Full-color enhanced second harmonic generation using rainbow trapping in ultrathin hyperbolic metamaterials

Abstract

Metasurfaces have provided a promising approach to enhance the nonlinearity at subwavelength scale, but usually suffer from a narrow bandwidth as imposed by sharp resonant features. Here, we counterintuitively report a broadband, enhanced second-harmonic generation, in nanopatterned hyperbolic metamaterials. The nanopatterning allows the direct access of the mode with large momentum, rendering the rainbow light trapping, i.e. slow light in a broad frequency, and thus enhancing the local field intensity for boosted nonlinear light-matter interactions. For a proof-of-concept demonstration, we fabricated a nanostructured Au/ZnO multilayer, and enhanced second harmonic generation can be observed within the visible wavelength range (400-650 nm). The enhancement factor is over 50 within the wavelength range of 470-650 nm, and a maximum conversion efficiency of 1.13×10−6 is obtained with a pump power of only 8.80 mW. Our results herein offer an effective and robust approach towards the broadband metasurface-based nonlinear devices for various important technologies.

THz Radiation Efficiency Enhancement from Metal–ITO Nonlinear Metasurfaces

“…The absorption ( A ) of the samples is calculated according to A = 1 – T – R . An increase in the absorption suggests higher Ohmic losses and increased localized fields, which can potentially lead to a stronger nonlinear response as previous studies have reported. − …”

Effective excitation of bulk plasmon-polaritons in hyperbolic metamaterials for high-sensitivity refractive index sensing

“…1. Recent years, HMMs have been demonstrated the ability in ultrabroadband and anisotropic absorption, 23,24 negative refraction, 25,26 enhancing second harmonic generation, 27 and many advanced applications. [28][29][30] NHMM exhibits anisotropic optical properties, which can be approximately described using the effective medium theory (EMT).…”

A planar plasmonic nano-gap and its array for enhancing light-matter interactions at the nanoscale

“…In the past few decades, great efforts have been made to investigate GSP in different types of metallic structures, including flat metal films separated by a dielectric layer, [2][3][4] coupled metal nanoparticles, 5 metal nanoparticles on flat metal film structures (MNOF), [6][7][8] and their derivatives. 9,10 Various novel plasmonic phenomena, such as nonlocality, 11,12 huge electromagnetic enhancements, 13 ultra-strong coupling, 14,15 quantum tunneling, 16,17 and charge-transfer plasmons, 18 have been revealed, leading to a few interesting applications like surface-enhanced Raman scattering (SERS) with sensitivity down to the single-molecule level, 19,20 photothermal cancer therapy, [21][22][23] super-continuum generation, 24,25 and plasmon-enhanced electron emission. [26][27][28][29][30] In comparison with GSP modes from free-standing coupled metallic nanoparticles or MNOF, planar coupled nanostructures supported on a flat substrate are more favorable for device applications for the following reasons: (i) planar architectures can be facilely integrated with other functional components; (ii) the gap formed by planar structures is more easily accessed.…”

“…In the past few decades, great efforts have been made to investigate GSP in different types of metallic structures, including flat metal films separated by a dielectric layer, 2–4 coupled metal nanoparticles, 5 metal nanoparticles on flat metal film structures (MNOF), 6–8 and their derivatives. 9,10 Various novel plasmonic phenomena, such as non-locality, 11,12 huge electromagnetic enhancements, 13 ultra-strong coupling, 14,15 quantum tunneling, 16,17 and charge-transfer plasmons, 18 have been revealed, leading to a few interesting applications like surface-enhanced Raman scattering (SERS) with sensitivity down to the single-molecule level, 19,20 photothermal cancer therapy, 21–23 super-continuum generation, 24,25 and plasmon-enhanced electron emission. 26–30…”