All-dielectric Huygens’ meta-waveguides for resonant integrated photonics

The growing maturity of nanofabrication technology has recently enabled the deployment of high-quality subwavelength nanostructures on photonic chips. A combination of existing photonic waveguide technology with nanophotonics and paradigms adapted from the field of optical metamaterials opens new avenues towards photonic integrated circuits providing unprecedented control of guided light waves. However, developing new functionalities while preserving both compatibility with current technology and the efficiencies required by existing and emerging applications remains a major challenge in on-chip nanophotonics. Here, we propose and demonstrate a radically new type of silicon nanophotonic waveguide consisting of a chain of resonantly forward scattering nanoparticles empowered by spectrally overlapping electric and magnetic dipolar Mie-type resonances. The propagation loss of the realized meta-waveguides in the telecom spectral range is as low as 0.4 dB/mm, exceeding the current record for Mie-resonant waveguides by more than an order of magnitude. Furthermore, the meta-waveguides support a negative group index over a broad spectral range of 60 nm and several millimeters of propagation distance, as well as regions of vanishing and anomalous dispersion within the transmission band. Finally, we show that meta-waveguide architectures composed of resonantly forward scattering nanoparticles can implement sharp bends with bending radii below 3 µm, and efficiently split the input signal within just 315 nm propagation length. Our work does not only contribute to addressing the challenges of miniaturization, dispersion and scattering control in on-chip photonics, but furthermore opens up completely new opportunities for enhanced light-matter interactions, interfacing with nanophotonic components, as well as nonlinear, ultrafast and quantum optics in resonant integrated light-guiding architectures.