基于Rudin-Shapiro(RS)非周期序列, 提出了一种能简易制作且可在轴向产生两个低色差图像的RS光子筛(RSPS)。基于角谱理论, 研究了光子筛筛孔的最小直径与对应波带片的最外环宽度的比值对RSPS聚焦特性的影响, 数值仿真结果表明, 当光子筛筛孔的最小直径是对应波带片最外环宽度的1.398倍时, RSPS能在轴向产生相同的高强度的双焦点。不同于RS波带片(RSZP)的环带结构, RSPS的孔状结构更容易制作。此外, 对比分析了RSPS、RSZP和Thue-Morse波带片(TMZP)的聚焦成像特性, 理论研究结果表明, RSPS在轴向两个焦平面产生的图像的色差比TMZP的色差低, 与RSZP的色差近似一样。因此, RSPS在多色成像, X射线显微等领域将具有广阔的应用前景。

A Rudin-Shapiro photon sieve (RSPS) based on the Rudin-Shapiro (RS) aperiodic sequence is proposed. The RSPS can be fabricated conveniently and generate two images with low chromatic aberration. The plane wave angular spectrum theory is used to study the focusing properties of the RSPSs with different ratios of the diameter of the smallest hole of the sieve to the width of the outermost ring of the corresponding zone plate. The numerical simulation results show that when the ratio is 1.398, the RSPS generates twin foci with the same high intensities in the axial direction. Compared with the RS zone plate (RSZP), the RSPS has more tolerance in the fabrication. It is found that the chromatic aberration generated by RSPS is lower than that by Thue-Morse zone plate (TMZP) and approximately the same as that by RSZP. Hence, the RSPS will have potential applications in the fields of the polychromatic imaging, X-ray microscopy and so on.