All-dielectric scale invariant waveguide

Abstract

Total internal reflection (TIR) governs the guiding mechanisms of almost all dielectric waveguides and therefore constrains most of the light in the material with the highest refractive index. The few options available to access the properties of lower-index materials include designs that are either lossy, periodic, exhibit limited optical bandwidth or are restricted to subwavelength modal volumes. Here, we propose and demonstrate a guiding mechanism that leverages symmetry in multilayer dielectric waveguides as well as evanescent fields to strongly confine light in low-index materials. The proposed waveguide structures exhibit unusual light properties, such as uniform field distribution with a non-Gaussian spatial profile and scale invariance of the optical mode. This guiding mechanism is general and can be further extended to various optical structures, employed for different polarizations, and in different spectral regions. Therefore, our results can have huge implications for integrated photonics and related technologies.

Improved Thermal Stability and Oxygen‐Barrier Performance of SiO2 Thin Films by Modifying Amorphous Network Structure

“…In order to pursue more efficient light-matter interactions, low-refractive-index oxides with excellent stability are playing a critical role in numerous applications, ranging from conventional display [1,2] and communication [3] to emerging integrated nanophononics [4,5] and quantum photonics. [6] Among them, one typical demand is using low-index oxides as antireflective (AR) layers, which can significantly decrease the reflectance at air/film interface and improve the related optical devices' performance.…”