Long-wavelength InAs/InAlGaAs quantum dot microdisk lasers on InP (001) substrate

In this Letter, we present long-wavelength microdisk lasers based on five stacks of self-assembled InAs/InAlGaAs quantum dots as the active medium, which were grown on InP (001) substrate by solid-source molecular beam epitaxy. The 8.4-mu m-diameter quantum dot microdisk laser is operated at room temperature under pulsed optically pumping conditions. Multi-wavelength lasing emissions at similar to 1.6 mu m were achieved with a low lasing threshold of 30 mu W and a quality factor of similar to 1336. The lasing behavior was verified by the "S " shape L-L curve, linewidth narrowing effect, and strong speckle patterns of the collected near field intensity profile. The demonstrated long-wavelength lasers with low threshold and ultracompact footprint can find potential applications in integrated gas detection and highly localized label-free biological and biochemical sensing.