Digital resonance tuning of high-Q/Vm silicon photonic crystal nanocavities by atomic layer deposition

TL;DR

This paper introduces a precise, post-fabrication method for tuning high-Q silicon photonic nanocavities using atomic layer deposition, enabling discrete, controllable resonance shifts while preserving cavity quality.

Contribution

It demonstrates a novel digital resonance tuning technique for silicon photonic nanocavities using atomic layer deposition, maintaining high quality factors over a broad tuning range.

Findings

Resonance can be tuned in discrete steps of 122 +/- 18 pm per hafnium oxide layer.

The tuning process is nearly linear over a 17 nm range.

Cavity Q is preserved and can reach initial high values of 49,000 or more.

Abstract

We propose and demonstrate the digital resonance tuning of high-Q/Vm silicon photonic crystal nanocavities using a self-limiting atomic layer deposition technique. Control of resonances in discrete steps of 122 +/- 18 pm per hafnium oxide atomic layer is achieved through this post-fabrication process, nearly linear over a full 17 nm tuning range. The cavity Q is maintained in this perturbative process, and can reach up to its initial values of 49,000 or more. Our results are highly controllable, applicable to many material systems, and particularly critical to matching resonances and transitions involving mesoscopic optical cavities.