Heterostructure nanodisks for multicolor polariton lasers with controllable whispering-gallery modes.

Highly efficient optoelectronic devices of ultrasmall sizes are demanded as building blocks of next-generation integrated circuits, where tunable color enhances the feasibility of various applications. Here, we realize tunable multicolor nanolasers using disk-shaped axial heterostructures composed of III-nitride materials (GaN/InGaN/GaN), leveraging the optical confinement effect and active waveguiding. In heterostructure nanodisks, the development of exciton-polariton induces unique features near the resonance regime, and the formation of whispering-gallery modes facilitates optical gain processes for the polaritonic lasing of GaN. Likewise, the polaritonic lasing of InGaN emerges, although the small gain volume in the quantum well structure hinders strong amplification. Notably, the characteristics of lasing differ between GaN and InGaN, suggesting a distinctive polariton behavior in quantum well structures. The alloyed systems enable tunable laser colors in the visible region, while whispering-gallery modes afford independent control of lasing. Therefore, we establish tunable dual-color polariton nanolasers using heterostructure disks for the first time, achieving nanophotonic devices that take advantage of the optical confinement effect and active waveguiding.