Hybrid Ultrahigh-Quality Etchless Microcavity for Applications with Low-Dimensional Materials

Abstract

Two-dimensional (2D) materials possess exceptional optical properties, holding great potential for the development of advanced linear and nonlinear optoelectronic devices. However, their efficient integration into photonic circuits remains challenging due to the trade-off between low-loss transmission and strong light–matter interaction. Here, we present an etchless platform utilizing a weakly index-guided transverse electric (TE) mode. This approach achieves low transmission loss and high modal overlap with 2D materials simultaneously, while removing the constrains on the waveguide width in device design. Using this platform, we successfully demonstrate two types of ultrahigh-quality (Q) resonators integrated with 2D materials, i.e., microring resonators (MRRs) and Bragg grating Fabry-Pérot (FP) cavities, with intrinsic Q factors exceeding one million. Measurements show clear resonance shifts, indicating effective light–matter interaction with 2D materials, while achieving trivial Q degradation for flakes with a thickness below 10 nm. We further characterize the third-order nonlinear response of 2D materials using the proposed platform. This work establishes a simple and flexible platform for high-performance 2D material-based devices like modulators, detectors, and quantum light sources.