Many bosons can occupy a single quantum state without a limit. It is described by the quantum-mechanical Bose–Einstein statistic, which allows Bose–Einstein condensation at low temperatures and high particle densities. Photons, historically the first considered bosonic gas, were late to show this phenomenon, observed in rhodamine-filled microcavities and doped fibre cavities. These findings have raised the question of whether condensation is also common in other laser systems with potential technological applications. Here we show the Bose–Einstein condensation of photons in a broad-area vertical-cavity surface-emitting laser with a slight cavity-gain spectral detuning. We observed a Bose–Einstein condensate in the fundamental transversal optical mode at a critical phase-space density. The experimental results follow the equation of state for a two-dimensional gas of bosons in thermal equilibrium, although the extracted spectral temperatures were lower than the device’s. This is interpreted as originating from the driven-dissipative nature of the photon gas. In contrast, non-equilibrium lasing action is observed in the higher-order modes in more negatively detuned device. Our work opens the way for the potential exploration of superfluid physics of interacting photons mediated by semiconductor optical nonlinearities. It also shows great promise for enabling single-mode high-power emission from a large-aperture device.

许多玻色子可以无限制地占据单个量子态。它由量子力学玻色-爱因斯坦统计来描述，该统计允许玻色-爱因斯坦在低温和高粒子密度下凝结。光子，历史上第一个被认为是玻色子气体，很晚才显示出这种现象，在充满罗丹明的微腔和掺杂光纤腔中观察到。这些发现提出了一个问题：冷凝在其他具有潜在技术应用的激光系统中是否也很常见。在这里，我们展示了大面积垂直腔表面发射激光器中光子的玻色-爱因斯坦凝聚，具有轻微的腔增益光谱失谐。我们在临界相空间密度下观察到基本横向光学模式的玻色-爱因斯坦凝聚态。尽管提取的光谱温度低于设备的光谱温度，但实验结果遵循处于热平衡状态的二维玻色子气体的状态方程。这被解释为源于光子气体的驱动耗散性质。相反，在负失谐装置的高阶模式中观察到非平衡激光作用。我们的工作为半导体光学非线性介导的相互作用光子的超流体物理的潜在探索开辟了道路。它还显示出从大孔径器件实现单模高功率发射的巨大前景。