激光光束空间低通滤波技术是提高光束空域质量的重要手段之一。随着高能激光技术的进一步发展，传统的针孔滤波技术因其对光束的聚焦特性，已逐渐成为限制高能激光光束空域质量提高的瓶颈，因此，不对光束聚焦即可实现光束空域质量的改善成为突破该瓶颈的创新型技术。体光栅、多层介质薄膜、Rugate薄膜和光子晶体因具有良好的波矢选择特性，已成为当前实现非聚焦型光束空间低通滤波的主流技术和研究热点。分别从这4种光学元件入手，简要分析了体光栅的布拉格衍射特性、多层介质薄膜和Rugate薄膜对光束的相长相消干涉特性，以及利用光子晶体的自准直效应来实现非聚焦型光束空间低通滤波的主要技术特点，综述了这4种技术在光束空间低通滤波应用中的研究进展。和针孔滤波技术的聚焦特性相比，这4种技术的非聚焦滤波特性具有取代针孔滤波的可行性，尤其是在对高功率激光进行空间低通滤波的应用中。

Low-pass spatial filtering for laser beams plays a key role in improving spatial quality of beams. With the development of high power laser beams, the traditional pinhole spatial filtering becomes a bottleneck to enhance the beam spatial quality, due to its focusing characteristics. Low-pass spatial filtering without focusing is an innovative technique, which can break the bottleneck and improve the spatial quality of beams. Volume grating, multi-layer film, Rugate coating, and photonic crystal have been the main techniques and research focuses to realize the non-focusing spatial filtering for laser beams because of their fine wave vector selectivity. Bragg diffraction of volume grating, constructive and destructive interference of multi-layer and Rugate coatings, and self-collimating of photonic crystal are described to analyze their spatial filtering performance, respectively. The research status of these four techniques for spatial filtering is reviewed. The four techniques can be a substitute for pinhole spatial filtering, especially in the field of high power laser beams.