Ultra-broadband Tunable Resonant Light Trapping in a Two-dimensional Randomly Microstructured Plasmonic-photonic Absorber

Abstract

Recently, techniques involving random patterns have made it possible to control the light trapping of microstructures over broad spectral and angular ranges, which provides a powerful approach for photon management in energy efficiency technologies. Here, we demonstrate a simple method to create a wideband near-unity light absorber by introducing a dense and random pattern of metal-capped monodispersed dielectric microspheres onto an opaque metal film; the absorber works due to the excitation of multiple optical and plasmonic resonant modes. To further expand the absorption bandwidth, two different-sized metal-capped dielectric microspheres were integrated into a densely packed monolayer on a metal back-reflector. This proposed ultra-broadband plasmonic-photonic super absorber demonstrates desirable optical trapping in dielectric region and slight dispersion over a large incident angle range. Without any effort to strictly control the spatial arrangement of the resonant elements, our absorber, which is based on a simple self-assembly process, has the critical merits of high reproducibility and scalability and represents a viable strategy for efficient energy technologies.

Omnidirectional, Broadband, and Polarization‐Independent Near‐Perfect Light Absorption from Surface Plasmonic Excitation of a Corrugated Au–SiO2–Au Structure Fabricated with a Self‐Assembled Silica Opal Template

“…We attribute this discrepancy to the apparent irregularities in the cMIM structure shown in Figure 1b, which presumably results from imperfections in the opal substrate compared with an ideal face‐centered‐cubic crystalline structure. A similar trend has also been observed in the study by Liu et al, [ 15 ] where the simulation and experiment showed that a Au film coated on a monolayer of randomly distributed polystyrene (PS) nanospheres (on a Au‐coated quartz substrate) produces higher absorption than that of the Au film coated on a periodic monolayer of PS nanospheres with the same size (also on Au‐coated quartz substrate).…”

“…Although a single layer of nanotextured metal film has been reported to be sufficient for achieving broadband NPA, [ 11–17 ] for device applications, structural designs that adapt metal–insulator–metal (MIM) sandwich schemes are more commonly employed because of the flexibility they offer for the optimization of targeted light‐material interactions. [ 7–9,18–23 ] In MIM structures for NPA, an optically opaque bottom metal layer is generally used to achieve vanishing transmission in the device.…”

Glassy Microspheres for Energy Applications

“…In all these cases, the synthesis process of organic or inorganic microspheres does not present significant difficulties and the width of size distribution of the produced particles is not a critical factor; current research is aimed at optimizing the choice of the mean size and the usage protocol for the specific application considered. There is, however, a research topic of growing interest where the size of the micrometric and sub-micrometric spheres must be controlled: it is the case of photonic crystal structures and arrays of resonators, whose properties may be exploited to improve light harvesting in solar cells [ 137 , 138 , 139 , 140 ]. A deeper study of the self-organization processes of colloidal particles and of the process parameters would be important to optimize the design and implementation of photonic crystal structures [ 137 , 139 ].…”

Densely Distributed Multiple Resonance Modes in a Fan-Shaped Plasmonic Nanostructure Demonstrated by FEM Simulations

“…Much attention has been devoted to SPP structures since they have many attractive capabilities, such as overcoming the optical diffraction limit, forming strongly localized fields on metal-dielectric surfaces, and manipulating light at nanoscale [6,7,8,9,10,11,12,13]. Due to these unique characteristics, a variety of SPP devices with special functions have been theoretically proposed and experimentally demonstrated, such as optical modulators, logic processors, power splitters, optical filters, and biochemical sensors [14,15,16,17,18,19,20,21]. Interestingly, SPP is regarded as one of the most promising technologies for realizing all-optical on-chip integrated systems.…”