Near-IR Subwavelength Microdisk Lasers

TL;DR

This paper demonstrates single-mode lasing in subwavelength GaAs microdisks fabricated via standard photolithography, achieving small disk sizes with whispering-gallery modes confirmed by simulations.

Contribution

It introduces a simple fabrication method for submicron GaAs disks that support single-mode lasing with whispering-gallery modes at subwavelength scales.

Findings

Disks as small as 627 nm in diameter lase under optical pumping.

Lasing modes are whispering-gallery modes with azimuthal number as low as 4.

The fabrication process yields disks with smooth boundaries and vertical sidewalls.

Abstract

We report single-mode lasing in subwavelength GaAs disks under optical pumping. The disks are fabricated by standard photolithography and two steps of wet chemical etching. The simple fabrication method can produce submicron disks with good circularity, smooth boundary and vertical sidewalls. The smallest lasing disks have a diameter of 627 nm and thickness of 265 nm. The ratio of the disk diameter to the vacuum lasing wavelength is about 0.7. Our numerical simulations confirm that the lasing modes are whispering-gallery modes with the azimuthal number as small as 4 and very small mode volume.