Junghyun Sung Joohoon Kim Ho Seung Lee Woo Hun Choi Minsu Jeong Jihae Lee Seokwoo Kim Dong-Jin Shin Daegwang Choi Junsuk Rho Su-Hyun Gong Song, Hyun Gyu 2026-02-19T01:00:17Z 2026-02-19T01:00:17Z 2025-11-20 2026-02 https://pubs.kist.re.kr/handle/201004/154266 While most approaches to polariton research focus on achieving strong coupling between excitons in monolayer transition metal dichalcogenides (TMDCs) and external microcavities, bulk TMDCs have been largely overlooked due to their reduced exciton oscillator strength and indirect bandgap nature. Here, we report the observation of polariton condensation within the indirect-transition range, enabled by a condensation mechanism in 50-nm-thick WS₂-based bound state in the continuum (BIC) cavities. Our photonic-like BIC polaritons exhibit a significant Rabi splitting energy ( ~ 294 meV) and clear evidence of condensation driven by a mechanism involving indirect excitons that directly inject photons into BIC polaritons. Remarkably, the interaction-induced confinement of polariton condensates can be optically tuned by adjusting the pump laser size, despite a minimal exciton fraction of 6%, distinguishing this system from purely photonic counterparts. These findings open new avenues for exploring polariton physics with indirect excitons in TMDCs and other emerging materials. English Nature Publishing Group Polariton condensate far-detuned from exciton resonance in WS2 bound states in the continuum Article 10.1038/s41467-025-67454-5 1 Nature Communications, v.17 Nature Communications 17 Y scie scopus 001683207800001 Multidisciplinary Sciences Science & Technology - Other Topics Article