Plasmonic quasicrystals for designable ultra broadband transmission enhancement and second harmonic generation

TL;DR

This paper demonstrates the design and fabrication of plasmonic quasicrystals that achieve broadband, polarization-independent transmission enhancement and second harmonic generation, advancing applications in energy harvesting and nonlinear optics.

Contribution

It introduces a novel approach to creating plasmonic quasicrystals with customizable symmetry and broadband optical properties, unlike traditional periodic plasmonic structures.

Findings

Broadband, polarization-independent transmission enhancement observed.

Successful fabrication of large-area quasicrystal patterns in metal films.

Enhanced second harmonic generation across a broad spectrum.

Abstract

Quasi-crystals are intriguing as they exhibit rotational symmetry and long range ordering but lack translational symmetry. 2-dimensional metal-dielectric patterns are interesting to make use of surface plasmon polariton (SPP) mediated local field enhancement and for near dispersionless SPP modes. In plasmonic crystals, the orientation and periodicity of the pattern dictate the polarization response and the discrete plasmon resonances while the interfaces define the plasmon dispersion. However, unique properties of plasmonic quasicrystals lead to polarization independence, designable k-space and broadband transmission enhancement due to SPP mediation. These are useful in many applications like energy harvesting, nonlinear optics and quantum plasmonics. We demonstrate design and fabrication of large area quasicrystal air hole patterns of pi/5 symmetry in metal film in which broadband, launch angle and polarization independent transmission enhancement as well as broadband second harmonic generation are observed. Designable transmission response, other symmetries and tilings are possible.