We investigate the interaction of laser pulses carrying orbital angular momentum (OAM) with a symmetry-broken ladder-type quantum coupling scheme involving three internal states. A weak probe beam acts on the lower leg of the ladder scheme, while a control beam of higher intensity drives the upper leg. In contrast to natural atoms, such a model with broken symmetry allows generating a sum-frequency signal beam between the most upper and lower quantum states, forming a cyclic closed-loop configuration of light-matter interaction. We propose situations for the efficient transfer of optical vortices to the generated signal beam via a nonlinear three-wave mixing process. It is demonstrated that the exchange process can occur both in the electromagnetically induced transparency (EIT) and the Autler-Townes splitting (ATS) regimes. The transition between the EIT and ATS conversion schemes can smoothly happen by simply tuning the knob of the control field. It is shown that the ATS regime is considerably more favorable than the EIT to achieve maximum energy conversion efficiency between light beams carrying the OAM. The results may provide an applications-based perspective to the ongoing research centered on vortex conversion-based comparisons between the ATS and EIT.

中文翻译：

---

对称破缺量子系统中的旋光交换

我们研究了携带轨道角动量 (OAM) 的激光脉冲与涉及三个内部状态的对称破坏梯型量子耦合方案的相互作用。弱探测光束作用于梯子方案的小腿，而更高强度的控制光束驱动大腿。与自然原子相比，这种对称性破缺的模型允许在最高量子态和最低量子态之间产生和频信号束，形成光-物质相互作用的循环闭环配置。我们提出了通过非线性三波混合过程将光涡流有效转移到生成的信号光束的情况。结果表明，交换过程可以发生在电磁感应透明 (EIT) 和奥特勒-汤斯分裂 (ATS) 制度中。EIT 和 ATS 转换方案之间的转换可以通过简单地调整控制字段的旋钮来平滑地发生。结果表明，ATS 机制比 EIT 更有利于实现携带 OAM 的光束之间的最大能量转换效率。这些结果可能为正在进行的以 ATS 和 EIT 之间基于涡流转换的比较为中心的研究提供基于应用的视角。