Extremely Polarized and Efficient Hot Electron Intraband Luminescence from Aluminum Nanostructures for Nonlinear Optical Encoding

Abstract

Hot electron intraband luminescence from plasmonic nanostructures is of critical importance for integrated photonic devices and applications in ultracompact nanospectrometer, bioimaging, information encryption et al. Although, the past few decades have witnessed tremendous progress in enhancing the luminescence efficiency of plasmonic nanostructures, the luminescence is usually unpolarized or partially polarized and difficult to be tailored because of its incoherent and broadband feature, significantly limiting its applications. Here the current limitation, demonstrating extremely polarized hot electron intraband luminescence with record‐high degree of linear polarization (≈1) and ≈40 000‐fold enhancement from judiciously designed aluminium (Al) plasmonic nanostructures, is broken through. The designed nanostructures exhibit strong polarization‐dependent anisotropic scattering across the visible band which efficiently modulates the luminescence in orthogonal directions. Leveraging this appealing feature, high‐contrast analyzer controlled optical image encryption and camouflage for information security applications are demonstrated. This research lays the groundwork for integrated nonlinear photonic devices based on complementary metal–oxide–semiconductor (CMOS)‐compatible plasmonic materials and paves the way for ultracompact on‐chip photonic devices demanding polarized white light sources.

Broadband and Highly Directional Visible Light Scattering by Laser-Splashed Lossless TiO2 Nanoparticles

“…As the building block of metamaterials and metasurfaces, nanoparticles play a crucial role in controlling light propagation and regulating the light field distribution [1,2]. Although metal nanoparticles supporting localized surface plasmons have been widely investigated and are found in many applications such as Raman scattering enhancement [3], biosensing [4], metasurfaces [5], nonlinear plasmonics [6,7] and photovoltaics [8][9][10], their large optical losses and lack of magnetic resonances have hindered their further development. All-dielectric nanomaterials have recently emerged as a promising alternative to plasmonic nanoparticles in constituting high-efficiency photonic devices due to the coexistence of electric and magnetic resonances and lower optical losses as well.…”

Photonics Empowered Passive Radiative Cooling

“…Metasurfaces [ 37,76–82 ] show unparalleled capabilities on controlling light–mater interaction at the subwavelength scale by a simple array of meta‐atoms, greatly easing the fabrication complexity compared with their counterpart metamaterials. Structures, such as plasmonic perfect absorbers [ 83–91 ] and all‐dielectric absorbers, [ 92 ] can be optimized for achieving selective emitters by machine learning methods. In typical metal–insulator–metal plasmonic absorber structures, complete absorption occurs at specific wavelength.…”

Reversible Thermochromic Perovskite-Based Dynamic Optical Encryption and Holographic Inference

“…In the past decade, perovskites have emerged as a species of prospective materials to construct high-performance optoelectronic devices such as solar cells, photodetectors, and light-emitting diodes due to their long carrier lifetime, high carrier mobility, and solution processability. − Based on their superior properties of a high refractive index (approximately within the interval of 2.2–2.55) and a flexible optical band gap, perovskites have recently started to cut a striking figure in information photonic devices, for instance, microlasers, , nonlinear emission, optical data storage, metasurfaces, etc. Due to the abundant categories of chemical constituents and lattice structures, perovskite species can provide a diversified and selectable material platform to achieve dynamic photonic devices.…”