Room‐Temperature Polariton Condensation Into Superscar Modes in Growth‐Defined Triangular Micro‐Prism Resonators

ABSTRACT

Group III‐nitride semiconductors are regarded as key materials for realizing polariton devices operating at room‐temperature owing to their high oscillator strength and wide bandgap energies. However, in conventional platforms based on distributed Bragg reflectors, photonic crystals, and hexagonal rod resonators, it remains challenging to simultaneously achieve the high Q‐factors and large Rabi splitting required for polariton‐based research. Here, we realize a high Q ‐factor (∼1700) superscar mode in a freestanding triangular micro‐prism structure via direct bottom‐up growth, and achieve exciton‐polariton condensation with large Rabi splitting at room‐temperature. Selective area growth enables micro‐prism cavities with high‐quality exciton generation through threading dislocation blocking. Notably, for microcavities of comparable size, this architecture supports high‐ Q superscar modes that exhibit Q ‐factors at least an order of magnitude higher than conventional whispering gallery modes, without requiring complex post‐processing. In addition, a large Rabi splitting energy (∼114.6 meV) was achieved owing to the high spatial overlap between the electric field and the active medium. By realizing high‐Q‐factor room‐temperature polariton condensation with large Rabi splitting beyond the capabilities of conventional resonators, we have established a new platform that simultaneously supports low condensation thresholds and large coupling strength, both of which are critical for polariton research at room‐temperature.