Plasmonic Metastructures and Nanocomposites with a Narrow Transparency Window in a Broad Extinction Spectrum

TL;DR

This paper introduces plasmonic nanomaterials with a broad extinction spectrum that feature a narrow, tunable transparency window, enabling selective transmission within a wide range of wavelengths for optical applications.

Contribution

It presents a novel design of nanocomposite materials with a narrow transparency window within a broad extinction spectrum, based on nanorod ensembles and their plasmonic properties.

Findings

Narrow transparency window is achieved by mixing nanorods of different sizes.

The width of the transparency window depends on plasmon broadening effects.

Increasing nanocrystal concentration narrows the transparency window.

Abstract

We propose and describe plasmonic nanomaterials with unique optical properties. These nanostructured materials strongly attenuate light in a broad wavelength interval ranged from 400 nm to 5 um but exhibit a narrow transparency window centered at a given wavelength. The main elements are nanorods and nano-crosses of variable sizes. The nanomaterial can be designed as a solution, nanocomposite film, metastructure or aerosol. The principle of the formation of the transparency window in the abroad extinction spectrum is based on the narrow lines of longitudinal plasmons of single nanorods and nanorod complexes. To realize the spectrum with a transmission window, we design a nanocomposite material as a mixture of nanorods of different sizes. Simultaneously, we exclude nanorods of certain length from the nanorod ensemble. The width of the plasmonic transparency window is determined by the intrinsic and radiative broadenings of the nanocrystal plasmons. We also describe the effect of narrowing of the transparency window with increasing the concentration of nanocrystals. Two well-established technologies can be used to fabricate such nano- and metamaterials, the colloidal synthesis and lithography. Nanocomposites proposed here can be used as optical materials and coatings for shielding of electromagnetic radiation in a wide spectral interval with a simultaneous possibility of communication using a narrow transparency window.