We analyze azimuthal modulation of probe field absorption profile in a closed four-level inverted Y-type atomic system. We employ a Laguerre–Gaussian beam and a microwave field to realize spatially varying atomic susceptibility, which is responsible for the generation of structured light. An extra nonvortex control beam is used to ensure electromagnetically induced transparency at the core of Laguerre–Gaussian beam. Our proposed model exhibits both absorption and gain at different azimuthal angles, and orbital angular momentum of light can be identified via absorption profile of the probe field. We further discuss the transfer of optical vortices from Laguerre–Gaussian beam to the transmitted probe field.

中文翻译：

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探针对光涡旋的吸收和转移的方位角调制

我们分析了封闭的四能级倒Y型原子系统中探针场吸收分布的方位角调制。我们采用拉盖尔-高斯光束和微波场来实现空间变化的原子磁化率，这是结构光的产生的原因。额外的非涡旋控制光束用于确保Laguerre–Gaussian光束核心的电磁感应透明性。我们提出的模型在不同的方位角上都表现出吸收和增益，并且可以通过探测场的吸收轮廓来识别光的轨道角动量。我们进一步讨论了光学涡旋从拉盖尔-高斯光束到透射探针场的转移。