Grating structure

The invention provides a grating structure. The grating structure includes: a substrate structure; and a grating layer which is of a periodic structure, the grating in each period serves as a sub-grating, wherein the multiple sub-gratings are arranged on one side of the substrate structure at intervals, each sub-grating is of a rectangular structure and is of an asymmetric structure, and the period of the grating structure is smaller than 1.5 times of the incident center wavelength. The polarization beam splitter solves the problem that the dispersion capabilities of +/-1- level diffraction light in different polarization states are different in the polarization beam splitter in the prior art. 本发明提供了一种光栅结构。光栅结构包括：基底结构；光栅层，光栅层为周期结构，每个周期内的光栅作为一个子光栅，多个子光栅间隔设置在基底结构的一侧，子光栅为矩形结构，且子光栅为非对称结构，光栅结构的周期小于1.5倍入射中心波长。本发明解决了现有技术中偏振分束器件存在不同偏振状态的±1级衍射光的色散能力不同的问题。