In this work we study the electromagnetic scattering by a magnetized cold plasma body, using a surface integral equation (SIE) formulation. To solve the problem, we express the fields inside the anisotropic region using appropriate discrete eigenvalue expansions and, applying the boundary conditions on body's surface, we obtain infinite sets of inhomogeneous algebraic equations from which, upon truncation, the expansion coefficients of the internal field are computed. Then, the expansion coefficients of the scattered field can be evaluated, as well as the bistatic scattering cross section. To conclude on the method's validity, we compute the cross sections, for different values of parameters, for prolate spheroidal bodies, and compare with the results obtained by the HFSS commercial software.

The development of nanostructured semiconductors with tailored morphology and electronic properties for surface-enhanced Raman scattering (SERS) has been attracting significant attention as a promising alternative to conventional coinage metal SERS substrates. In this work, functionalized TiO2 photonic crystals by graphene oxide nanocolloids (nanoGO) are demonstrated as highly sensitive, recyclable, plasmon-free SERS substrates that combine slow-photon amplification effects with the high adsorption capacity and surface reactivity of GO nanosheets. Comparative evaluation of photonic band gap engineered nanoGO–TiO2 inverse opal films was performed on methylene blue SERS detection under different laser excitations in combination with rigorous theoretical simulations of the photonic band structure. A very low detection limit of 6 × 10−7 M and an enhancement factor of 5 × 104 along with excellent self-cleaning performance and reusability could be achieved by the interplay of slow-photon effects assisted by interfacial charge transfer between the analyte and the nanoGO–TiO2 semiconducting substrate. Slow-photon management in combination with judicious engineering of chemical enhancement in photonic nanostructures is accordingly proposed as an advanced approach for the design of efficient dielectric SERS substrates.

Optomagnonic cavities have recently been emerging as promising candidates for implementing coherent photon-magnon interactions, for applications in quantum memories and devices, and next generation quantum networks. A key challenge in the design of such cavities is the attainment of high magnon-mediated optical-to-optical conversion efficiencies, which could, e.g., be exploited for efficient optical interfacing of superconducting qubits, as well as the practicality of the final designs, which ideally should be planar and amenable to on-chip integration. Here, on the basis of a novel time-Floquet scattering-matrix approach, we report on the design and optimization of a planar, multilayer optomagnonic cavity, incorporating a cerium-substituted yttrium iron garnet thin film, magnetized in-plane, and operating in the triple-resonant inelastic light scattering regime. This architecture allows for magnon-mediated optical-to-optical conversion efficiencies of about 5% under realistic conditions, which is orders of magnitude higher than that attained in alternative optomagnonic designs. Our results suggest a viable way forward for realizing practical information inter-conversion, with high efficiencies, between microwaves, strongly coupled to magnons, and optical photons, as well as a platform for fundamental studies of classical and quantum dynamics in magnetic solids and for the implementation of futuristic quantum devices.

A fully dynamic theoretical approach to layered optomagnonic structures, based on a time Floquet scattering-matrix method, is developed. Its applicability is demonstrated on a simple design of a dual photonic-magnonic cavity, formed by sandwiching a magnetic garnet thin film between two dielectric Bragg mirrors, subject to continuous excitation of a perpendicular standing spin wave. Some remarkable phenomena, including nonlinear photon-magnon interaction effects and enhanced inelastic light scattering in the strong-coupling regime, fulfilling a triple-resonance condition, are analyzed and the limitations of the quasistatic adiabatic approximation are established.

We report on judiciously designed stratified periodic structures of magnetic dielectric materials with a localized defect layer, which are able to concurrently confine light and spin waves in the same ultra-small defect region for a long time period, thus resulting in enhanced photon–magnon interaction and large dynamic optical frequency shift. Our results for a specific realization of such a one-dimensional, so-called photomagnonic, crystal magnetized at saturation perpendicular to the interfaces, obtained by means of rigorous calculations using scattering-matrix techniques, show that the inherently weak coupling between visible/near-infrared light and GHz-frequency spin waves can be greatly increased leading to strong modulation of the optical field through multi-magnon exchange mechanisms. Such novel multifunctional composite materials offer a promising platform for tailoring light–spin-wave coupling in view of fast and energy-efficient spin-optical information processing applications.