Ultra-compact, densely integrated optical components manufactured on a CMOS-foundry platform are highly desirable for optical information processing and electronic-photonic co-integration. However, the large spatial extent of evanescent waves arising from nanoscale confinement, ubiquitous in silicon photonic devices, causes significant cross-talk and scattering loss. Here, we demonstrate that anisotropic all-dielectric metamaterials open a new degree of freedom in total internal reflection to shorten the decay length of evanescent waves. We experimentally show the reduction of cross-talk by greater than 30 times and the bending loss by greater than 3 times in densely integrated, ultra-compact photonic circuit blocks. Our prototype all-dielectric metamaterial-waveguide achieves a low propagation loss of approximately 3.7±1.0 dB/cm, comparable to those of silicon strip waveguides. Our approach marks a departure from interference-based confinement as in photonic crystals or slot waveguides, which utilize nanoscale field enhancement. Its ability to suppress evanescent waves without substantially increasing the propagation loss shall pave the way for all-dielectric metamaterial-based dense integration.
Saman Jahani, Sangsik Kim, Jonathan Atkinson, Justin C. Wirth, Farid Kalhor, Abdullah Al Noman, Ward D. Newman, Prashant Shekhar, Kyunghun Han, Vien Van, Raymond G. DeCorby, Lukas Chrostowski, Minghao Qi & Zubin Jacob, "Controlling evanescent waves using silicon photonic all-dielectric metamaterials for dense integration," Nat Commun 9, 1893 (2018)
Our work led to a fundamental understanding of universal spin-momentum locking of light and near-field properties of light's polarization.
We introduced a universal right handed electromagnetic triplet consisting of electromagnetic momentum, decay and spin.
We have predicted the existence of a new topological phase of matter exhibiting photon spin-1 quantization.