Optimal photonic crystal cavities for coupling nanoemitters to photonic integrated circuits

TL;DR

This paper demonstrates the design and fabrication of high-quality photonic crystal nanobeam cavities for visible wavelengths, enabling efficient coupling of quantum emitters to integrated photonic circuits on silicon chips.

Contribution

It introduces a method for creating on-substrate photonic crystal nanobeam cavities with high quality factors suitable for visible quantum emitters, comparing design approaches.

Findings

Mode-matching design method is advantageous for on-substrate fabrication.

High quality factors and small mode volumes achieved in visible spectrum.

Facilitates integration of quantum emitters with nanophotonic circuits.

Abstract

Photonic integrated circuits that are manufactured with mature semiconductor technology hold great promise for realizing scalable quantum technology. Efficient interfaces between quantum emitters and nanophotonic devices are crucial building blocks for such implementations on silicon chips. These interfaces can be realized as nanobeam optical cavities with high quality factors and wavelength-scale mode volumes, thus providing enhanced coupling between nanoscale quantum emitters and nanophotonic circuits. Realizing such resonant structures is particularly challenging for the visible wavelength range, where many of the currently considered quantum emitters operate, and if compatibility with modern semiconductor nanofabrication processes is desired. Here we show that photonic crystal nanobeam cavities for the visible spectrum can be designed and fabricated directly on-substrate with high quality factors and small mode volumes. We compare designs based on deterministic and mode-matching methods and find the latter advantageous for on-substrate realizations. Our results pave the way for integrating quantum emitters with nanophotonic circuits for applications in quantum technology.