The hybridization of light and matter excitations in the form of polaritons has enabled major advances in understanding and controlling optical nonlinearities. Entering the quantum regime of strong interactions between individual photons has, however, remained challenging since the strength of achievable polariton interactions is typically limited by the available interactions in the material. Here, we investigate collisions between dark-state polaritons in three-level systems and discover a resonant process that yields effective interactions, which are much larger than the underlying interaction between their matter constituents. We systematically investigate the underlying mechanism and demonstrate a substantial enhancement of polariton interactions by several orders of magnitude. This suggests a promising approach to quantum nonlinear optics in a range of physical settings, from atomic gases to excitons in semiconductors and two-dimensional bilayer materials.

中文翻译：

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来自弱相互作用粒子的强光子相互作用

极化子形式的光和物质激发的混合使得理解和控制光学非线性取得了重大进展。然而，进入单个光子之间强相互作用的量子体系仍然具有挑战性，因为可实现的极化子相互作用的强度通常受到材料中可用相互作用的限制。在这里，我们研究了三能级系统中暗态极化子之间的碰撞，并发现了一个产生有效相互作用的共振过程，该相互作用远大于其物质成分之间的潜在相互作用。我们系统地研究了潜在的机制，并证明了极化子相互作用显着增强了几个数量级。