ability to generate surface plasmon resonances, which are the collective oscillations of conduction band electrons in a metal excited by an electromagnetic field. Ever-increasing interest in plasmonic metal nanostructures has emerged into the field of plasmonics, which can be defined as the science and technology of generation, control and manipulation of excitations resulted by the light-matter interactions. Plasmonic nanostructures have been used in many different applications spanning over the fields of biology, physics, chemistry, engineering and medicine. For instance, they are widely used in sensing, surface enhanced Raman spectroscopy (SERS), plasmon-enhanced solar cells, photodetectors, drug delivery and cancer therapy as well as nanolasers, invisibility cloaks and quantum computing. It is very-well known that plasmonic properties of metallic nanostructures are greatly affected by different parameters such as the size, shape, composition and local environment. Thus, understanding and manipulating the plasmonic properties at the nanoscale is essential to fabricate devices with the desired features. In this thesis manuscript, we present a detailed characterization study on the plasmonic properties hollow AuAg nanostructures by using electron energy-loss spectroscopy (EELS) technique. Hollow nanostructures are known to have enhanced plasmonic properties compared to their solid counterparts due to the coupling of inner and outer plasmon resonances. This study involves the first examples of spatially resolved plasmon mapping in hollow AuAg nanostructures such as nanoboxes and nanotubes, both in 2D and 3D. This thesis manuscript is divided into six chapters. Chapter 1 is the introduction, which includes the theoretical background of surface plasmon resonances, the reviews of different parameters that affect the plasmonic properties of metal nanostructures, the application areas of plasmonic nanostructures and characterization techniques used to determine the plasmonic properties. In Chapter 2, details of the methodology are presented. Experimental results and accompanying simulations are presented in Chapters 3, 4 and 5, where we perform a detailed characterization and modeling studies on complex metal nanostructures. Finally, Chapter 6 includes the general conclusions of the whole thesis and some future works that are already on-going or planned to be done in the near future.
Polyushkin, Dmitry Konstantinovich. "Investigation of plasmonic response of metal nanoparticles to ultrashort laser pulses." Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/13521.
Повний текст джерелаWeber, Verena. "Plasmonic nanostructures for the realization of sensor based on surface enhanced Raman spectroscopy." Doctoral thesis, Università degli studi di Padova, 2014. http://hdl.handle.net/11577/3423838.
Повний текст джерелаLa Plasmonica si occupa dell’interazione di una radiazione elettromagnetica di opportuna lunghezza d’onda con gli elettroni di conduzione di un metallo. L’oscillazione collettiva degli elettroni, indotta da questa interazione, è chiamata appunto Risonanza Plasmonica. La risonanza plasmonica di superficie localizzata avviene quando gli elettroni coinvolti sono quelli di superficie di un metallo nanostrutturato con dimensioni minori o comparabili alla lunghezza d’onda di eccitazione. Da questa eccitazione deriva una forte amplificazione del campo elettromagnetico locale, localizzato nelle immediate vicinanze della nanostruttura metallica. Tale amplificazione, unita a una tecnica di rivelazione spettroscopica specifica, quale la spettroscopia Raman, può essere sfruttata per la realizzazione di sensori molecolari. La tecnica Raman è conosciuta come altamente specifica, perché in grado di fornire uno spettro caratteristico della singola molecola, identificandone univocamente la presenza e la costituzione. La sua maggiore limitazione, però, è la bassa sensibilità. Ponendo l’analita in prossimità di un substrato plasmonico, proprio nella regione di forte amplificazione del campo locale, la sensibilità di rivelazione viene fortemente aumentata, dando origine alla spettroscopia Raman amplificata da superfici (SERS). La prima parte del presente lavoro è focalizzata sulla sintesi e sulla caratterizzazione di nanoparticelle d’argento, d’oro e di nano gusci d’oro (chiamati nanoshell) e sul loro impiego per la realizzazione di substrati SERS, sia in soluzione colloidale che su substrato solido. L’utilizzo di differenti nanostrutture metalliche, dà la possibilità di sfruttare la risonanza plasmonica localizzata di superficie in un’ampia regione spettrale, che si estende dal visibile al vicino infrarosso. La caratterizzazione ottica e morfologica delle nanostrutture è stata effettuata con tecniche convenzionali, come la spettroscopia di assorbimento UV-visibile, il SERS, la microscopia elettronica a trasmissione e la microscopia a forza atomica. Ad esse è stata affiancata anche una tecnica raramente usata nell’ambito della plasmonica: la spettroscopia fotoacustica. Questa può fornire informazioni riguardanti il contributo di assorbimento, all’estinzione totale, di una nanostruttura plasmonica. Da una rigorosa misura dei fattori di amplificazione e delle proprietà di fotoacustica al variare della lunghezza d’onda, possono essere fatte alcune considerazioni riguardanti la possibile relazione tra l’estinzione (proprietà di campo lontano) e l’ amplificazione SERS (proprietà di campo vicino). Le misure dei profili di eccitazione SERS su substrati plasmonici in liquido e su supporto solido, hanno evidenziato la presenza di hot spots, ovvero di zone fortemente amplificate dall’interazione di due o più nanostrutture. I substrati SERS solidi sono risultati chimicamente stabili, omogenei e riproducibili; essi presentano valori di fattori di amplificazione attorno a 104-105. In soluzione colloidale, i fattori di amplificazione delle nanostrutture hanno raggiunto valori nell’intervallo 103-106, dipendentemente dal tipo di nanostruttura metallica investigata. Le misure di fotoacustica effettuate su soluzioni colloidali di nanoshell d’oro si sono rivelate in accordo con le predizioni teoriche di letteratura. Nella seconda parte del lavoro, i substrati plasmonici, realizzati principalmente con nanoparticelle e nanoshell d’oro, sono stati impiegati per la realizzazione di sensori SERS per la rivelazione di specie chimiche e biologiche. É stato realizzato un sensore di composti tossici aromatici volatili, accoppiando un substrato plasmonico con un film poroso di sol gel ibrido organico-inorganico. La componente organica della matrice sol gel è stata appositamente scelta per la sua alta affinità a composti aromatici, quali lo Xilene. È stata dimostrata l’amplificazione dei segnali della matrice da parte della componente plasmonica, ma si sono riscontrati alcuni problemi nella rivelazione delle molecole di analita attraverso il SERS. La difficoltà nella rivelazione è probabilmente dovuta al veloce deadsorbimento dello Xilene dalla matrice a causa del forte riscaldamento locale causato dalla radiazione laser. Nonostante questo, si è comunque dimostrata l’aumentata efficienza del sensore progettato, rispetto ai suoi componenti singoli. La seconda applicazione studiata ha riguardato la realizzazione di un sistema analita-accettore innovativo, che può essere utilizzato per diverse applicazioni bioanalitiche; esso è basato sull’interazione tra un cromoforo diazobenzenico (HABA) e il suo anticorpo specifico. Alla base dell’applicazione si trova una proprietà interessante del suddetto cromoforo, che è quella di cambiare la sua struttura molecolare, passando da una forma azo alla forma idrazo, dopo aver interagito con il suo anticorpo specifico. Questa variazione nella struttura molecolare può essere sfruttata per la rivelazione dell’avvenuta interazione analita-accettore, mediante SERS. Alcuni derivati di questo cromoforo sono stati sintetizzati e caratterizzati in modo da poter essere adsorbiti su un substrato SERS, che viene successivamente incubato in una soluzione di anticorpo. I segnali SERS della molecola di HABA sono risultati ben visibili sia sui substrati di nanoparticelle che di nanoshell d’oro. Purtroppo non è stato possibile rivelare la variazione strutturale del cromoforo, in quanto gli anticorpi, estratti in vivo da due coniglietti, inducono solo un parziale cambio di struttura, rendendo la rivelazione SERS alquanto difficile.
Kalinic, Boris. "Synthesis and characterization of plasmonic nanostructures with controlled geometry for photonic applications." Doctoral thesis, Università degli studi di Padova, 2014. http://hdl.handle.net/11577/3423850.
