Redmann Andreas, Kurtscheid Christian, Wolf Niels, Vewinger Frank, Schmitt Julian, Weitz Martin
Institut für Angewandte Physik, <a href="https://ror.org/041nas322">Universität Bonn</a>, Wegelerstrasse 8, 53115 Bonn, Germany.
Phys Rev Lett. 2024 Aug 30;133(9):093602. doi: 10.1103/PhysRevLett.133.093602.
Thermalization of radiation by contact to matter is a well-known concept, but the application of thermodynamic methods to complex quantum states of light remains a challenge. Here, we observe Bose-Einstein condensation of photons into the hybridized ground state of a coupled four-site ring potential. In our experiment, the periodically closed ring lattice superimposed by a weak harmonic trap for photons is realized inside a spatially structured dye-filled microcavity. Photons thermalize to room temperature, and above a critical photon number macroscopically occupy the symmetric linear combination of the site eigenstates with zero phase winding, which constitutes the ground state of the system. The mutual phase coherence of photons at different lattice sites is verified by optical interferometry.
通过与物质接触使辐射热化是一个众所周知的概念，但将热力学方法应用于复杂的光量子态仍然是一个挑战。在这里，我们观察到光子的玻色-爱因斯坦凝聚进入耦合四格点环形势的杂化基态。在我们的实验中，在一个空间结构化的充满染料的微腔内实现了由弱谐波陷阱叠加的周期性闭合环形晶格，用于捕获光子。光子热化到室温，并且在临界光子数以上，宏观上占据具有零相位缠绕的格点本征态的对称线性组合，这构成了系统的基态。通过光学干涉测量验证了不同晶格位置处光子的相互相位相干性。
