Quantization of mode shifts in nanocavities integrated with atomically thin sheets

TL;DR

This paper demonstrates how integrating atomically thin two-dimensional materials with silicon nanocavities enables giant, quantized shifts in resonance, paving the way for reconfigurable photonic devices with enhanced responsivity.

Contribution

It introduces a novel cavity design that leverages 2D materials for quantized mode shifts and provides detailed analysis of dielectric properties across different layer thicknesses.

Findings

Giant, quantized shifts of resonant wavelength achieved with 2D materials.

Dielectric constant of flakes is layer-independent down to monolayer.

Reconfigurable cavities demonstrated by stacking and removing ultrathin flakes.

Abstract

The unique optical properties of two-dimensional layered materials are attractive for achieving increased functionality in integrated photonics. Owing to the van der Waals nature, these materials are ideal for integrating with nanoscale photonic structures. Here we report on carefully designed air-mode silicon photonic crystal nanobeam cavities for efficient control through two-dimensional materials. By systematically investigating various types and thickness of two-dimensional materials, we are able to show that enhanced responsivity allows for giant shifts of the resonant wavelength. With atomically precise thickness over a macroscopic area, few-layer flakes give rise to quantization of the mode shifts. We extract the dielectric constant of the flakes and find that it is independent of the layer number down to a monolayer. Flexible reconfiguration of a cavity is demonstrated by stacking and removing ultrathin flakes. With an unconventional cavity design, our results open up new possibilities for photonic devices integrated with two-dimensional materials.