Electromagnetic fields in light waves are mainly transverse to propagation direction but actually also have longitudinal components, which may give rise to unexpected optical phenomena involving the angular momentum of light, such as transverse spin and optical torques.

中文翻译：

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纵向场和横向旋转

光波中的电磁场主要横向于传播方向，但实际上也具有纵向分量，这可能引起涉及光的角动量的意外光学现象，例如横向自旋和光学转矩。