When particles with integer spin accumulate at low temperature and high density, they undergo Bose–Einstein condensation (BEC). Atoms, magnons, solid-state excitons, surface plasmon polaritons and excitons coupled to light exhibit BEC, which results in high coherence due to massive occupation of the respective system’s ground state. Surprisingly, photons were shown to exhibit BEC recently in organic-dye-filled optical microcavities, which—owing to the photon’s low mass—occurs at room temperature. Here we demonstrate that photons within an inorganic semiconductor microcavity also thermalize and undergo BEC. Although semiconductor lasers are understood to operate out of thermal equilibrium, we identify a region of good thermalization in our system where we can clearly distinguish laser action from BEC. Semiconductor microcavities are a robust system for exploring the physics and applications of quantum statistical photon condensates. In practical terms, photon BECs offer their critical behaviour at lower thresholds than lasers. Our study shows two further advantages: the lack of dark electronic states in inorganic semiconductors allows these BECs to be sustained continuously; and quantum wells offer stronger photon–photon scattering. We measure an unoptimized interaction parameter (\(\tilde{{{{{g}}}}}\) ≳ 10^–3), which is large enough to access the rich physics of interactions within BECs, such as superfluid light.

当具有整数自旋的粒子在低温和高密度下聚集时，它们会发生玻色-爱因斯坦凝聚（BEC）。原子、磁振子、固态激子、表面等离激元极化激元和与光耦合的激子表现出 BEC，由于大量占据各自系统的基态而导致高相干性。令人惊讶的是，光子最近在有机染料填充的光学微腔中表现出 BEC，由于光子质量低，这种现象在室温下发生。在这里，我们证明无机半导体微腔内的光子也会热化并经历 BEC。尽管半导体激光器被认为是在热平衡状态下工作的，但我们在系统中发现了一个良好热化的区域，在这里我们可以清楚地区分激光作用与 BEC。半导体微腔是用于探索量子统计光子凝聚物的物理和应用的强大系统。实际上，光子 BEC 在比激光更低的阈值下提供关键行为。我们的研究显示了另外两个优势：无机半导体中缺乏暗电子态使得这些 BEC 能够持续持续；量子阱提供更强的光子-光子散射。我们测量了一个未优化的相互作用参数 ( \(\tilde{{{{{g}}}}}\) ≳ 10 ^–3 )，该参数足够大，足以访问 BEC 内丰富的相互作用物理特性，例如超流光。