We calculate the radiative heat transfer between two identical metallic one-dimensional lamellar gratings. To this aim we present and exploit a modification to the widely used Fourier modal method, known as adaptive spatial resolution, based on a stretch of the coordinate associated with the periodicity of the grating. We first show that this technique dramatically improves the rate of convergence when calculating the heat flux, allowing us to explore smaller separations. We then present a study of heat flux as a function of the grating height, highlighting a remarkable amplification of the exchanged energy, ascribed to the appearance of spoof-plasmon modes, whose behavior is also spectrally investigated. Differently from previous works, our method allows us to explore a range of grating heights extending over several orders of magnitude. By comparing our results to recent studies we find a consistent quantitative disagreement with some previously obtained results going up to 50%. In some cases, this disagreement is explained in terms of an incorrect connection between the reflection operators of the two gratings.

The recent developments of nitride nanophotonics, based on photonic crystal membrane nanocavities and microdisk resonators, pave the way to a novel nanophotonic platform. Here we present two recent achievements: first we demonstrate the room-temperature operation of a nitride microlaser emitting in the deep UV spectral range (=275 nm) with GaN/AlN multiple quantum wells. Secondly we tailor the second-harmonic generation of a cw near infra-red radiation coupled to a high quality factor photonic crystal cavity.

The spatial dynamics of the formation of a polariton condensate under a tightly focused excitation is imaged through 2D near-field and far-field 2D tomography in a ZnO microcavity, up to room temperature. The modelling exhibits the role of the outwards polariton flux caused by the reservoir repulsion, that leads to a 3 to 10 fold increase of the condensation threshold and is imprinted in the shape of the polariton condensate

We propose a model taking into account the periodic spatial modulation of a doped gra- phene sheet conductivity when it is placed in the vicinity of a dielectric grating. We then compute the absorption and study the excitation of surface plasmons on such a structure. We show that it is possible to excite surface modes leading to very high absorption. Our findings could be of interest in the design of graphene-based plasmonic devices and sensors working in the infra-red and the terahertz regions of the electromagnetic spectrum.

We propose a model taking into account the periodic spatial modulation of a doped graphene sheet conductivity influenced by a dielectric grating. We obtain the dispersion relation through the Fourier Modal Method (FMM) and study the excitation of surface plasmons on such structures. We compute and study the spatially localized fields on the graphene sheet.

We derive the explicit expression for the Casimir energy between a sphere and a 1D grating under thermal equilibrium, in terms of the sphere and grating reflection matrices, and valid for arbitrary materials, sphere radius, and grating geometric parameters.

Behind the appellation “modal methods”, for diffraction gratings, one can find a variety of methods sharing in common the development of the fields in terms of basis functions that can be either Fourier exponentials hence the name Fourier Modal Method (FMM), or polynomials leading to the family of Polynomial Modal Methods (Legendre, Tchebychev, and Gegenbauer). These approaches may not behave in the same way when dealing with gratings with extreme features such as a very low or very high filling ratios. In the present work, we address such a problem and compare the performances of the different Modal Methods.