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Hyperbolic metamaterials can enhance spontaneous emission, but the radiation-matter coupling is not optimized if the light source is placed outside such media. We demonstrate a 3-fold improvement of the Purcell factor over its outer value and a significant enlargement in bandwidth by including the emitter within a Si/Ag periodic multilayer metamaterial. To extract the plasmonic modes of the structure into the far field we implement two types of 1D grating with triangular and rectangular profile, obtaining a 10-fold radiative enhancement at visible frequencies.

Modern miniaturization and the digitalization of characterization instruments greatly facilitate the diffusion of technological advances in new fields and generate innovative applications. The concept of a portable, inexpensive and semi-automated biosensing platform, or lab-on-a-chip, is a vision shared by many researchers and venture industries. Under this scope, we present a semiconductor monolithic integration approach to conduct surface plasmon resonance studies. This technology is already commonly used for biochemical characterization in pharmaceutical industries, but we have reduced the technological platform to a few nanometers in scale on a semiconductor chip. We evaluate the signal quality of this nanophotonic device using hyperspectral-imaging technology, and we compare its performance with that of a standard prism-based commercial system. Two standard biochemical agents are employed for this characterization study: bovine serum albumin and inactivated influenza A virus. 2 However, the delocalization of arbitrary biochemical analyses is still a challenge today, where nanotechnogy could present solutions for the development of micro total analysis systems (mTAS) potentially capable of portable biodiagnostics. 3 We present here the results of an effort towards such a solution through a wholly integrated semiconductor-based surface plasmon resonance (SPR) nanometric platform.SPR is a well-established optical phenomenon where an electromagnetic (EM) beam of a specific energy and incident wavevector (angle) can induce a resonant group oscillation within the surface electrons of a metal-dielectric interface. 4 The resulting EM field is evanescent in nature, with typical confinement of 200 nm for visible light. Therefore, the coupling conditions of this resonance effect are very much dictated by the surface conditions within the evanescent field and can consequently be employed for many dynamic biochemistry studies. 5 The SPR biocharacterization platform presents many advantages over most other methods; its range of application is very broad, especially for unspecific binding studies, 5 the method can offer very high sensitivities to subtle surface refractive index changes 6 and even enable

The surface plasmon resonance tracking over metal surfaces is a well-established, commercially available, biochemical quantification tool primarily applied in research. The utilization of such a tool is, however, constrained to highly specialized industries, capable of justifying the human and instrumental resource investments required by the characterization method. We have proposed to expand the field of application of this biosensing approach by redesigning this method through the integration and miniaturization within a semiconductor platform. Uncollimated and broadband emission from a light-emitting semiconductor is employed to couple a continuum of surface plasmon modes over a metal-dielectric architecture interfaced with a GaAs-AlGaAs substrate. A tensor version of rigorous coupled wave theory is employed to optimize the various fabrication specifications and to predict the light scatterings over a wide range of variables. We then present a hyperspectral characterization microscope capable of directly mapping the dispersion relation of scattered light, including diffracted surface plasmons, as an intensity distribution versus photon energy and surface wavevectors. Measurements carried out in a buffered solution demonstrate the accurate description of the uncollimated and broadband surface plasmon states. Finally, we introduce a simplified method of dispersion mapping, in which quasi-conic cross-sections of the light's scattering can be acquired directly, thus monitoring surficial responses in as fast as 1.2 s. This is over 300 times faster than required by implementing full dispersion mapping. While compromising on the volume of collected information, this method, combined with the solid-state integration of the platform, shows great promise for the fast detection of biochemical agents. Keywords: biosensors; light scattering; optical devices; semiconductors; surface plasmon resonance INTRODUCTION Surface plasmon resonance (SPR) is a well-established and easy-toinduce phenomenon enabling the study of surficial optical properties, such as those related to the alterations of the local dielectric constants. The resonance tracking of the surface plasmon (SP) coupling has already found a wide range of applications, especially in the field of biochemical analysis, where SPR systems are employed to determine the concentration of molecules and kinetics of intermolecular interactions.1 Using proper stabilization and correction procedures, it has been demonstrated that the SPR technique can be used to detect biochemical fluctuations inducing refractive index changes lower than 10 28 refractive index unit. 2 The same approach can also be employed for the spatial imaging of binding events.3 However, the SPR technology has remained in the realm of trained professionals, in academic laboratories and within specialized industries, requiring relatively large space, capital investment and the support of qualified personnel.

Abstract:The optical properties of thin gold films with thickness varying from 2.5 nm to 30 nm are investigated. Due to the quantum size effect, the optical constants of the thin gold film deviate from the Drude model for bulk material as film thickness decreases, especially around 2.5 nm, where the electron energy level becomes discrete. A theory based on the self-consistent solution of the Schrödinger equation and the Poisson equation is proposed and its predictions agree well with experimental results.