Toward Arbitrary Spin‐Orbit Flat Optics Via Structured Geometric Phase Gratings
Toward Arbitrary Spin‐Orbit Flat Optics Via Structured Geometric Phase Gratings
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DOI：
10.1002/lpor.202200800
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发表时间：
2023-01
影响因子：
11
通讯作者：
Chunyu Li;Si‐Jia Liu;B. Yu;Hai-jun Wu;Carmelo Rosales-Guzm'an;Yijie Shen;Peng Chen;Zhichao Zhu;Yan‐Qing Lu
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文献类型：
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作者：
Chunyu Li;Si‐Jia Liu;B. Yu;Hai-jun Wu;Carmelo Rosales-Guzm'an;Yijie Shen;Peng Chen;Zhichao Zhu;Yan‐Qing Lu
通过几何相位与平面光学器件的相互自旋轨道耦合（SOC）为成形和控制近轴结构光提供了一个有前途的平台。目前的设备，从开创性的q板到最近的J板，只提供自旋相关的波前调制，而没有振幅控制。然而，实现对傍轴SOC状态的所有空间维度的控制需要对相应的复振幅进行自旋相关控制，这对于平面光学器件仍然具有挑战性。在这里，为了解决这个问题，提出了一种称为结构化几何相位光栅的新型平面光学元件，其能够对正交输入圆偏振进行共轭复振幅控制。通过使用微结构液晶光配向技术，设计了一系列平面光学元件，并展示了它们在任意SOC控制中的出色精度。这一原理通过平面光学解锁了近轴结构光的全场控制，为开发一般光子SOC态的信息交换和处理单元以及用于高精度激光束整形的腔外/腔内模式转换器提供了一种有前途的方法。
Reciprocal spin‐orbit coupling (SOC) via geometric phase with flat optics provides a promising platform for shaping and controlling paraxial structured light. Current devices, from the pioneering q‐plates to the recent J‐plates, provide only spin‐dependent wavefront modulation without amplitude control. However, achieving control over all the spatial dimensions of paraxial SOC states requires spin‐dependent control of corresponding complex amplitude, which remains challenging for flat optics. Here, to address this issue, a new type of flat‐optics elements termed structured geometric phase gratings is presented, that is capable of conjugated complex‐amplitude control for orthogonal input circular polarizations. By using a microstructured liquid crystal photoalignment technique, a series of flat‐optics elements is engineered and their excellent precision in arbitrary SOC control is shown. This principle unlocks the full‐field control of paraxial structured light via flat optics, providing a promising way to develop an information exchange and processing units for general photonic SOC states, as well as extra‐/intracavity mode convertors for high‐precision laser beam shaping.