Повний текст джерелаLo scopo del presente lavoro di tesi è l’analisi dell’interazione di nanostrutture plasmoniche e pre-plasmoniche con un emettitore. Lo studio è stato condotto seguendo diversi approcci, ma sempre con il fine di confrontare i risultati sperimentali con modelli teorici sia già noti che nuovi, in modo da comprendere appieno la natura foto-fisica dell’interazione. In questo senso nell’ambito della presente tesi diverse nano-architetture sono state sintetizzate ed accoppiate con film sottili di silice drogata con erbio. La scelta dell’erbio come emettitore è stata dettata dalla sua grande importanza tecnologica della terra rara nella fotonica e nell’optoelettronica, associata alla caratteristica emissione radiativa a 1540nm, che si trova nella finestra di minimo assorbimento ottico della silice. Per questa ragione il primo passo dell’attività di ricerca è stato volto all’ottimizzazione delle proprietà di fotoluminescenza dello ione erbio in silice. Quando un emettitore è posto in prossimità di un film sottile le sue proprietà ottiche vengono modificate. Per descrivere tale variazione è necessario tenere conto di contributi differenti: la variazione della densità locale degli stati dovuta alla riflessione all’interfaccia, l’accoppiamento della radiazione emessa con plasmoni di superficie propaganti sull’interfaccia metallo-dielettrico e infine la dissipazione nel film. Tutti questi aspetti sono stati studiati in dettaglio per film di diversi materiali, dimostrando che un ottimo controllo sul tempo di vita dello stato eccitato può essere ottenuto agendo sulle proprietà dielettriche del film e sulla distanza di separazione tra l’emettitore e l’interfaccia. La nanostrutturazione del film può offrire ulteriori opportunità nella modifica delle proprietà ottiche di un emettitore. Tra le diverse nanostrutture plasmoniche, i nanohole arrays (NHAs) possono essere visti come i candidati ideali per questo scopo grazie alla loro trasmissione ottica straordinaria (EOT): a determinate lunghezze d’onda definite dalla periodicità dei buchi e dalle proprietà dielettriche dei materiali coinvolti, la luce trasmessa attraverso il NHA è ordini di grandezza più grande rispetto a quella predetta dalla teoria classica della diffrazione. Quando il picco della EOT è risonante con la lunghezza d’onda di emissione dell’emettitore, è stato dimostrato un forte accoppiamento plasmonico che porta ad un marcato accorciamento del tempo di vita nella quasi assenza di dissipazione nella nanostruttura. Il miglioramento delle proprietà ottiche di un emettitore può essere ottenuto non solamente agendo sulla parte emissiva del processo, ma anche aumentando la probabilità di eccitazione. A questo scopo, una possibilità interessante è offerta dalla sensitizzazione da aggregati metallici ultra-piccoli ottenuti per impiantazione ionica. Cluster di metalli nobili composti da 10–20 atomi possono infatti assorbire efficientemente la radiazione di eccitazione attraverso transizioni interbanda e trasferire l’energia a un emettitore posto nelle vicinanze, agendo in questo modo da efficienti nanoantenne. Tale interazione può portare ad un aumento della sezione d’urto di eccitazione efficace di diversi ordini di grandezza. Infine, tutti questi risultati hanno permesso lo sviluppo di modelli predittivi che possono essere utilizzati nella progettazione di nuovi dispositivi per diverse applicazioni fotoniche
Liyanage, Dilhara. "Efficient Integration of Plasmonic and Excitonic Properties of Metal and Semiconductor Nanostructures via Sol-Gel Assembly." VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/4768.
Повний текст джерелаFrare, Maria Chiara. "Opto-thermal properties of plasmonic metal nanostructures in solution and in polymer matrix for optical limiting protection against cw laser." Doctoral thesis, Università degli studi di Padova, 2014. http://hdl.handle.net/11577/3424088.
Повний текст джерелаLo sviluppo delle nanotecnologie ha fornito una varietà di nanostrutture metalliche con proprietà ottiche uniche utili per diverse applicazioni. Le nanoparticelle metalliche presentano una forte amplificazione delle proprietà ottiche associate al plasmone di risonanza superficiali (LSPR): in questo lavoro abbiamo studiato le proprietà ottiche di nanoparticelle d’oro (AuNPs) con diverse tecniche. La grande cross section di assorbimento delle AuNPs accoppiata con la rapido decadimento non radiativo e la scarsa efficienza di decadimento rendono efficace la conversione di luce in calore: le alte temperature raggiunte possono essere utilizzate per terapia fototermica, conversione luminosa in dispositivi fotovoltaici, ma il nostro interesse si è focalizzato sull’applicazione nella limitazione ottica contro laser in continuo (cw). Lo studio della conversione termica della luce incidente può essere utilizzato per la realizzazione di dispositivi per la protezione dell’occhio contro danni accidentali o intenzionali. Un buon dispositivo di protezione dovrebbe essere un materiale intelligente in grado di attivarsi sopra una certa soglia di intensità, con un ampio intervallo di attività e a diverse lunghezze d’onda. Quest’ultima proprietà è di particolare interesse in ambito militare per la protezione contro dispositivi laser di puntamento o armi accecanti di lunghezze d’onda non note a priori. In questo caso sono i filtri passivi per specifiche lunghezze d’onda attualmente utilizzati risultano inefficaci data la loro alta selettività e scarsa versatilità. L’irraggiamento di un limitatore ottico con un raggio laser cw focalizzato induce un assorbimento dell’energia che viene rapidamente convertito in un riscaldamento locale e la formazione di un gradiente di temperatura che corrisponde ad una variazione di indice di rifrazione attraverso il campione. In questo modo anche un campione piatto agisce come una lente focalizzante o defocalizzante e diffonde la luce. Abbiamo studiato diversi aspetti del fenomeno, come descritto in seguito, per ottenere un dispositivo a stato solido con un ampio intervallo di attività e una risposta rapida. Nella prima parte sperimentale di questa tesi sono state sintetizzate diverse nanostrutture, a partire da nanoparticelle d’oro, nanoshells e nanorods con aspect ratio differenti, al fine di ottenere risonanze plasmoniche in un ampio intervallo dello spettro visibile. Le nanostrutture sono state in seguito funzionalizzate con molecole di fulleropirrolidina tiolata (FULP-SH) per combinare il processo di rilassamento termico con uno più rapido. Un limitatore ottico per un dispositivo di protezione deve essere preferibilmente solido, e quindi lo studio delle proprietà ottiche è stato effettuato anche in matrice, in particolare in polycarbonato (PC), scelto per le sue ottime qualità ottiche. La produzione dei film e l’inglobamento delle nanoparticelle ha richiesto degli studi sulla funzionalizzazione e la stabilizzazione delle nanostrutture sintetizzate in solvente acquoso. Abbiamo caratterizzato la morfologia e le proprietà ottiche lineari con tecniche convenzionali: microscopia a trasmissione elettronica (TEM), che fornisce informazioni sulle dimensioni e la forma delle nanostrutture al fine di implementarne la sintesi, spettroscopia UV-Visibile che correla le strutture con le proprietà di estinzione, e la spettroscopia Raman che ha verificato l’effettiva funzionalizzazione dei sistemi con le molecole organiche. Nella seconda parte del progetto abbiamo studiato le risposte ottiche non lineari di questi promettenti sistemi per poterne modulare le proprietà. Attraverso la tecnica Z-scan siamo stati in grado di definire la natura del meccanismo di defocalizzazione e di ottenere i parametri non lineari che ci hanno permesso di confrontare i nostri risultati con quelli attualmente presenti in letteratura. Misure di limitazione ottica hanno dato informazioni sull’efficacia di protezione dei nostri sistemi. Grazie alla semplicità di funzionalizzazione delle nanoparticelle abbiamo individuato delle nuove e promettenti proprietà per un dispositivo di protezione a stato solido. In primo luogo abbiamo studiato le proprietà di limitazione ottica di nanoparticelle in soluzione per identificare la tipologia di funzionamento. In seguito i risultati sono stati confrontati con quelli ottenuti con nanoparticelle funzionalizzate con FULP-SH. In questo modo abbiamo tentato di associare al processo di rilassamento termico un meccanismo più rapido, in modo da ridurre maggiormente la trasmittanza e migliorare l’efficienza di limitazione. Abbiamo quindi verificato l’efficacia della strategia utilizzata evidenziando un miglioramento della limitazione ottica in un tempo inferiore. Le misure di limitazione ottica eseguite su nanoparticelle in matrice di PC hanno dato ottimi risultati, paragonabili a quelli ottenuti in soluzione. Un primo di studio di matrici differenti si è concentrato sulla fibroina della seta, scelta per la semplicità di inglobamento delle nanoparticelle. Inoltre questo sistema AuNPs-fibroina potrebbe trovare sbocco anche in diverse applicazioni: grazie alla biocompatibilità della matrice ed alla sua solubilità graduale in acqua potrebbe essere usato per il rilascio controllato di farmaci. Studi preliminari scoraggerebbero l’utilizzo di questo sistema nella limitazione ottica ma possono essere comunque considerate altre applicazioni. Le nanoparticelle in fibroina possono infatti essere facilmente trasformate in strutture porose: un’idea potrebbe essere quella di utilizzarle come sensori per campioni in soluzione con caratterizzazione Raman amplificata (SERS), combinando l’alta porosità e la presenza di strutture plasmoniche. Nell’ultima parte abbiamo confrontato le proprietà termiche dei nostri sistemi attraverso studi di fotoacustica che ci hanno permesso di discriminare il contributo assorbitivo dall’estinzione totale e di scegliere il sistema migliore con alta trasmittanza lineare e basse soglie di attivazione nonlineari
Neranon, Kitjanit. "Synthesis and Applications of Dynamic Multivalent Nanostructures." Doctoral thesis, KTH, Organisk kemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-177280.
