Femtosecond laser-written nano-ablations containing bright antibunched emitters on gallium nitride

TL;DR

This paper demonstrates a femtosecond laser-writing technique to create ordered arrays of bright, antibunched quantum emitters in gallium nitride, enabling deterministic nanofabrication for quantum photonics.

Contribution

It introduces a novel femtosecond laser fabrication method for ordered quantum emitters in GaN, overcoming randomness in traditional epitaxial growth.

Findings

Emitters exhibit MHz antibunched emission at room temperature.

Laser-written nano-ablations enable deterministic placement of quantum emitters.

Rapid thermal annealing activates stable quantum emitters in GaN.

Abstract

Femtosecond laser-writing offers distinct capabilities for fabrication, including three-dimensional, multi-material, and sub-diffraction-limited patterning. In particular, demonstrations of laser-written quantum emitters and photonic devices with superior optical properties have attracted attention. Recently, gallium nitride (GaN) has been reported to host quantum emitters with narrow and bright zero-phonon photoluminescence from ultraviolet to telecom ranges. However, emitters formed during epitaxy are randomly positioned, and until now, it has not been possible to fabricate quantum emitters in ordered arrays. In this paper, we employ femtosecond laser writing to create nano-ablations with sub-diffraction-limited diameter, and use rapid thermal annealing to activate co-located stable emitters. The emitters show MHz antibunched emission with a sharp spectral peak at room temperature. Our study not only presents an efficient approach to laser-written nanofabrication on GaN but also offers a promising pathway for the deterministic creation of quantum emitters in GaN, shedding light on the underlying mechanisms involved.