Recent advances in metamaterial integrated photonics
Journal Articles
Overview
Research
Identity
Additional Document Info
View All
Overview
abstract
Since the invention of the silicon subwavelength grating waveguide in
2006, subwavelength metamaterial engineering has become an essential
design tool in silicon photonics. Employing well-established
nanometer-scale semiconductor manufacturing techniques to create
metamaterials in optical waveguides has allowed unprecedented control
of the flow of light in photonic chips. This is achieved through
fine-tuning of fundamental optical properties such as modal
confinement, effective index, dispersion, and anisotropy, directly by
lithographic imprinting of a specific subwavelength grating structure
onto a nanophotonic waveguide. In parallel, low-loss mode propagation
is readily obtained over a broad spectral range since the
subwavelength periodicity effectively avoids losses due to spurious
resonances and bandgap effects. In this review we present recent
advances achieved in the surging field of metamaterial integrated
photonics. After briefly introducing the fundamental concepts
governing the propagation of light in periodic waveguides via
Floquet–Bloch modes, we review progress in the main application areas
of subwavelength nanostructures in silicon photonics, presenting the
most representative devices. We specifically focus on off-chip
coupling interfaces, polarization management and anisotropy
engineering, spectral filtering and wavelength multiplexing,
evanescent field biochemical sensing, mid-infrared photonics, and
nonlinear waveguide optics and optomechanics. We also introduce a
nascent research area of resonant integrated photonics leveraging Mie
resonances in dielectrics for on-chip guiding of optical waves, with
the first Huygens’ metawaveguide recently demonstrated. Finally, we
provide a brief overview of inverse design approaches and
machine-learning algorithms for on-chip optical metamaterials. In our
conclusions, we summarize the key developments while highlighting the
challenges and future prospects.