Повний текст джерелаQC 20151119
Jain, Prashant K. "Plasmons in assembled metal nanostructures." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/28207.
Повний текст джерелаCommittee Chair: El-Sayed, Mostafa A.; Committee Member: Lyon, L. Andrew; Committee Member: Sherrill, C. David; Committee Member: Wang, Zhong Lin; Committee Member: Whetten, Robert L.
Sönnichsen, Carsten. "Plasmons in metal nanostructures." [S.l.] : [s.n.], 2001. http://edoc.ub.uni-muenchen.de/archive/00002367.
Повний текст джерелаSönnichsen, Carsten. "Plasmons in metal nanostructures." Diss., lmu, 2001. http://nbn-resolving.de/urn:nbn:de:bvb:19-23678.
Повний текст джерелаCheng, Ka Ying. "Nano-metals plasmonic coupling." HKBU Institutional Repository, 2020. https://repository.hkbu.edu.hk/etd_oa/747.
Повний текст джерелаHellström, Staffan. "Exciton-plasmon interactions in metal-semiconductor nanostructures." Doctoral thesis, KTH, Teoretisk kemi och biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-93306.
Повний текст джерелаQC 20120417
Mailhes, Romain. "Effets plasmoniques induits par des nanostructures d’argent sur des couches minces de silicium." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI097/document.
Повний текст джерелаThin-film photovoltaics focus on lowering the cost reduction of photovoltaic energy through the significant reduction of raw materials used. In the case of thin-films crystalline silicon, the reduction of the thickness of the cell is linked to a drastic decrease of the absorption, particularly for the higher wavelengths. This decrease of the absorption can be fought through the use of several different light trapping methods, and the use of plasmonic effects induced by metallic nanostructures is one of them. In this work, we study the influence of a periodic array of silver nanostructures on the absorption of a silicon layer. This work is decomposed into two main axes. First, the influence of the plasmonic effects on the silicon absorption is highlighted through different numerical simulations performed by the FDTD method. Both finite and infinite arrays of silver nanostructures, located at the rear side of a thin silicon layer, are studied. By varying the parameters of the array, we show that the silicon absorption can be improved in the near infrared spectral region, over a wide range of wavelengths. The second part of the thesis is dedicated to the fabrication of such modeled structures. Two different approaches have been explored and developed inside the lab. For each of these two strategies, three major building blocks have been identified: (i) definition of the future array pattern through a mask, (ii) etching of the pattern in the silicon layer and (iii) filling of the pores with silver in order to form the metallic array of nanostructures. In the first fabrication method, an anodic alumina mask, produced by the electrochemical anodization of an aluminium layer, is used in order to define the dimensions of the metallic array. A metal assisted chemical etching is then performed to produce the pores inside the silicon, which will then be filled with silver through a wet chemical process. The second fabrication method developed involves the use of holographic lithography to produce the mask, the pores in silicon are formed by reactive ion etching and they are filled during an electroless silver deposition step. The fabricated plasmonic substrates are optically characterized using an integrating sphere, and transmission, reflection and absorption are measured. All the characterized plasmonic substrates shown a decrease of their reflection and transmission and an absorption enhancement at the largest wavelengths
Kim, Kwang-Hyon. "Ultrafast nonlinear optical processes in metal-dielectric nanocomposites and nanostructures." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2012. http://dx.doi.org/10.18452/16495.
Повний текст джерелаThis work reports results of a theoretical study of nonlinear optical processes in metal-dielectric nanocomposites used for the increase of the nonlinear coefficients and for plasmonic field enhancement. The main results include the study of the transient saturable nonlinearity in dielectric composites doped with metal nanoparticles, its physical mechanism as well its applications in nonlinear optics. For the study of the transient response, a time-depending equation for the dielectric function of the nanocomposite using the semi-classical two-temperature model is derived. By using this approach, we study the transient nonlinear characteristics of these materials in comparison with preceding experimental measurements. The results show that these materials behave as efficient saturable absorbers for passive mode-locking of lasers in the spectral range from the visible to near IR. We present results for the modelocked dynamics in short-wavelength solid-state and semiconductor disk lasers; in this spectral range other efficient saturable absorbers do not exist. We suggest a new mechanism for the realization of slow light phenomenon by using glasses doped with metal nanoparticles in a pump-probe regime near the plasmonic resonance. Furthermore, we study femtosecond plasmon generation by mode-locked surface plasmon polariton lasers with Bragg reflectors and metal-gain-absorber layered structures. In the final part of the thesis, we present results for high-order harmonic generation near a metallic fractal rough surface. The results show a possible reduction of the pump intensities by three orders of magnitudes and two orders of magnitudes higher efficiency compared with preceding experimental results by using bow-tie nanostructures.
Gryczynski, Karol Grzegorz. "Electrostatic Effects in III-V Semiconductor Based Metal-optical Nanostructures." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc115090/.
Повний текст джерелаNesbitt, Nathan Taylor. "Facets and Sharp Edges in Metal Nanostructures for Plasmonics and Electrocatalysis." Thesis, Boston College, 2018. http://hdl.handle.net/2345/bc-ir:108004.
Повний текст джерелаThe nanoscale morphology of metals can enable special functionality in plasmonic and electrochemical devices, with applications in energy conversion and storage, sensors, and computers. In particular, sharp edges on metal nano and microstructures are understood to affect the density of electrons on the metal surface. The associated concentration of electric field can concentrate surface plasmon polaritons (SPPs) and enable waveguiding of the SPPs, as we show in this thesis for sharp ridges along aluminum nanowires. Also important is the presence of facets on the metal structures, which determines the orbitals that electrons occupy on the metal surface. Changes in both the electron density and orbitals can affect the binding of molecules to the metal, which can improve reaction kinetics in catalysis. We demonstrate this on gold dendrite and plate electrocatalysts for CO2 electrolysis. Regarding metal nanostructure fabrication, electrochemical deposition and corrosion have demonstrated promising control over the morphology, including the topography, crystallinity, grain boundaries, and crystal faceting. This is important, because existing methods for metal nanostructure fabrication can only produce a circumscribed assortment of morphologies. In contrast, semiconductors and insulators have many new deposition techniques that produce a wide range of controlled morphologies. Of further appeal, electrochemical techniques are solution-based and typically operate at room temperature and pressure, allowing facile scale-up to industrial production. Here we demonstrate and discuss the mechanisms of two new techniques, which produce the aluminum nanowires and gold dendrites and plates discussed above
Thesis (PhD) — Boston College, 2018
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Physics
Marchesini, Matteo. "Plasmon decay dynamics in hybrid metal/doped-semiconductor nanostructures." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23223/.
Повний текст джерелаWang, Haining. "Novel optical properties of metal nanostructures based on surface plasmons." Doctoral diss., University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5720.
