Observing Plasmonic−Molecular Resonance Coupling on Single Gold Nanorods

Ni, Weihai; Ambjörnsson, Tobias; Apell, S. Peter; Chen, Huanjun; Wang, Jianfang

doi:10.1021/nl902851b

Cited by 184 publications

(218 citation statements)

References 30 publications

(92 reference statements)

Supporting

Mentioning

212

Contrasting

Order By: Relevance

“…1 a general description of the problem, using Mie theory to model the optical response of silver colloids, and a standard isotropic effective medium [22,25,27,30,31,33,35,36] for the thin coating layer arXiv:1509.07216v1 [physics.optics]…”

Section: Predictions From Electromagnetic Theorymentioning

confidence: 99%

“…Many of these existing and emerging applications are underpinned by the fact that the optical (electronic) absorption of molecules on the surface of metallic NPs is enhanced. But spectral changes induced by molecular adsorption are often ignored because of the experimental challenge of measuring surface absorbance spectra on nanoparticles, despite early attempts more than 30 years ago [21].This question is not directly addressed in the great number of recent studies devoted to the topic of strongcoupling between plasmons and molecules [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]; in this regime, the plasmon-molecule interaction is evidenced by a typical anti-crossing of the two resonances as a function of detuning [25,33], but in such a strongly interacting system the molecular response cannot be isolated. Moreover, in such studies the dye concentration is often large (typically monolayer coverage and above) to maximize dye/plasmon interactions.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Modified optical absorption of molecules on metallic nanoparticles at sub-monolayer coverage

Darby¹,

Auguié²,

Meyer³

et al. 2015

Nature Photon

138

192

View full text Add to dashboard Cite

Enhanced optical absorption of molecules in the vicinity of metallic nanostructures is key to a number of surface-enhanced spectroscopies and of great general interest to the fields of plasmonics and nano-optics. Yet, experimental access to this absorbance has long proven elusive. We here present direct measurements of the intrinsic absorbance of dye-molecules adsorbed onto silver nanospheres, and crucially, at sub-monolayer concentrations where dye-dye interactions become negligible. With a large detuning from the plasmon resonance, distinct shifts and broadening of the molecular resonances reveal the intrinsic properties of the dye in contact with the metal colloid, in contrast to the often studied strong-coupling regime where the optical properties of the dye-molecules cannot be isolated. The observation of these shifts together with the ability to routinely measure them has broad implications in the interpretation of experiments involving resonant molecules on metallic surfaces, such as surface-enhanced spectroscopies and many aspects of molecular plasmonics.Over the last two decades, the optical properties of metallic nanoparticles (NPs) of various sizes and shapes [1] [18][19][20]. Many of these existing and emerging applications are underpinned by the fact that the optical (electronic) absorption of molecules on the surface of metallic NPs is enhanced. But spectral changes induced by molecular adsorption are often ignored because of the experimental challenge of measuring surface absorbance spectra on nanoparticles, despite early attempts more than 30 years ago [21].This question is not directly addressed in the great number of recent studies devoted to the topic of strongcoupling between plasmons and molecules [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]; in this regime, the plasmon-molecule interaction is evidenced by a typical anti-crossing of the two resonances as a function of detuning [25,33], but in such a strongly interacting system the molecular response cannot be isolated. Moreover, in such studies the dye concentration is often large (typically monolayer coverage and above) to maximize dye/plasmon interactions. Dye-dye interactions cannot therefore be neglected and are expected to induce resonance shifts of the dye layer independently of any plas- * Eric.LeRu@vuw.ac.nz monic effects; in fact many studies specifically work with J-aggregates rather than isolated dyes [22, 25-27, 31, 33]. As a result, the intrinsic effect (chemical and/or electromagnetic) of the NP on an isolated adsorbed molecule cannot be elucidated. To this aim, we will show that it is necessary to measure the absorbance of the dye when the dye and plasmon resonances are detuned (to avoid dye-plasmon interaction effects) and at low surface coverage (to avoid dye-dye interaction effects). This low surface coverage poses a significant experimental challenge because the dye absorbance is then very small and obscured by the large optical response (absorption and scattering) of the NPs.We here propose to measure NP/d...

show abstract

Section: Predictions From Electromagnetic Theorymentioning

confidence: 99%

mentioning

confidence: 99%

Modified optical absorption of molecules on metallic nanoparticles at sub-monolayer coverage

Darby¹,

Auguié²,

Meyer³

et al. 2015

Nature Photon

138

192

View full text Add to dashboard Cite

show abstract

“…Recently several groups have moved to a much smaller scale, investigating strong interaction of molecular excitons with individual plasmonic resonators, such as metallic nanospheres [27,28], nanorods [29][30][31], nanoprisms [15] and nanodisk dimers [13]. This greatly enlarges the freedom to observe and control the strong coupling process at the nanoscale, significantly deepening our understanding of relevant phenomena.…”

mentioning

confidence: 99%

Mode Modification of Plasmonic Gap Resonances Induced by Strong Coupling with Molecular Excitons

Chen

Qin

et al. 2017

Nano Lett.

