Hyperbolic Metamaterials via Hierarchical Block Copolymer Nanostructures

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.

All-Polymer Microcavities for the Fluorescence Radiative Rate Modification of a Diketopyrrolopyrrole Derivative

“…Both radiative rate enhancement and radiative rate suppression have been well-demonstrated in metallic and inorganic structures. Indeed, the latter have been dominating the photonics playground thanks to their low losses and optimal radiation confinement .…”

Solvent-assisted self-assembly of block copolymer thin films

“…6,[11][12][13][14][15][16] Arguably, the greatest advantage of BCP-mediated manufacturing of nanoscale patterns is the low-cost and high-throughput of this approach compared to the conventional methods such as photo-and e-beam lithography. Numerous applications for BCP-ordered templates have been proposed, including optical coatings, 17,18 metamaterials, [19][20][21] photonic crystals, 22,23 plasmonic nanostructures, 24,25 and membranes. 26,27 These emerging applications have propelled research efforts aimed at understanding and harnessing the self-assembly of BCP thin films and led to the development of various directed selfassembly (DSA †) methods.…”

Control of near-infrared dye fluorescence lifetime in all-polymer microcavities

“…24–29 Even though careful molecular design, 30 supramolecular assemblies 31–33 and dye blends 34,35 provide an approach to fluorescence kinetics control, using photonic structures offers an additional tool having broad applicability, high effectiveness and straight-forward experimental method. 19,36,37 This offers more flexibility in achieving fluorescence control in solid state devices through simply incorporating the microcavities without changing the dye system, in particular when polymer and flexible materials are used.…”