We study the orbital angular momentum (OAM) transfer from a weak Laguerre-Gaussian (LG) field to a weak plane-wave in two closed-loop three-level $V$-type atomic systems. In the first scheme, the atomic system has two non-degenerate upper levels which the corresponding transition is excited by a microwave plane-wave. It is analytically shown that the microwave field induces an OAM transfer from an LG field to a generated third field. In the second scheme, we consider a three-level $V$-type atomic system with two near-degenerate excited states and study the effect of the quantum interference due to the spontaneous emission on the OAM transfer. It is found that the spontaneously generated coherence (SGC) induces the OAM transfer from the LG field to the weak planar field, while the OAM transfer does not occur in the absence of the SGC. The suggested models prepare a rather simple method for the OAM transfer which can be used in quantum information processing and data storage.
A unified matrix representation for spin and orbital angular momentum in partially coherent beams
一个矩阵表示引入静止的光束状光场，允许同时治疗的轨道角动量（OAM）和空间相干性的二阶状态。该相干-OAM矩阵是笛卡尔偏振基中的2 X 2光束相干-偏振矩阵或圆偏振基中的相干-自旋角动量（SAM）矩阵的对应物。讨论了相干-OAM矩阵的一般性质，并引入相干-SAM-OAM矩阵作为处理具有任意相干、自旋和轨道角动量态光束的统一实体。