Повний текст джерелаPh.D.
Doctorate
Chemistry
Sciences
Chemistry
Fung, Kin-Hung. "Theoretical study of the plasmonic modes of metal nanoparticle arrays and their optical responses /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202008%20FUNG.
Повний текст джерелаYi, Jue-Min. "Diffraction of single holes through planar and nanostructured metal films." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01018454.
Повний текст джерелаDeeb, Claire. "Optical properties of metal nanostructures as probed by photosenitive molecules." Troyes, 2010. http://www.theses.fr/2010TROY0011.
Повний текст джерелаWhile past research has considered the interaction between metal nanoparticles and photo-sensitive molecules, especially the possibility of initiating nanoscale photopolymerization based on the localized surface plasmons of such particles, this PhD dissertation describes the in-depth characterization and optimization of such interactions that result in nanoscale photopolymerization. The present work demonstrates our ability to use the nanophotopolymerization process to quantitatively map with unprecedented resolution, better than 5 nm, both, the near-field of metallic nanoparticles associated with their localized surface plasmons, and the local electric fields resulting from surface charges density at metal/dielectric interfaces. We will emphasize that a precise characterization of the nanoscale molecular mold of the confined electromagnetic field of metal colloids enabled us to quantify the near-field depth and its enhancement factor. Moreover, a near-field spectrum corresponding to the response of localized surface plasmons of a single metal nanoparticle will be assessed. Additionally, we present nanoscale resolution maps of the spatial distribution of the surface charge density created by the electric field dis-continuity at a non-resonant metal/dielectric interface. Furthermore, this work will prove that the nanoscale photopolymerization approach does not only map the near-field of metal nanoparticles, yet it constitutes, from a more fundamental point of view, a unique opportunity to investigate nanophotochemistry
Morgan, Frances Deirdre. "Optical study of noble metal nanostructured arrays : phase mapping of localized surface plasmon resonances." Thesis, Queen's University Belfast, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709554.
Повний текст джерелаTorrance, David. "Influence of the Local Dielectric Environment and its Spatial Symmetry on Metal Nanoparticle Surface Plasmon Resonances." Honors in the Major Thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1195.
Повний текст джерелаBachelors
Sciences
Physics
Walden, Sarah L. "Nonlinear optical properties of ZnO and ZnO-Au composite nanostructures for nanoscale UV emission." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/114126/9/Sarah_Walden_Thesis.pdf.
Повний текст джерелаDe, Silva Vashista C. "Core-Shell Based Metamaterials: Fabrication Protocol and Optical Properties." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1062904/.
Повний текст джерелаVedraine, Sylvain. "Intégration de nanostructures plasmoniques au sein de dispositifs photovoltaïques organiques : étude numérique et expérimentale." Phd thesis, Aix-Marseille Université, 2012. http://tel.archives-ouvertes.fr/tel-00799088.
Повний текст джерелаEs-Saidi, Soukaina. "Optimisation de la réponse optique de réseaux diffractifs métalliques appliqués à la sécurité des documents." Thesis, Troyes, 2020. http://www.theses.fr/2020TROY0016.
Повний текст джерелаSecurity holograms based on sub-wavelength gratings (SWGs) are increasingly used not only to protect sensitive documents, but also to combat against the reprographic technologies used in counterfeiting.The aim of the present work is to design optical security devices to produce visual and chromatic effects, based on the generation of structural colors, easily recognizable but difficult to counterfeit and compatible with high-tech foil production. To this end, we study the optical response of one and two-dimensional asymmetric SWGs fabricated by laser interferometric lithography and scaled up to larger scales on polymer film using roll-to-roll replication processes. The in-depth physical analysis of the resonance mechanisms generated by metallic and hybrid metal-dielectric SWGs allows to understand and tailor their chromatic response. We also demonstrate that hybrid SWGs open new design perspectives and enhance the quality of the perceived colors. The research evidence presented in this contribution clearly shows that the use of modern optimization tools, prior to fabrication, provides an efficient way to tailor and to optimize the resonant response of diffraction gratings. We demonstrate that the multi-objective approach outperforms single-objective strategies and opens the possibility of increasing the complexity of the diffractive structures used for color reproduction. We emphasize that Artificial Intelligence tools constitute an efficient alternative to the traditional time-consuming electromagnetic methods
Rocha, Tulio Costa Rizuti da. "Nanopartículas metálicas anisotrópicas : mecanismos de formação e aplicações ópticas." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277643.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin
Made available in DSpace on 2018-08-10T04:28:03Z (GMT). No. of bitstreams: 1 Rocha_TulioCostaRizutida_D.pdf: 8952935 bytes, checksum: 2283ed573c4cf94d5cba5aa42d7b2113 (MD5) Previous issue date: 2008
Resumo: Nanopartículas de metais nobres têm atraído uma renovada atenção nos últimos anos devido às novas aplicações científicas e tecnológicas explorando suas propriedades ópticas únicas. No regime nanométrico, é bem conhecido que a resposta óptica de metais, associada aos plásmons de superfície, depende fortemente do tamanho e também da forma. De fato, grande parte das aplicações ópticas de nanopartículas de ouro e prata baseia-se na exploração dos efeitos de forma. Porém, apesar dos esforços realizados, os processos que levam à formação de morfologias anisotrópicas ainda não são bem compreendidos e a formulação de um mecanismo geral ainda é um desafio. Nesse trabalho, foram abordados os mecanismos de formação e crescimento de nanoprismas triangulares de prata produzidos por métodos de síntese coloidal. Uma combinação de diferentes técnicas experimentais foi utilizada para estudar diversos aspectos da síntese fotoquímica, dentre eles, a evolução morfológica, a cinética da reação e a estrutura cristalina das nanopartículas. As sólidas evidências experimentais obtidas associadas a outras observações da literatura foram utilizadas na formulação de um modelo fenomenológico para explicar a formação e crescimento dos nanoprismas de prata em métodos fotoquímicos. Esse modelo baseia-se na influência dos defeitos cristalográficos, que induzem a formação dos nanoprismas nos momentos iniciais da síntese, e na excitação de plásmons de superfície, que ocorre em estágios avançados, sendo responsável pela definição do tamanho final dos nanoprismas. Adicionalmente, cálculos teóricos indicaram que aspectos energéticos podem ter um papel ativo nesse sistema, favorecendo o crescimento dos nanoprismas em relação às nanopartículas esféricas durante os estágios iniciais da síntese. Finalmente, os nanoprismas triangulares de prata produzidos foram aplicados ao estudo de efeitos de intensificação do espalhamento Raman de moléculas. Medidas espectroscópicas de moléculas depositadas na superfície de nanoprismas com diferentes tamanhos foram realizadas e a comparação quantitativa dos resultados indicou a presença de um tamanho ótimo, que é determinado por processos de perda de energia dos plásmons de superfície
Abstract: Noble metal nanoparticles have attracted a recent renewed interest due to the new scientific and technological applications exploiting their unique optical properties. At nanometric scale, it is well known that the optical response of metals, related to the excitation of surface plasmons, strongly depends not only on the size of the particles but also on their shape. Several methodologies to produce silver and gold nanoparticles with different shapes are available in the literature. However, notwithstanding the efforts that have been made, the process that lead to the formation of anisotropic morphologies has not been fully understood yet and a general mechanism is still a challenge. In this work, we address the formation and growth mechanisms of silver triangular nanoprisms produced by photochemical methods. A set of characterization tools was used to study different aspects of the photochemical synthesis, namely, the morphological evolution, the reaction kinetics and the crystalline structure of the nanoprisms. The solid experimental evidences obtained here were used to build a phenomenological model that explains the formation and growth of silver triangular nanoplates in photochemical methods. This model was based on the influence of crystallographic defects, which induce the formation of the nanoprismas in the initial stages of the synthesis, and on the excitation of surface plasmons, which occurs in advanced stages and it is responsible for the definition of the final size of the nanoprismas. Additionally, theoretical calculations indicate that energetics might play an important role in this system, favoring the growth of nanoprismas relative to spheres. Finally, the silver triangular nanoprisms were used to study enhancement effects in the Raman scattering of molecules. We performed spectroscopic measurements for nanoplates with different sizes and the quantitative comparison of the curves indicated the existence of an optimum size that is dictated by surface plasmon energy losses
Doutorado
Física da Matéria Condensada
Doutor em Ciências
Tran, Ngoc Minh. "Applications of nonlinear magneto-photonics at the nanoscale." Thesis, Le Mans, 2018. http://www.theses.fr/2018LEMA1029/document.
