Spiral-shaped microdisk lasers

Current-injection spiral-shaped microcavity disk laser diodes emitting in the ultraviolet (UV) are reported. We have previously demonstrated spiral microdisk lasers with InGaN multiple quantum well (MQW) gain media emitting near 400 nm and microresonators with an AlGaAs single quantum well (SQW) active regions emitting around 730 nm. In this paper we will extend this concept to UV emitting microdisk laser diodes and demonstrate room-temperature laser operation of InAlGaN heterostructures with emission wavelength near 368 nm and pulsed threshold current densities as low as 6.7 kA/cm2.