Whispering-gallery mode microdisk lasers

A new microlaser design based on the high-reflectivity whispering-gallery modes around the edge of a thin semiconductor microdisk is described and initial experimental results are presented. Optical confinement within the thin disk plane results in a microresonator with potential for single-mode, ultralow threshold lasers. Initial experiments use selective etching techniques in the InP/InGaAsP system to achieve 3–10 μm diameter disks as thin as 500 Å suspended in air or SiO2 on an InP pedestal. Optically pumped InGaAs quantum wells provide sufficient gain when cooled with liquid nitrogen to obtain single-mode lasing at 1.3 and 1.5 μm wavelengths with threshold pump powers below 100 μW.