Повний текст джерелаOwing to surface and interface sensitivity, the magnetic Second Harmonic Generation (mSHG) represents a useful tool to probe magnetic interfaces and nanostructures. This work investigates the coupling and interaction of the mSHG with electromagnetic waves propagating along the surface. Two types of surface waves have been studied: (i) surface plasmon polaritons (SPP) at surfaces of metallic thin films and multilayers, and (ii) the diffraction anomaly at the surface of periodically arranged metallic nanostructures. To study influence of linear and nonlinear excitation of surface waves on the mSHG, the reflected second harmonic (SH) intensity and the magnetic SH contrast in the transverse magneto-optical geometry were measured as a function of the angle of incidence. The use of different femtosecond light sources in the near-infrared optical range, where the SPP dispersion and damping exhibit significant variations, made it possible to disentangle linear and nonlinear contributions to the excitation of surface waves. In this thesis, it is proven that phase-matching of the mSHG and surface electromagnetic waves can lead to the enhancement of both the SH yield and the nonlinear magneto-optical signal. These results are important for controlling of the nonlinear magneto-optical response and could impact the development of magnetic storage devices, label-free biosensors and nonlinear magneto-optical switches
"(Plasmonic metal core)/(semiconductor shell) nanostructures." 2014. http://library.cuhk.edu.hk/record=b6115287.
Повний текст джерела理解硫化過程有助於更好的控制其表面等離子體特性和結構組成。因此,我分別從實驗和數值模擬兩方面研究了銀納米立方塊在硫化過程中表面等離子體特性及其相應Ag/Ag₂S 核/殼的組成及結構的變化。硫化反應分別在溶液及單顆粒環境下進行。同時,我們應用數值模擬計算揭示硫化過程中表面等離子體特性及模式變化。實驗和數值計算均表明硫化反應首先發生在銀納米立方塊的棱角和頂點。隨著反應的進行,銀立方塊被逐步鈍化為球狀銀納米顆粒。與此同時,納米立方結構的尺寸也隨之小幅增加。
二氧化鈦是一種重要的被應用於光能捕獲的半導體納米材料。因其低毒性、生物兼容性、化學及熱穩定性、耐光腐蝕性以及資源豐富等特點,TiO₂ 已經被廣泛研究。但是TiO₂僅在紫外光區具有光化學活性,這大大限制了其在光能捕獲方面的應用。儘管Au/TiO₂核/殼結構複合物可以提高TiO₂在可見區的光催化活性,但是對於該核/殼結構的合成鮮為報導,而且已報導的工作也是限制在以金納米球作為核層。與金納米球相比,金納米棒具有更引人關注的表面等離子體特性,例如金納米棒具有更高的電場增強,而且金棒的縱向共振波長可以從可見區調控到近紅外區。因此金納米棒/二氧化鈦核/殼結構可以更有效的提高二氧化鈦的光捕獲能力。在此論文中,我發展了一種合成Au/TiO₂核/殼結構的方法,并研究其在光能捕獲方面的應用。在該方法中,我選擇三價鈦作為鈦源,可控合成了Au/TiO₂ 核/殼結構。通過對核的尺寸及殼層厚度的調節,實現了對核/殼結構的共振波長的調控。另外這種方法也適用于其他單組份或者雙組份的鉑、鈀、金納米晶。爲了驗證在光能捕獲方面的應用潛能,Au/TiO₂核/殼結構納米材料被作為散射層而應用於染料敏化太陽能電池中,結果發現這種電池具有較高光電轉化效率。另外,我們還研究了表面等離子體共振激元增強下的活性氧化物的生成。再者,具有較高介電常數的二氧化鈦殼層可以與金納米晶核耦合產生法諾共振效應。結果表明金納米棒的橫向、縱向共振峰均能和殼層材料發生共振耦合而產生對應的法諾效應。納米棒的縱向共振峰的可調性實現了對應的法諾共振峰的可調性。同時,包覆二氧化鈦殼層后,金納米棒的橫向共振模式被大幅放大。
本論文的研究有利於人們了解金屬/半導體納米結構的設計及應用。硫化過程中表面等離子體共振激元特性及結構變化的研究,對具有特定組分及共振特性的複合物的設計合成具有指導意義。對貴金屬/半導體核殼結構製備、共振特性及應用的研究也擴展了其在光能捕獲方面的應用。
Over the past several years, integration of metal nanocrystals that can support localized surface plasmon has been demonstrated as one of the most promising methods to the improvement of the light-harvesting efficiency of semiconductors. Ag and Au nanocrystals have been extensively hybridized with semiconductors by either deposition or anchoring. However, metal nanocrystals tend to aggregate, reshape, detach, or grow into large nanocrystals, leading to a loss of the unique properties seen in the original nanocrystals. Fortunately, core/shell nanostructures, circumventing the aforementioned problems, have been demonstrated to exhibit superior photoactivities.To further improve the light-harvesting applications of (plasmonic metalcore)/(semiconductor shell) nanostructures, it is vital to understand the plasmonic and structural evolutions during the preparation processes, design novel hybridnanostructures, and improve their light-harvesting performances. In this thesis, I therefore studied the plasmonic and structural evolutions during the formation of (Ag core)/(Ag₂S shell) nanostructures. Moreover, I also prepared (noble metal core)/(TiO₂shell) nanostructures and investigated their plasmonic properties and photon-harvesting applications.
Clear understanding of the sulfidation process can enable fine control of the plasmonic properties as well as the structural composition of Ag/Ag₂S nanomaterials.Therefore, I investigated the plasmonic and structural variations during the sulfidation process of Ag nanocubes both experimentally and numerically. The sulfidation reactions were carried out at both the ensemble and single-particle levels.Electrodynamic simulations were also employed to study the variations of theplasmonic properties and plasmon modes. Both experiment and simulation results revealed that sulfidation initiates at the vertices of Ag nanocubes. Ag nanocubes arethen gradually truncated and each nanocube becomes a nanosphere eventually. The cubic shape is maintained throughout the sulfidation process, with the edge lengthii being increased gradually.
TiO₂ is one of the most important semiconductors that are employed inlight-harvesting applications. It has been extensively studied for a variety of applications by virtue of its low toxicity, biological compatibility, chemical and thermal stability, resistance to photocorrosion, and relative abundance. However, the photocatalytic activity of TiO₂ is limited to the UV region because of its wide bandgap, which limits its applications in light harvesting. Although (Au core)/(TiO₂ shell)nanostructures can improve the photocatalytic activities of TiO₂ in visible light, it hasonly been demonstrated in a few experiments and has been limited with Au nanospheres. Compared with Au nanospheres, Au nanorods offer more attractive plasmonic features, including stronger electric field enhancements and synthetically tunable longitudinal plasmon wavelengths over the visible to near-infrared region. The coating of Au nanorod therefore can largely improve light harvesting capabilityof TiO₂. In this thesis, I developed a facile and versatile method for the preparation of(Au nanocrystal core)/(TiO₂ shell) nanostructures by using a Ti(III) compound as thetitania precursor. By employing Au nanorods with different sizes and varying the shellthickness, the plasmonic bands of the core/shell nanostructures can be tailored. TiO₂can also be grown on other monometallic and bimetallic Pd, Pt, Au nanocrystals. As aproof-of-concept application, (Au nanorod core)/(TiO₂ shell) nanostructures wereutilized in dye-sensitized solar cells to function as a scattering layer. The resultantsolar cells exhibited higher power conversion efficiencies with a thinner thickness compared to the traditional TiO₂ solar cells. In addition, I also examined the property of plasmon-enhanced reactive oxygen species generation. Moreover, the TiO₂ shell with a high refractive index can efficiently couple with the plasmon resonance modesof the Au nanorod core, leading to Fano resonances. Fano resonances for both the transverse and longitudinal plasmon modes were simultaneously observed. The longitudinal Fano resonance is tunable by changing the plasmon energy of thenanorod core. In addition, coating with TiO₂ intensifies the transverse plasmon modeof the Au nanorod core.
