2020/05/31 by Sisira Suresh, Orad Reshef, M. Zahirul Alam +3 · 86 citations
Engineering · Materials Science · Physics and Astronomy · #Condensed matter physics #Materials science #Metamaterial #Metamaterials and Metasurfaces Applications #Nonlinear optical #Nonlinear optics #Nonlinear system #Optics #Optoelectronics #Physics #Plasmonic and Surface Plasmon Research #Quantum Mechanics and Non-Hermitian Physics #Quantum mechanics #Zero (linguistics) #physics.optics
paper · pdf · doi:10.1021/acsphotonics.0c01178
published in ACS Photonics 8(1), 125-129 (American Chemical Society) · 24 pages, includes supporting information
openalex publication_date 2020/12/11 · arxiv created 2021/02/24 · arxiv updated 2021/02/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Optical materials with vanishing dielectric permittivity, known as epsilon-near-zero (ENZ) materials, have been shown to possess enhanced nonlinear optical responses in their ENZ region. These strong nonlinear optical properties have been firmly established in homogeneous materials; however, it is as of yet unclear whether metamaterials with effective optical parameters can exhibit a similar enhancement. Here, we probe an optical ENZ metamaterial composed of a subwavelength periodic stack of alternating Ag and SiO 2 layers and measure a nonlinear refractive index n 2 = (1.2 ± 0.1) × 10 –12 m 2 /W and nonlinear absorption coefficient β = (−1.5 ± 0.2) × 10 –5 m/W at its effective zero-permittivity wavelength. The measured n 2 is 10 7 times larger than n 2 of fused silica and 4 times larger than the n 2 of silver. We observe that the nonlinear enhancement in n 2 scales as 1/( n 0 Re[ n 0 ]), where n 0 is the linear effective refractive index. As opposed to homogeneous ENZ materials, whose optical properties are dictated by their intrinsic material properties and hence are not widely tunable, the zero-permittivity wavelength of the demonstrated metamaterials may be chosen to lie anywhere within the visible spectrum by selecting the right thicknesses of the subwavelength layers. Consequently, our results offer the promise of a means to design metamaterials with large nonlinearities for applications in nanophotonics at any specified optical wavelength.