Low-pass spatial filters (LPSFs) have been broadly applied to image enhancement and information processing in several regions of the electromagnetic spectrum,particularly,but not solely,in optical spectroscopy.[1,2] The conventional technique of lowpass spatial filtering uses a telescope system to form a far-field image and blocks the undesired high-spatial frequency components with an appropriate pinhole in the focal plane.This system,although widely used,has several inconveniences,such as a relatively large volume,the absence of efficient focusing lenses in nearinfrared frequency,and so on.[3-6] So far,some mode spatial filters have been proposed for the purpose of overcoming the disadvantages of conventional spatial filters.However,these spatial filters,based on the resonant grating system,[7,8] multilayer stacks combined with a prism,[9] and two-dimensional (2D)photonic crystals (PCs),[6,10-13] are only used as onedimensional (1D) spatial filters.