With two sets of standing-wave fields built in a thermal rubidium vapor cell, we have established a controllable photonic crystal with periodic gain in a coherently prepared $N$-type four-level atomic configuration. First, the photonic lattice constructed by a resonant standing-wave coupling field results in a spatially modulated susceptibility and makes the signal field diffract in a discrete manner under the condition of electromagnetically induced transparency. Then, with the addition of the standing-wave pump field, the $N$-type atomic medium can induce a periodic Raman gain on the signal field, which can be effectively controlled by tuning the pertinent atomic parameters. The experimental demonstration of such a real-time reconfigurable photonic crystal structure with periodic Raman gain can pave the way for realizing desired applications predicted in the gain-modulated periodic optical systems.

中文翻译：

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相干原子介质中具有周期性拉曼增益的可控光子晶体

在热rub蒸气池中建立了两组驻波场，我们在相干制备的过程中建立了具有周期性增益的可控光子晶体 $ñ$型四级原子配置。首先，由共振驻波耦合场构成的光子晶格导致空间调制的磁化率并使信号场在电磁感应的透明性条件下以离散方式衍射。然后，加上驻波泵浦场，$ñ$型原子介质可以在信号场上引起周期性的拉曼增益，可以通过调整相关的原子参数来有效地控制这种增益。具有周期性拉曼增益的这种实时可重构光子晶体结构的实验演示可以为实现在增益调制的周期性光学系统中预测的所需应用铺平道路。