Ultra-high Q alumina optical microresonators in the UV and blue bands

TL;DR

This paper reports the development of alumina-based optical microresonators with record-high quality factors in the UV and blue spectral bands, enabling advanced photonics applications.

Contribution

The study introduces ultra-low-loss alumina photonic microresonators with record Q factors in the UV and blue wavelengths, fabricated via scalable atomic layer deposition.

Findings

Achieved Q factor of 1.5×10^6 at 390nm

Achieved Q factor of 1.9×10^6 at 488.5nm

Demonstrated scalable fabrication process

Abstract

UV and visible photonics enable applications ranging from spectroscopic sensing to communication and quantum information processing. Photonics structures in these wavelength regimes, however, tend to experience higher loss than their IR counterpart. Particularly in the near-UV band, on-chip optical microresonators have not yet achieved a quality factor beyond 1 million. Here we report ultra-low-loss photonic waveguides and resonators patterned from alumina thin films prepared by a highly scalable atomic layer deposition process. We demonstrate ultra high Q factor of 1.5$\,\times\,$10$^6$ at 390nm, a record value at UV bands, and 1.9$\,\times\,$10$^6$ at 488.5nm.