Large Optical Modulation of Dielectric Huygens' Metasurface Absorber
Journal
Advanced Optical Materials
Journal Volume
11
Journal Issue
10
Start Page
2300102
ISSN
2195-1071
2195-1071
Date Issued
2023-04-03
Author(s)
Abstract
High-index nanostructures are found to exhibit large nonlinearity of spectral responses under photoexcitation, which is applicable to all-optical modulation. The nonlinearity stems from Mie-type resonance shift due to photoinduced variation of refractive index. Here, amorphous silicon-based Huygens’ metasurface absorber and ultrafast excitation are used to demonstrate two orders of magnitude enhancement of modulation depth, both theoretically and experimentally, when electric dipole lattice resonance matches the magnetic dipole resonance. Within a few square micrometer spatial confinement and picosecond scale delay, over 100% photothermal modulation depth is experimentally achieved at matched resonance condition. This concept is not limited to photothermal modulation in the amorphous silicon but is applicable to dielectric materials with various mechanisms to achieve modulation of refractive index. This work opens the avenue toward all-optical information processing via optimized modulation by careful spatiotemporal and spectral control over a metasurface.
Subjects
Kerker effects
Mie resonances
photothermal effects
silicon nanostructures
SDGs
Publisher
Wiley
Type
journal article