We report the design of highly efficient optical antennas employing a judicious synthesis of metallic and dielectric materials. In the proposed scheme, a pair of metallic coupled nanoparticles ...permits large enhancements in both excitation strength and radiative decay rates, while a high refractive index dielectric microsphere is employed to efficiently collect light without spoiling the emitter quantum efficiency. Our simulations indicate potential fluorescence rate enhancements of 3 orders of magnitude over the entire optical frequency range.
A photon interacts efficiently with an atom when its frequency corresponds exactly to the energy between two eigenstates. But at the nanoscale, homogeneous and inhomogeneous broadenings strongly ...hinder the ability of solid-state systems to absorb, scatter or emit light. By compensating the impedance mismatch between visible wavelengths and nanometre-sized objects, optical antennas can enhance light-matter interactions over a broad frequency range. Here we use a DNA template to introduce a single dye molecule in gold particle dimers that act as antennas for light with spontaneous emission rates enhanced by up to two orders of magnitude and single photon emission statistics. Quantitative agreement between measured rate enhancements and theoretical calculations indicate a nanometre control over the emitter-particle position while 10 billion copies of the target geometry are synthesized in parallel. Optical antennas can thus tune efficiently the photo-physical properties of nano-objects by precisely engineering their electromagnetic environment.
The spatial and spectral properties of three-dimensional photonic jets are studied in a framework employing rigorous Lorentz-Mie theory. The contributions to the field from each spectral component ...are studied quantitatively and highlight the distinctive features of photonic jets. In particular, the role of evanescent field in photonic jets generated by small spheres is investigated. Secondary lobes in the propagative frequency distribution are also singled out as a distinctive property of photonic jets. It is shown that these differences lead to angular openings of photonic jets at least twice as small as those in comparable 'Gaussian' beams.
Extensions of the Resonant State or (Quasi-normal mode) formalism are shown to permit unified descriptions of the true ’bound’ states within the framework of the ’leaky’ mode formulation of basis ...sets. We review recent progress in the famed ’normalization/regularization’ problems of the QNMs modes as well as the necessity of including ’background’ contributions whose expressions can be determined through response function sum-rules.
We demonstrate that symmetric or asymmetric gold nanoparticle dimers with substantial scattering cross sections and plasmon coupling can be produced with a perfectly controlled chemical environment ...and a high purity using a single DNA linker as short as 7 nm. A statistical analysis of the optical properties and morphology of single dimers is performed using darkfield and cryo-electron microscopies. These results, correlated to Mie theory calculations, indicate that the particle dimers are stretched in water by electrostatic interactions.
Given a number field K and a finite set S of places of K, the first main result of this paper shows that the quadratic rational maps ϕ : ℙ1 → ℙ1 defined over K which have good reduction at all places ...outside S form a Zariskidense subset of the moduli space 𝓜2 parametrizing all isomorphism classes of quadratic rational maps. We then consider quadratic rational maps with double unramified fixed-point structure, and our second main result establishes a Zariski nondensity result for the set of such maps with good reduction outside S. We also prove a variation of this result for quadratic rational maps with unramified 2-cycle structure.
Physical systems are characterized by their transfer operators in the harmonic domain. These operators are usually locally approximated as rational functions or pole expansions. We generalize this ...result and introduce the Multiple-Order Singularity Expansion Method (MOSEM) which offers an exact description of linear systems in terms of their singularities and Laurent series coefficients or zeros. The interest of this approach is first illustrated by the simple but fundamental case of a dispersive Fabry-Perot cavity, where it provides an analytical expression of the reflected field in both the time and harmonic domains. In a second step, we show that this method must be applied for defining the complex expression of the dielectric permittivity that describes the physical response of a system (the material) to an excitation field. This rigorous expression of the permittivity is shown to provide highly accurate results for a broad range of materials.
In this article, I argue that as technology advances at ever faster rates, it is imperative to approach each new technological development through the lens of core values. Criminal and community ...justice and higher education are discussed to highlight how technological developments can challenge our values and progress on parallel tracks. In community justice, technology has been most prominent in the utilization of electronic monitoring and tracking. EM was initially promoted as an alternative to custody but is increasingly utilized as an adjunct to custody, an extra element of punishment, or as an extra level of surveillance. It is important to interrogate the values of the use of this technology and the impact of monitoring on individuals and diverse and possibly disadvantaged groups. It is also important to study if the use of technology support inhibits rehabilitation. Higher Education has a long history of being challenged and disrupted by technology. Most recently, it is the use of Artificial Intelligence that has raised anxiety. If the skills and abilities that universities teach become redundant and how educators tell whether students are submitting assignments written by themselves are also important to research. The results of such discussions provide educational values in the purpose and nature of education.
Under exceptional circumstances, light and molecules bond together, creating new hybrid light–matter states with far-reaching consequences for these strongly coupled entities. The present article ...describes the quantum-mechanical foundation of strong-coupling and experimental evidence for molding the radiation properties of nanoprobes by strong-coupling. When applied to tracing and marking, the new fluorometry technique proposed here, which harnesses strong-coupling, has a triple advantage compared to its classical counterparts such as DNA tracing. It is fast, and its signal-to-noise ratio can be improved by spectral filtering; moreover, it reveals a specific quantum signature of the strong-coupling, which is extremely difficult to reproduce classically, thereby opening the door to new anti-counterfeiting strategies.
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