View full text Add to dashboard Cite

Plasmonic cavities can be used to control the atom-photon coupling process at the nanoscale, since they provide ultrahigh density of optical states in an exceptionally small mode volume. Here we demonstrate strong coupling between molecular excitons and plasmonic resonances (so-called plexcitonic coupling) in a film-coupled nanocube cavity, which can induce profound and significant spectral and spatial modifications to the plasmonic gap modes. Within the spectral span of a single gap mode in the nanotube-film cavity with a 3-nm wide gap, the introduction of narrow-band J-aggregate dye molecules not only enables an anti-crossing behavior in the spectral response, but also splits the single spatial mode into two distinct modes that are easily identified by their far-field scattering profiles. Simulation results confirm the experimental findings and the sensitivity of the plexcitonic coupling is explored using digital control of the gap spacing. Our work opens up a new perspective to study the strong coupling process, greatly extending the functionality of nanophotonic systems, with the potential to be applied in cavity quantum electrodynamic systems. † These authors contributed equally to this work 2 Strong light-matter interactions build upon fast energy exchange [1] between excitonic quantum emitters and electromagnetic (EM) modes in a cavity, which leads to cavity-exciton mode hybridization, manifesting as a split in the cavity spectral response, known as vacuum Rabi splitting.Understanding these phenomena is very important for cavity quantum electrodynamics applications [2,3]; for example, quantum computing requires repeated manipulation of excitonic states with photons before atomic or molecular excitons lose their coherence. On the other hand, once strongly coupled to a resonant cavity, electronic states of molecules can be greatly reshaped [4] from those in free space, enabling a variety of extraordinary effects, such as modification of molecular thermodynamics [5] and chemical landscape [6], mediation of energy transfer between multiple molecules [7] and even alternation of photosynthetic processes in bacteria [8].Strong coupling (SC) requires a high atomic cooperativity (, where g is the coupling strength, γ and κ are the spectral width of the excitonic transition of emitters and EM modes respectively. To achieve high C, traditional investigations [9][10][11][12] have used cavities with high Q performance (quality factor κ ω / = Q , where ω is the oscillation frequency of the cavity).Another solution is to reduce the cavity mode volume V, sincewhere N is the number of excitons contributing to the coupling process. In this context, plasmonic cavities have been proposed to investigate strong coupling, because these cavities can concentrate light energy within deep subwavelength volumes, and thus are capable of providing high cooperativity by compensating their moderate Q values with ultra-small V [13][14][15]. Specifically, plasmonic cavities are specially designed metallic nanostructures, in w...

show abstract

“…29−32 With increasing plasmon−exciton coupling strength, when the excitation energy of the emitter is tuned across the plasmon resonance, the Fano profiles in the scattering cross section evolve into the spectral features of avoided crossings 13,14,19,20 with well-resolved mixed states, so-called plexcitons. 21−23 As demonstrated in recent experiments, 23 the near-field enhancement in the junction between nanoparticles 3−5,33 might lead in this system to the strong plasmon−exciton coupling with large Rabi splitting of the issuing plexcitonic states.…”

mentioning

confidence: 99%

Plexciton Quenching by Resonant Electron Transfer from Quantum Emitter to Metallic Nanoantenna

et al. 2013

View full text Add to dashboard Cite

Coupling molecular excitons and localized surface plasmons in hybrid nanostructures leads to appealing, tunable optical properties. In this respect, the knowledge about the excitation dynamics of a quantum emitter close to a plasmonic nanoantenna is of importance from fundamental and practical points of view. We address here the effect of the excited electron tunneling from the emitter into a metallic nanoparticle(s) in the optical response. When close to a plasmonic nanoparticle, the excited state localized on a quantum emitter becomes short-lived because of the electronic coupling with metal conduction band states. We show that as a consequence, the characteristic features associated with the quantum emitter disappear from the optical absorption spectrum. Thus, for the hybrid nanostructure studied here and comprising quantum emitter in the narrow gap of a plasmonic dimer nanoantenna, the quantum tunneling might quench the plexcitonic states. Under certain conditions the optical response of the system approaches that of the individual plasmonic dimer. Excitation decay via resonant electron transfer can play an important role in many situations of interest such as in surface-enhanced spectroscopies, photovoltaics, catalysis, or quantum information, among others. KEYWORDS: Plexcitons, plasmon, exciton, quantum plasmonics, individual hybrid nanostructures B ringing together metallic nanostructures and quantum emitters, such as quantum dots and molecular complexes, offers unprecedented opportunities in controlling light on the nanoscale. Indeed, the tunability of the plasmonic response and of the near field enhancement in metal nanoparticle assemblies 1−5 allows to engineer the coupling between the excitonic resonance of a quantum emitter (QE) and the collective motion of the metallic electrons, i.e. the plasmons. During the past decade, the study of the interaction between light and these hybrid structures turned into an active field of research 6−25 owing to its fundamental interest and similarity with cavity quantum electrodynamics, 13,19 and due to the vast range of possible applications such as sensing, 26 single photon emitters for information technology, 27,28 and active devices.29−32 With increasing plasmon−exciton coupling strength, when the excitation energy of the emitter is tuned across the plasmon resonance, the Fano profiles in the scattering cross section evolve into the spectral features of avoided crossings 13,14,19,20 with well-resolved mixed states, so-called plexcitons. 21−23 As demonstrated in recent experiments, 23 the near-field enhancement in the junction between nanoparticles 3−5,33 might lead in this system to the strong plasmon−exciton coupling with large Rabi splitting of the issuing plexcitonic states. On the theoretical side, classical and quantum calculations for a QE placed in the middle of the junction of a plasmonic dimer show that the hybrid structure undergoes dramatic changes in the absorption cross section as compared to individual components. [12][13][14][15]23 Thus...

show abstract

Observing Plasmonic−Molecular Resonance Coupling on Single Gold Nanorods

Cited by 184 publications

References 30 publications

Modified optical absorption of molecules on metallic nanoparticles at sub-monolayer coverage

Modified optical absorption of molecules on metallic nanoparticles at sub-monolayer coverage

Mode Modification of Plasmonic Gap Resonances Induced by Strong Coupling with Molecular Excitons

Plexciton Quenching by Resonant Electron Transfer from Quantum Emitter to Metallic Nanoantenna

Contact Info

Product

Resources

About