Hyperbolic Metamaterials via Hierarchical Block Copolymer Nanostructures

TL;DR

This paper presents a novel method to create hyperbolic metamaterials with in-plane optical axes using hierarchical block copolymer nanostructures, enabling broad-spectrum hyperbolic behavior and enhanced fluorescence effects.

Contribution

It introduces a new fabrication approach for in-plane oriented hyperbolic metamaterials based on block copolymer dewetting and hierarchical nanostructures.

Findings

Achieved hyperbolic behavior in visible spectrum range.

Demonstrated high Purcell factor of 32 at 580 nm.

Enabled fluorescence lifetime reduction in nanodiamonds.

Abstract

Hyperbolic metamaterials (HMMs) offer unconventional properties in the field of optics, enabling opportunities for confinement and propagation of light at the nanoscale. In-plane orientation of the optical axis, in the direction coinciding with the anisotropy of the HMMs, is desirable for a variety of novel applications in nanophotonics and imaging. Here, a method for creating localized HMMs with in-plane optical axis, based on block copolymer (BCP) blend instability, is introduced. The dewetting of BCP thin film over topographically defined substrates generates droplets composed of highly ordered lamellar nanostructures in hierarchical configuration. The hierarchical nanostructures represent a valuable platform for the subsequent pattern transfer into a Au/air HMM, exhibiting hyperbolic behavior in a broad wavelength range in the visible spectrum. A computed Purcell factor as high as 32 at 580 nm supports the strong reduction in the fluorescence lifetime of defects in nanodiamonds placed on top of the HMM.