The micro-cavity lasers with different device sizes for the directional emission

Micro-cavity lasers have attracted more and more attention due to their low threshold, high cavity Q factor and being suitable for high density optoelectronic integration. However, the optical power output is very low due to total internal reflection of the whispering gallery modes WGMs, and their far-field profiles are isotropic due to isotropic micro-cavity structures. In this paper, we presented the limason-shaped cavity devices with different sizes for directional emission, and investigated their output characteristics in experiments. In experiment, mid-infrared quantum cascade lasers material was used to fabricate the micro-cavity lasers for its advantages for the micro-disk geometry due to their lack of surface recombination and inherently in-plane, transverse magnetic (TM) mode emission. By employing InP based InGaAs/InAlAs quantum cascade lasers material, the micro-cavity lasers are presented and investigated the output emission characteristics such as light output power, threshold current, and cavity quality Q factor.