Directional Emission of Fluorescent Dye-Doped Dielectric Nanogratings for Lighting Applications

Abstract

By structuring a luminescent dielectric interface as a relief diffraction grating with nanoscale features, it is possible to control the intensity and direction of the emitted light. The composite structure of the grating is based on a fluorescent dye (Lumogen F RED 305) dispersed in a polymeric matrix (poly(methyl methacrylate)). Measurements demonstrate a significant enhancement of the emitted light for specific directions and wavelengths when the grating interface is compared to nonstructured thin films made of the same material. In particular, the maximum enhancement of photoluminescence for a given pump wavelength is obtained at an angle of incidence that is close to the Rayleigh anomaly condition for the first-order diffracted waves. In this condition, the maximum extinction of incident light is observed. Upon excitation with coherent and monochromatic sources, photoluminescence plots show that the Rayleigh anomalies confine the angular interval of the emitted light. Being the anomalies directly related to the pitch of the diffraction grating, the system can be thus implemented as an optical device whose directional emission can be designed for specific applications. The exploitation of nanoimprinting techniques for the fabrication of the luminescent grating enables production of the device on large areas, paving the way for low-cost lighting and solar applications.

Leveraging on ENZ Metamaterials to Achieve 2D and 3D Hyper‐Resolution in Two‐Photon Direct Laser Writing

“…Pushing the resolution to nanometric scale requires different approaches such as nanoimprinting, electron beam lithography, deep ultraviolet lithography albeit at the expense of reduced work area and time‐consuming procedure. [ 1,2 ] In the last decades, the new frontier of nanometric fabrication is embodied by two‐photon direct laser writing (TP‐DLW) lithography. By exploiting a nonlinear two‐photon absorption process, the involved photoresin is cured only in the focal point of the used laser, the voxel (short for volume pixel), thus sensibly increasing the resolution of realized nanostructures.…”

All‐Dielectric Toroidal Metasurfaces for Angular‐Dependent Resonant Polarization Beam Splitting

“…The experimental demonstration of such a compact, all-dielectric metasurface expands the research portfolio of resonant metasurfaces toward not only the investigation of the intriguing physics of toroidal modes but also to the engineering of functional millimeterwave components for polarization control, for instance, in the context of 5G wireless communication networks. which lensing, [5] reflection control and wavefront shaping, [6][7][8] manipulation of light emission or photoluminescence, [9][10][11] polarimetry, [12] highly-selective filtering, [13,14] or enhancement of nonlinear processes. [15,16] In this regard, it is common to study their resonant properties in terms of electric and magnetic multipoles, which are derived from the Taylor expansion of their EM fields and potentials, in order to gain physical insight into the possibility for intense light-matter interaction.…”

Color Gamut Behavior in Epsilon Near‐Zero Nanocavities during Propagation of Gap Surface Plasmons

“…The interaction of light with matter at the nanoscale is on the basis of a plethora of plasmonic and photonic effects that characterize several applied fields of nanoscience like enhanced Raman spectroscopy, biosensing, and metamaterials. [ 1–9 ] The case of light propagating into nanoguided systems is generally exploited for the fabrication of subwavelength optics and nanooptical devices, [ 10–13 ] exploiting also very interesting features as negative refractive index. [ 14,15 ] Several phenomena can take place, depending on the way the system is structured and excited.…”