针对美国劳伦斯·利弗莫尔国家实验室所提出的四柱透镜结构的线聚焦型空间滤波器(线型滤波器)，根据瑞利-索末菲衍射积分和利用Matlab 软件对光束在线型滤波器中的传输进行了理论模拟研究，得到了线型滤波器的像传递模式并对其空间滤波功能进行了对比研究。与传统的针孔滤波器不同，线型滤波器的系统前后焦面并不只与透镜焦距有关，还与柱面镜在x 和y 方向错开的距离相关，其优点是能将高功率激光装置中的远场强度降低约3个数量级，从而大大减小滤波器规模，但同时也带来一个不足之处，即线型滤波器只能在1 倍口径匹配条件下满足严格的像传递功能。在1倍口径匹配条件下，线型滤波器的空间滤波功能与传统针孔滤波器也是一致的。

Based on the four-cylindrical-lens slit spatial filter proposed by American Lawrence Livermore National Laboratory, the beam propagation characteristics in the slit spatial filter has been studied with Rayleigh-Sommerfeld diffraction integral and commercial Matlab software on image relay and spatial filtering. Unlike the conventional pinhole spatial filter, the front (back) focal plane of the slit spatial filter system is not only related with focal length, but also with the distance between the cylindrical lenses, which is beneficial for greatly decreasing the focal intensity in high-power lasers by about 3 orders of magnitudes and greatly decreasing the scale of the spatial filter. However, with the slit spatial filter, negative point is also brought about that, the image relay of slit spatial filter can be strict satisfied only in the situation of 1 time beam expansion. In the situation of 1 times beam expansion, the spatial filtering of the slit spatial filter is consistent with the conventional pinhole spatial filter.