In this review we look at the concepts and state-of-the-art concerning the strong coupling of surface plasmon-polariton modes to states associated with quantum emitters such as excitons in ...J-aggregates, dye molecules and quantum dots. We explore the phenomenon of strong coupling with reference to a number of examples involving electromagnetic fields and matter. We then provide a concise description of the relevant background physics of surface plasmon polaritons. An extensive overview of the historical background and a detailed discussion of more recent relevant experimental advances concerning strong coupling between surface plasmon polaritons and quantum emitters is then presented. Three conceptual frameworks are then discussed and compared in depth: classical, semi-classical and fully quantum mechanical; these theoretical frameworks will have relevance to strong coupling beyond that involving surface plasmon polaritons. We conclude our review with a perspective on the future of this rapidly emerging field, one we are sure will grow to encompass more intriguing physics and will develop in scope to be of relevance to other areas of science.
When metal nanoparticles are arranged in an ordered array, they may scatter light to produce diffracted waves. If one of the diffracted waves then propagates in the plane of the array, it may couple ...the localized plasmon resonances associated with individual nanoparticles together, leading to an exciting phenomenon, the drastic narrowing of plasmon resonances, down to 1–2 nm in spectral width. This presents a dramatic improvement compared to a typical single particle resonance line width of >80 nm. The very high quality factors of these diffractively coupled plasmon resonances, often referred to as plasmonic surface lattice resonances, and related effects have made this topic a very active and exciting field for fundamental research, and increasingly, these resonances have been investigated for their potential in the development of practical devices for communications, optoelectronics, photovoltaics, data storage, biosensing, and other applications. In the present review article, we describe the basic physical principles and properties of plasmonic surface lattice resonances: the width and quality of the resonances, singularities of the light phase, electric field enhancement, etc. We pay special attention to the conditions of their excitation in different experimental architectures by considering the following: in-plane and out-of-plane polarizations of the incident light, symmetric and asymmetric optical (refractive index) environments, the presence of substrate conductivity, and the presence of an active or magnetic medium. Finally, we review recent progress in applications of plasmonic surface lattice resonances in various fields.
Coupled surface plasmon polaritons (SPPs) are shown to provide effective transfer of excitation energy from donor molecules to acceptor molecules on opposite sides of metal films up to 120 nanometers ...thick. This variant of radiative transfer should allow directional control over the flow of excitation energy with the use of suitably designed metallic nanostructures, with SPPs mediating transfer over length scales of$10^{-7} to 10^{-4}$meters. In the emerging field of nanophotonics, such a prospect could allow subwavelength-scale manipulation of light and provide an interface to the outside world.
Plasmonic Materials Murray, W. A.; Barnes, W. L.
Advanced materials (Weinheim),
11/2007, Letnik:
19, Številka:
22
Journal Article
Recenzirano
We provide an overview of the way in which different approaches to nanostructuring metals can lead to a wealth of interesting optical properties and functionality through manipulation of the plasmon ...modes that such structures support, a field known as plasmonics. The increasing interest in plasmonics derives in large measure from the interplay between better fabrication techniques and an awareness of the potential that controlled plasmon modes have to offer. The combination of nanometer‐scale fabrication techniques and increasingly sophisticated numerical modeling capabilities thus enables a significant advance in our understanding of the science underlying plasmonics. Here, we survey some of the different structures that have been explored. We hope that this Review will spur others to continue the exploration of this fascinating topic.
The increasing interest in plasmonics derives in large measure from the interplay between better fabrication techniques and an awareness of the potential that controlled plasmon modes have to offer. The combination of nanometer‐scale fabrication techniques and increasingly sophisticated numerical modeling capabilities thus enables a significant advance in our understanding of the science underlying plasmonics. In this Review, some of the different structures that have been explored are surveyed.
We show that dye-doped polymers open an interesting route to controlling light at the nanoscale. Just as for the much better known metal-based plasmonic systems, propagating and localized modes are ...possible. We show that the attractive features offered by plasmonics, specifically enhanced optical fields and subwavelength field confinement, are also available with these materials. They thus open a new opportunity in nanophotonics in which fabrication and functionality might be achieved by harnessing molecular and supramolecular chemistry.
Biomarkers are now used in many areas of medicine but are still lacking for psychiatric conditions such as schizophrenia (SCZ). We have used a multiplex molecular profiling approach to measure serum ...concentrations of 181 proteins and small molecules in 250 first and recent onset SCZ, 35 major depressive disorder (MDD), 32 euthymic bipolar disorder (BPD), 45 Asperger syndrome and 280 control subjects. Preliminary analysis resulted in identification of a signature comprised of 34 analytes in a cohort of closely matched SCZ (n=71) and control (n=59) subjects. Partial least squares discriminant analysis using this signature gave a separation of 60-75% of SCZ subjects from controls across five independent cohorts. The same analysis also gave a separation of ~50% of MDD patients and 10-20% of BPD and Asperger syndrome subjects from controls. These results demonstrate for the first time that a biological signature for SCZ can be identified in blood serum. This study lays the groundwork for development of a diagnostic test that can be used as an aid for distinguishing SCZ subjects from healthy controls and from those affected by related psychiatric illnesses with overlapping symptoms.
We investigate the generation of THz pulses when arrays of silver nanoparticles are irradiated by femtosecond laser pulses, providing the first reproducible experimental evidence in support of recent ...theoretical predictions of such an effect. We assess our results in the context of a model where photoelectrons are produced by plasmon-mediated multiphoton excitation, and THz radiation is generated via the acceleration of the ejected electrons by ponderomotive forces arising from the inhomogeneous plasmon field. By exploring the dependence of the THz emission on the femtosecond pulse intensity and as a function of metal nanoparticle morphology, and by comparing measurements to numerical modeling, we are able to verify the role of the particle plasmon mode in this process.
We present results of the transmitted, reflected, and absorbed power associated with the enhanced transmittance of light through a silver film pierced by a periodic array of subwavelength holes. ...Comparing experimentally acquired dispersion curves under different polarization conditions shows that the transmission features of the array are consistent with p-polarized resonant modes of the structure. By exploring the regime in which no propagating diffracted orders are allowed, we further show that the transmittance maxima are associated with both reflectance minima and absorption maxima. These new results provide strong experimental evidence for transmission based on diffraction, assisted by the enhanced fields associated with surface plasmon polaritons.
A new research field is emerging in which ensembles of molecules are collectively hybridised with light in a process known as strong coupling. This hybridisation leads to the formation of new states ...that are part light and part matter, states known as polaritons. Here we offer an entry point into the field of molecular strong coupling. We include an overview of the essential phenomena and an introduction to the conceptual framework - considerable use is made of simple classical physics models since they are helpful in developing an intuitive understanding. Open questions are identified and discussed, as well as some of the exciting experimental and theoretical challenges that lie ahead.
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