Photonic crystals to enhance light extraction from 2D materials

TL;DR

This paper presents a photonic crystal cavity design that significantly improves light extraction efficiency from 2D materials by optimizing cavity coupling and directionality, achieving over threefold enhancement in emission extraction.

Contribution

It introduces a novel cavity design based on defective rod photonic crystals and demonstrates how height profiling of 2D materials enhances exciton-cavity coupling and light extraction.

Findings

Extraction ratio increased by a factor of 3.4 with the photonic structure.

Optimal rod radius for maximum enhancement is 0.165 times the lattice constant.

Adjusting rod radius and 2D material height affects flux spectrum and coupling efficiency.

Abstract

We propose a scheme for coupling 2D materials to an engineered cavity based on a defective rod type photonic crystal lattice. We show results from numerical modelling of the suggested cavity design, and propose using the height profile of a 2D material transferred on top of the cavity to maximise coupling between exciton recombination and the cavity mode. The photonic structure plays a key role in enhancing the launch efficiency, by improving the directionality of the emitted light to better couple it into an external optical system. When using the photonic structure, we measured an increase in the extraction ratio by a factor of 3.4. We investigated the variations in the flux spectrum when the radius of the rods is modified, and when the 2D material droops to a range of different heights within the cavity. We found an optimum enhancement when the rods have a radius equal to 0.165 times the lattice constant, this enhancement reduces when the radius is reduced or increased. Finally, we discuss the possible use of solid immersion lenses, in combination with our photonic structure, to further enhance the launch efficiency and to improve vertical confinement of the cavity mode.