I believe that my research study will be very helpful for the design and applications of metal/semiconductor nanostructures. The full understanding of the plasmonic and structural evolutions during the preparation processes will be useful for designing metal/semiconductor hybrid nanomaterials with desired compositions and plasmonic properties. The efforts towards the investigations of the preparation, plasmonic properties, and applications of (noble metal core)/(semiconductor shell) nanostructures are important for widening their light-harvesting applications.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Fang, Caihong = 具有表面等離子體激元特性的金屬/半導體核/殼納米結構 / 房彩虹.
Thesis (Ph.D.) Chinese University of Hong Kong, 2014.
Includes bibliographical references.
Abstracts also in Chinese.
Fang, Caihong = Ju you biao mian deng li zi ti ji yuan te xing de jin shu/ban dao ti he/qiao na mi jie gou / Fang Caihong.
Sangita. "Numerical simulation of optical properties of plasmonic metal nanostructures." Thesis, 2017. http://localhost:8080/xmlui/handle/12345678/7456.
Повний текст джерела"Plasmonic Metal/Semiconductor Nanostructures and Mesoporous Metal Phosphide Microspheres for Energy Applications." 2016. http://repository.lib.cuhk.edu.hk/en/item/cuhk-1292679.
Повний текст джерелаSiva, Chandra Sekhar P. "Dye-sensitized and perovskite solar cells performance enhancement using plasmonic metal nanostructures and nanocomposite." Thesis, 2017. http://localhost:8080/xmlui/handle/12345678/7513.
Повний текст джерелаBhardwaj, Shivani. "Plasmonic properties of graphene-metal nanostructures for broad spectral tailoring." Thesis, 2018. http://eprint.iitd.ac.in:80//handle/2074/7946.
Повний текст джерелаZhen, Yurong. "Plasmonic properties and applications of metallic nanostructures." Thesis, 2013. http://hdl.handle.net/1911/72071.
Повний текст джерелаBiring, Sajal, and 畢少強. "Study on Fabrication of Metal Nanostructures by Electrochemical Methods &Their Plasmonic Coupling." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/43995569233047856324.
Повний текст джерела國立清華大學
化學系
96
A rapid electrochemical replication technique is developed to fabricate ultra-smooth aluminum foils by exploiting readily available large-scale smooth silicon wafer as the master. Since the adhesion of aluminum on silicon depends on the time of surface pretreatment in water, it is possible to either detach the replicated aluminum from the silicon master without damaging the replicated aluminum and master or integrate the aluminum film to the silicon substrate. Replicated ultra-smooth aluminum foils are used for the growth of both self-organized and lithographically guided long-range ordered arrays of anodic alumina nanochannels without any polishing pre-treatment. An electrochemical nanomolding technique for the large-scale and rapid fabrication of metallic nanostructures has been demonstrated taking advantage of the above method. Here, Nanostructures with features down to 10 nm has been fabricated by fast electrochemical deposition of aluminum on nanopatterned silicon mold followed by mechanical peeling off the aluminum foil from the mold. This high fidelity, non-destructive technique can exploit the mold for repeated use in mass production of nanostructures and also opens up new possibilities in the field of nano-scale design and fabrication. Finally, a large-scale guiding technique has been presented to fabricate long-range order anodic alumina nanochannel arrays based on electrochemical nanomolding. Optical properties of metal nanostructures grown inside the anodic alumina nanochannels have been studied thoroughly. Electromagnetic interactions of the near-, intermediate- and far-zone in an array of metallic nanoparticles are responsible for many of its anomalous plasmonic properties. While this so-called plasmonic coupling has become a focus of many researches lately, its interaction mechanisms still remain concealed, mainly due to the lack of spectroscopic observations from precisely fabricated samples as well as analytical interpretations. Here, I present light scattering spectra of arrays of silver nanoparticles with gaps of sub-10 nm precision, which are fabricated based on the unique self-organizing property of porous alumina templates. I show that their near- and immediate-zone interactions are manifested in the spectra through analytical formulae derived from first principle. The findings provide a profound base to predict unexplored plasmonic properties such as the relationship between the Q factor of the arrays and their structural characteristics. The results are instrumental in the development of extended plasmonic nanostructures, such as surface-enhanced Raman substrates. In a very lucid way, I have also studied the particle plasmon resonace behavior using light scattering spectroscopy in a binary dielectric media where silver nano-rods are embedded partially in Anodic Aluminum Oxide (AAO) matrix and in air. Here I did a systematic experimental study under a controlled variation of the degree of embedding of nano-rods in AAO matrix. I used Finite Difference Time Domain (FDTD) method to calculate the nature of the silver nano-rod resonance at the experimental conditions. The results have been interpreted based on the Drude model.
Hsieh, Kai-Ting, and 謝凱婷. "Synthesis of porous metal nanoparticles and plasmonic nanostructures for surface-enhanced Raman spectroscopy (SERS)." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/94105380513386953608.
Повний текст джерела國立陽明大學
生醫光電研究所
105
In recent years, various SERS substrates have been developed and applied to the detection of molecules, but fabricating a highly reproductive, simple, and cost effective SERS nanostructure with a significant Raman enhancement is still challenging. In this study, we successfully synthesized two different SERS structures. For first structure, we applied a self-assembly method to immobilize the gold nanoparticles (AuNPs) on a silica beads to form the core-satellite nanostructure, which contained 3D SERS hot spots. Then, we covered the immobilized AuNPs with silver shells to regulate the inter-particle distance to optimize the SERS effects. Furthermore, we accumulated the particles with the nanostructure on filter paper as SERS substrates for SERS detection of malachite green, and then we successfully did SERS detection of malachite green with detection limit of 50 fM. Moreover, we applied fluidic system to detect two different molecules; malachite green and sodium thiocyanate. For the other nanostructure, we used dealloying process to acquire highly porous Au−Ag alloy nanoparticles covered with ultrathin silica shells. These Au−Ag alloy nanoparticles contained more SERS hot spots, and the nanoparticles were more stable and clean on surface in solutions. For the measurement, we accumulated the porous nanoparticles on filter paper as SERS substrates, and we performed SERS detection of adenine.
Zhao, Lan. "Shaping the near-field with resonant metal nanostructures." Thesis, 2012. http://hdl.handle.net/1828/3925.
Повний текст джерелаGraduate
"Plasmonic spectroscopy of metallic nanostructures." Thesis, 2008. http://library.cuhk.edu.hk/record=b6074627.
Повний текст джерелаI will first describe my studies on the plasmonic properties of metallic nanostructures. Specific approaches of modifying the sizes and shapes of Au nanorods have been developed for tailoring their plasmonic properties, including surface plasmon wavelength, absorption, scattering, and extinction cross sections. Single-particle dark-field imaging and spectroscopy have proved that the scattering intensity of overgrown nanorods is larger than that of shortened nanorods from the same starting nanorods. Finite-difference time-domain (FDTD) calculations further show that the scattering-to-extinction ratio increases linearly as a function of the diameter of Au nanorods with a fixed aspect ratio. To obtain a deep understanding on the shape dependence of the localized surface plasmon resonance, I have emplyed FDTD on both Au nanorods and Au nanobipyramids. The results show that, when excited at their LSP wavelengths, Au nanobipyramids exhibit a maximal electric field intensity enhancement that is 3--6 times that of Au nanorods. Au nanorods have been further assembled into chains (end-to-end) and stacks (side-by-side). FDTD calculations have been performed on both Au nanorod chains and stacks with varying gap distances to obtain the dependence of the plasmon shift on the gap distance, which is then used as a plasmonic ruler to estimate the gap distance between assembled nanorods. Moreover, dye--Au nanorod hybrid nanostructures have also been successfully fabricated for the study of the coupling between the transition dipole resonance and the plasmonic resonance. The coupling-induced plasmon shift is found to be strongly dependent on molecular properties, the dye concentration in solutions, and the spacer thickness between dye molecules and the surface of Au nanorods. The coupling can be switched off by means of laser-induced photodecomposition of dye molecules.
