Electromagnetically induced transparency, as a quantum interference effect to eliminate optical absorption in an opaque medium, has found extensive applications in slow-light generation, optical storage, frequency conversion, optical quantum memory and enhanced nonlinear interactions at the few-photon level in all kinds of systems. Recently, there has been great interest in exceptional points, a type of spectral singularity that could be reached by tuning various parameters in open systems, to render unusual features to the physical systems, such as optical states with chirality. Here we theoretically and experimentally study transparency and absorption modulated by chiral optical states at exceptional points in an indirectly coupled resonator system. By tuning one resonator to an exceptional point, transparency or absorption occurs depending on the chirality of the eigenstate. Our results demonstrate a new strategy to manipulate the light flow and the spectra of a photonic resonator system by exploiting a discrete optical state associated with a specific chirality at an exceptional point as a unique control bit. Such an approach is compatible with the state control utilized in quantum gate operation and may open up new avenues for controlling slow light using optical states for optical quantum memory and computing.

电磁感应透明性作为一种消除不透明介质中光吸收的量子干涉效应，已在各种慢光产生、光存储、频率转换、光量子记忆和增强的少数光子级非线性相互作用等方面得到广泛应用的系统。最近，人们对异常点产生了浓厚的兴趣，这是一种可以通过调整开放系统中的各种参数来达到的光谱奇点，从而为物理系统提供不寻常的特征，例如具有手性的光学状态。在这里，我们在理论上和实验上研究了间接耦合谐振器系统中特殊点处手性光学状态调制的透明度和吸收。通过将一个谐振器调整到一个特殊点，透明度或吸收取决于本征态的手性。我们的结果展示了一种新的策略，通过利用与特殊点处的特定手性相关的离散光学状态作为独特的控制位来操纵光子谐振器系统的光流和光谱。这种方法与量子门操作中使用的状态控制兼容，并可能为使用光学量子存储器和计算的光学状态控制慢光开辟新的途径。