Choi Seou, Salamin Yannick, Roques-Carmes Charles, Sloan Jamison, Horodynski Michael, Soljačić Marin
Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA.
Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
Nat Commun. 2025 Aug 14;16(1):7576. doi: 10.1038/s41467-025-63035-8.
Observing non-classical properties of light is a long-standing interest to advance a wide range of quantum applications. Optical cavities are essential to generate and manipulate non-classical light. However, detecting changes in cavity properties induced by the quantum state remains a critical challenge in the optical domain due to the weak material nonlinearity. Here, we propose a framework for observing the dynamics of quantum states generated inside nonlinear optical cavities. We leverage the symmetry-breaking process of a bistable system, which is highly sensitive to the initial state, enabling detection of quantum state displacement through an asymmetric equilibrium of a macroscopic observable. With a nonlinear response at the single photon level, our approach directly imprints the cavity field distribution onto the statistics of bistable cavity steady-states. We experimentally demonstrate our approach in a degenerate optical parametric oscillator, generating and reconstructing different quantum states. As a validation, we reconstruct the Husimi Q function of the cavity squeezed vacuum state. In addition, we observe the evolution of the quantum vacuum state inside the cavity as it undergoes phase-sensitive amplification. By enabling generation and measurement of quantum states in a single nonlinear optical cavity, our method paves a way for studying exotic dynamics of quantum optical states in nonlinear driven-dissipative systems.
观察光的非经典特性一直是推动广泛量子应用的长期兴趣所在。光学腔对于产生和操纵非经典光至关重要。然而，由于材料非线性较弱，检测由量子态引起的腔特性变化在光学领域仍然是一个关键挑战。在此，我们提出了一个用于观察非线性光学腔内产生的量子态动力学的框架。我们利用双稳系统的对称破缺过程，该过程对初始状态高度敏感，能够通过宏观可观测量的不对称平衡来检测量子态位移。由于在单光子水平上具有非线性响应，我们的方法直接将腔场分布印刻到双稳腔稳态的统计数据上。我们在简并光学参量振荡器中通过实验证明了我们的方法，生成并重构了不同的量子态。作为验证，我们重构了腔压缩真空态的胡西米Q函数。此外，我们观察了腔内量子真空态在经历相敏放大时的演化。通过在单个非线性光学腔中实现量子态的产生和测量，我们的方法为研究非线性驱动耗散系统中量子光学态的奇异动力学铺平了道路。