Next, I will present my studies on the applications of metallic nanostructures. A SERS substrate has been constructed by assembling silver nanoparticles along silica nanofibers. The enhancement factors are found to be 2 x 10 5 for 4-mercaptobenzoic acid and 4-mercaptophenol, and 7 x 10 7 for rhodamine B isothiocyanate. A novel plasmonic optical fiber device has further been fabricated to detect small changes in the local dielectric environment. For individual Au nanorods, the index sensitivity and figure of merit (FOM) are found to be linearly dependent on the longitudinal plasmon resonance wavelength and reach 200 nm/RIU and 3.8, respectively. For nanorod ensembles, the index sensitivity and FOM of the longitudinal plasmon resonance are found to be 138 nm/RIU and 1.2, respectively.
The study of the plasmonic spectroscopy of metallic nanostructures is of great interest in nanoscale optics and photonics. Metallic nanostructures exhibit rich optical and electrical properties due to their localized surface plasmons (LSPs, collective charge density oscillations that are confined to metallic nanostructures). They can be widely used in a variety of application areas, such as surface-enhanced Raman scattering (SERS), plasmonic sensing, and metal enhanced fluorescence (MEF). In this thesis, a systematic study on the plasmonic spectroscopy of metallic nanostructures has been presented, both theoretically and experimentally.
Ni, Wei hai = 金屬納米結構的等離子體光譜 / 倪衛海.
Adviser: Jianfang Wang.
Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3580.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2008.
Includes bibliographical references (leaves 135-154).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstracts in English and Chinese.
School code: 1307.
Ni, Wei hai = Jin shu na mi jie gou de deng li zi ti guang pu / Ni Weihai.
Sönnichsen, Carsten [Verfasser]. "Plasmons in metal nanostructures / vorgelegt von Carsten Sönnichsen." 2001. http://d-nb.info/972019901/34.
Повний текст джерелаWang, Yikuan. "Exciton-plasmon interactions in hybrid metal-semiconductor nanostructures." 2009. https://scholarworks.umass.edu/dissertations/AAI3380038.
Повний текст джерелаRatchford, Daniel Cole. "Manipulating fluorescence dynamics in semiconductor quantum dots and metal nanostructures." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-12-4712.
Повний текст джерелаtext
Chang, Chieh-Feng. "Wafer-Scalable Fabrication of Metal Nanostructures for Plasmonics-Assisted Biomedical Sensing Applications." Thesis, 2015. https://thesis.library.caltech.edu/8965/7/CFC_Thesis_2015-revised.pdf.
Повний текст джерелаPlasmonics provides many opportunities of sensing and detection since it combines the nanoscale spatial confinement and the optical temporal resolution. The wireless nature of photonic investigation, moreover, is very desirable for biomedical applications. Plasmonic metals, however, are difficult to pattern with great nanoscopic precision, and traditional approaches were time-consuming, non-scalable, stochastically-manufactured, or highly-limiting in the pattern designs. In this work, wafer-scalable nanofabrication methods are presented for various plasmonic structures for biomedical sensing applications. The fabrication steps have ready counterparts in commercial semiconductor foundries and therefore can be directly applied for mass production.
The fabrication and measurement of extraordinary transmission (EOT) are discussed in Chapter 2. Fabrication options are available for substrates like silicon-on-sapphire and silicon-on-glass, so that the devices can be mechanically robust for user-friendliness. The metal layer can also be varied for EOT applications in different ranges of wavelengths. The EOT nanostructures can be fabricated to be polarization-sensitive, and the concept of fluorescence-based EOT assays is demonstrated.
The fabrication and applications of surface-enhanced Raman spectroscopy (SERS) are then discussed. With a hybrid approach, the top-down designing defines uniform SERS nanostructures on a chip, while the bottom-up process of thermal reflow increases the fabrication precision beyond the lithography resolution limit. Based on the thiophenol study, an enhancement factor greater than 1010 can be achieved. The first Raman spectrum of tracheal cytotoxin is demonstrated without any special sample preparation, and thrombin binding could be easily resolved through chip functionalization. The binding dynamics of ethyl mercaptan, which is similar to the highly toxic gas of hydrogen sulfide, can be detected with a good resolution in time at a low concentration.
With a few more steps of fabrication, the plasmonic structures can be integrated into systems that do not call for laboratory infrastructures. A built-in micro-channel on a chip can make the device useful without dedicated support of a microscope or additional microfluidic structures. The nanostructures can also be transferred onto flexible substrates for better conformity onto various surfaces. Finally, the SERS structures can be transferred onto a fiber tip for in-field or through-the-needle applications, especially when combined with a portable Raman-scope.
"Plasmon hybridization in real metals." Thesis, 2012. http://hdl.handle.net/1911/70207.
Повний текст джерела(9137693), Bruce Zhang. "INTEGRATION OF FERROMAGNETIC METALS IN VERTICALLY ALIGNED NANOSTRUCTURES FOR SPINTRONICS." Thesis, 2020.
Знайти повний текст джерелаVertically aligned nanocomposite (VAN) thin films are a promising thin-film platform that allows the combination of a highly desired material with another complementary oxide. Traditionally, VANs have been limited to combining an oxide with another oxide which has shown a wide range of functionality, and, by adjusting the different growth parameters, it has led to the tuning of their physical properties. While VANs have already shown to be an effective platform with immense potential, further enhancement of physical properties can be performed by replacing one of the oxides with a metal forming metal-oxide VANs.
In this dissertation, by the inclusion of the 3d transition metals, e.g., Fe and Co, into various oxide matrices, such as La0.5Sr0.5FeO3, BaZrO3, and BaTiO3, strong, highly anisotropic, ferromagnetic properties have been achieved. By varying the growth parameters, tunable physical properties, mainly coercivity and anisotropic ratio, have been demonstrated. Furthermore, in the case of Co-BaZrO3, a multi-layer stack has been successfully grown and demonstrated a tailorable magnetoresistance. Additionally, a novel system by combining Fe pillars into a BaTiO3 matrix has been demonstrated. This new system allows for the combination of the room temperature Fe ferromagnetic properties with the ferroelectric properties of BaTiO3, allowing for coupling between the two with coercivity tuning and tailorable ferromagnetic properties.
Lastly, it has been shown a possible framework by adding additional metals into the existing metal-oxide VAN platform. By adding the third phase, another metal, it opens up a new avenue to induce additional functionality while creating a method to introduce coupling between the different metals and physical properties.
(5930936), Xiaohui Xu. "Investigation of Energetic Materials and Plasmonic Nanostructures Using Advanced Electron Microscopic Techniques." Thesis, 2019.
Знайти повний текст джерелаInvestigation of laser-matter interaction has been an important research topic which is closely related to applications in various fields including industry, military, electronics, photonics, etc. With the advent of ultrafast transmission electron microscope (UTEM), in situ investigation of the interaction between pulsed laser and nanostructured materials becomes accessible, with unprecedented spatial and temporal resolution. Here, we studied two categories of materials with the help of UTEM, namely, energetic materials and plasmonic nanostructures. The results demonstrate that UTEM provides a novel and convenient way for the investigation the structural and morphological change of energetic materials under external stimuli at nanoscale. Also, UTEM makes it possible to visualize the light-induced welding between plasmonic nanostructures at real time, which helps to reveal more details about the mechanisms involved. Furthermore, we studied the formation of some novel structures by combing different gold and silver nanostructure.
Silva, Solange Vieira da. "Trapping light in metal and topological nanostructures." Doctoral thesis, 2020. http://hdl.handle.net/10316/96362.
