ABSTRACT We present a theoretical model to realize the symmetric and asymmetric diffraction grating in a four-level atomic medium. The proposed atomic medium follows a double lambda configuration where four fields interact with it. We get control over symmetric and asymmetric behavior of the diffraction grating by manipulating the relative phase of the fields. Interestingly, the symmetric and asymmetric diffraction grating become prominent when the vortex beam is used instead of the plane wave. Enhanced first, second, and third-order diffraction gratings are achieved via the vortex beam. Further, we find control over asymmetric diffraction gratings by the relative phase of the fields. Coherent control of asymmetric diffraction grating in negative and positive diffracted angles is also achieved via the relative phase.

中文翻译：

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通过相对相位对对称和非对称衍射光栅进行相干控制

摘要 我们提出了在四能级原子介质中实现对称和非对称衍射光栅的理论模型。提议的原子介质遵循双 lambda 配置，其中四个场与其相互作用。我们通过操纵场的相对相位来控制衍射光栅的对称和非对称行为。有趣的是，当使用涡旋光束代替平面波时，对称和非对称衍射光栅变得突出。通过涡旋光束实现增强的一阶、二阶和三阶衍射光栅。此外，我们发现通过场的相对相位控制非对称衍射光栅。负衍射角和正衍射角的非对称衍射光栅的相干控制也是通过相对相位实现的。