A 1.16-{\mu}m-radius disk cavity in a sunflower-type circular photonic crystal with ultrahigh quality factor

TL;DR

This paper demonstrates a sunflower-type circular photonic crystal embedded disk cavity with a radius of 1.16 micrometers achieving ultrahigh quality factors, significantly surpassing bare disk performance due to band gap induced reduction in bending loss.

Contribution

The work introduces a novel sunflower-type CPC design that enhances Q factors in small disk cavities, with experimental validation on silicon-on-insulator substrates.

Findings

Simulated Q of 10^7 for the designed cavity.

Experimental loaded Q of 7.4 × 10^5 achieved.

Record high Q for such small disk cavities.

Abstract

We present a 1.16-\mum-radius disk cavity with ultrahigh quality (Q) factor by embedding the disk into a sunflower-type circular photonic crystal (CPC). The band gap of the CPC reduces the bending loss of the whispering-gallery mode of the disk, leading to a simulated Q of 10^7, at least one order of magnitude higher than a bare disk of the same size. The design is experimentally verified with a record high loaded Q of 7.4 \times 10^5 measured from an optimized device fabricated on a silicon-on-insulator substrate.