Повний текст джерелаNanophotonics is a field of research dedicated to study the interactions of nanosized-objects with light. One of the goals of nanophotonics is to enable the miniaturization of optical components at a competitive scale with microelectronics. There are several rewards in using light based technologies, such as building photonic circuits that are not only smaller but faster and more efficient than the electronic counterparts, new solar cells that have enhanced energy absorption, nano-optical sensors able to detect ultralow concentrations of molecules in chemical solutions, amongst many others. My work aims to contribute to this field of research by exploring new mechanisms to accomplish an efficient spatial confinement of light. This thesis is devoted to the analytical and numerical study of three different ways to confine light in the nanoscale. First, we investigate light trapping in open plasmonic resonators (metaatoms) with different shapes. It is found that in some conditions complexshaped dielectric cavities may support discrete light states screened by volume plasmons that in the limit of a vanishing material loss have an infinite lifetime. The embedded eigenstates can be efficiently pumped with a plane wave excitation when the meta-atom core has a nonlinear response, such that the trapped light energy is precisely quantized. Then, we investigate how the spatial dispersion effects, e.g., caused by the electron-electron interactions in a metal, affect these trapped eigenstates in three-dimensional open plasmonic resonators. Heuristically, one may expect that the repulsive-type electron-electron interactions should act against light localization, and thereby that they should have a negative impact on the formation of the embedded eigenstates. Surprisingly, it is found that the nonlocality of the material response creates new degrees of freedom and relaxes the requirements for the observation of trapped light. In particular, a zero-permittivity condition is no longer mandatory and the same resonator shell can potentially suppress the radiation loss at multiple frequencies. The possibility to trap and guide light in wire metamaterials is also investigated. Specifically, we investigate the guided modes supported by a metamaterial slab formed by two mutually orthogonal and nonconnected sets of parallel metallic wires. It is demonstrated that the wire medium slab has a peculiar comb-like dispersion diagram. In the continuum approximation, the metamaterial supports a diverging number of guided mode branches that accumulate near the light line due to a strong hyperbolic response in the static limit. In a realistic system, the number of guided modes branches is finite and is determined by the density of wires. Remarkably, the guided modes may be characterized by a fast field variation along the transverse direction, which can be exploited to detect subwavelength particles or defects. Lastly, we investigated topological trapped states in photonic crystals. We show that in one-dimensional periodic systems the number of bands below a band gap determines the topological Chern number of an extended system with a synthetic dimension. It is theoretically and numerically demonstrated that in real-space the Chern number gives the number of gapless trapped state branches localized at the interface of the photonic crystal, when its geometry is continuously displaced by one lattice period. Furthermore, we introduce a novel class of topological systems with inversion-symmetry and fractional (non-integral) Chern numbers. It is proven that the non-integral topological number arises due to the discontinuous behaviour of the Hamiltonian in the spectral domain. We introduce a bulk-edge correspondence that links the number of edge-states with the fractional topological number.
A nano-fotónica é uma área de investigação dedicada ao estudo das interacções da luz com objectos nanométricos. Um dos objectivos da nanofotónica é possibilitar a miniaturização de componentes ópticos para uma escala competitiva com a microelectrónica. Existem vários benefícios em usar tecnologia fotónica, como a construção de circuitos fotónicos com pequenas dimensões que não são apenas mais rápidos mas também mais eficientes do que as suas contrapartes eletrónicas, novas células solares com uma maior absorção energética, sensores nano-ópticos capazes de detectar concentrações extremamente baixas de moléculas em soluções químicas, entre outros. O objectivo principal do meu trabalho é contribuir para esta área de investigação, explorando novos mecanismos de confinamento espacial da luz de forma eficiente. Esta tese é dedicada ao estudo analítico e numérico de três mecanismos diferentes de confinar a luz à nano-escala. Em primeiro lugar, é investigado o aprisionamento da luz em ressoadores plasmónicos abertos (meta-átomos) de diferentes geometrias. É mostrado que, em certas condições, cavidades dieléctricas de geometrias complexas podem suportar estado fotónicos discretos que, no limite em que as perdas materiais são nulas, possuem tempos de vida infinitos. Estes estados surgem devido à acção dos plasmões de volume suportados pela camada plasmónica exterior do meta-átomo e podem ser excitados eficientemente por uma onda plana quando o núcleo do ressoador possui uma resposta não-linear. Demonstra-se que a energia aprisionada no núcleo do ressoador é precisamente quantizada. Depois, é investigado o impacto dos efeitos de dispersão espacial, causados por exemplo pelas interacções electrão-electrão em metais, nos estados próprios embebidos suportados por ressoadores abertos plasmónicos tridimensionais. Heuristicamente, seria de esperar que as interacções repulsivas electrão-electrão agissem de maneira deteriorante no mecanismo de localização de luz e, portanto, tivessem um impacto negativo na formação dos estados próprios embebidos. Surpreendentemente, é mostrado neste trabalho que a dispersão não-local do material que encapsula o meta-átomo dá origem a novos graus de liberdade e relaxa os requisitos necessários ao aprisionamento da luz. Em particular, a condição que exige que o material da cápsula exiba uma permitividade exactamente igual a zero deixa de ser obrigatória, passando a ser possível que a mesma cápsula suprima a perda por radiação em várias frequências. É estudada de seguida a possibilidade de aprisionar e guiar luz em metamateriais de fios metálicos. Especificamente, investigamos os modos guiados suportados por um metamaterial formado por dois planos de fios metálicos mutuamente ortogonais. É demonstrado que o meio de fios tem um diagrama de dispersão peculiar, semelhante a um pente. No limite em que o material é visto como um meio contínuo (homogeneizado), o metamaterial suporta um número divergente de “ramos” de modos guiados que se acumulam junto à linha da luz devido à forte resposta hiperbólica do metamaterial no limite estático. Num sistema realista, o número de ramos é finito e determinado pela densidade de fios. Curiosamente, os modos são caracterizados por uma variação do campo rápida na direcção transversal, que pode ser explorada na detecção de partículas e defeitos de dimensão sub-lambda. Por último, são investigados modos de luz topologicamente aprisionados em cristais fotónicos. São estudadas as propriedades topológicas de sistemas periódicos unidimensionais, e é mostrado que o número de bandas abaixo do hiato de frequências determina o número de Chern de um sistema extendido com uma dimensão sintética. É demonstrado teórica e numericamente que, no espaço-real, o número de Chern determina o número de estados aprisionados na interface de um cristal fotónico no intervalo de frequências da banda não-propagante, quando a sua geometria sofre uma deslocação contínua de um período de estrutura. Além disso, é introduzida uma nova classe de sistemas topológicos com inversão de simetria e números de Chern fraccionários. É provado que o número topológico fraccionário é devido às descontinuidades do Hamiltoniano no domínio espectral. É introduzida uma correspondência volume-interface que liga o número de estados de interface com o número topológico fraccionário.
Instituto de Telecomunicações
Huang, Jhih-Bin, and 黃志濱. "Study of Surface Plasmon Resonance in Hetero-Metal Nanostructures and Their Detection Sensitivities." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/68628785638431183763.
Повний текст джерела國立臺灣海洋大學
機械與機電工程學系
100
Nanostructure-based surface plasmon resonance sensors are capable of sensitive and label-free detection for biomedical applications. However, nanostructures with higher sensitivities and high-throughput, low-cost fabrication techniques are the main issues which should be addressed. In this thesis, we utilized three kinds of methods, thermal-annealing-assisted template stripping, and template-stripping with UV gel and nanoimprinting, to fabricate bi-layer metallic grating structures, which fulfills the mentioned requirements. We studied the effect of the structure parameters of bi-layer gold grating structures and bi-layer Al/Au bimetallic grating structures on refractive index sensitivity. The bi-layer grating structures with a 500 nm period, various slit widths, from 60 to 180 nm, and various metal thicknesses, from 50 to 100 nm, were made. We found that a transverse magnetic-polarized wave in these gold nanostructures generated sharp and asymmetric Fano resonances in transmission spectra. The full width at half-maximum bandwidth decreased with the decrease of the slit width, the decrease of the ratio of gold film in hetero Al-Au film, the increase of metal thickness and the decrease of the distance between layers. The narrowest bandwidth was 6 nm. Compared to single-layer nanoslit arrays, the proposed structure has a similar wavelength sensitivity but narrower bandwidth. In addition, it has a higher intensity sensitivity up to 33344 %/RIU and reaches a figure of merit up to 103.5. The current structure can achieve a detection limit of 5.99 × 10-6 RIU when the intensity resolution is 0.2%. We furtherconducted an antigen-antibody interaction experiment in aqueous environment to verify the detection sensitivity in surface binding event.
Parashar, Piyush Kumar. "Plasmonic silicon solar cells : influence of metal and hybrid nanostructured layers on opto-electronic properties on the device." Thesis, 2018. http://localhost:8080/xmlui/handle/12345678/7571.
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