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    • 摘要: 切趾在成像和光通信领域得到了重要的应用。传统的切趾方法基于相位或者振幅调制,存在工作带宽窄或者分辨力低的问题。本文提出了一种宽带消色差的超表面滤波器,可以在不损失空间分辨力的情况下实现切趾成像。通过该滤波器在整个可见光波段完成了几乎无色散的相位调制。仿真结果表明,超表面滤波器的聚焦效率是相位滤波器的两倍;其成像对比度可以提升至高斯滤波器的三倍。通过我们的方法,在400 nm到700 nm的可见光波段内,点扩散函数的旁瓣能被压缩到10-5数量级,同时能够实现衍射极限甚至超衍射的分辨力。

       

      Abstract: Apodization has found many important applications in imaging and optical communication. Traditional apodization methods are based on the phase or amplitude modulation, suffering from either narrow working bandwidth, or reduced spatial resolution. Here, a broadband achromatic metasurface filter is proposed to realize apodization imaging without sacrificing the spatial resolution. With this filter, a nearly dispersionless phase modulation in the entire visible waveband can be achieved. The simulated results indicate that the focusing efficiency of the metasurface filter is twice larger than that of the phase filter and the imaging contrast can be improved by three times with the metasurface filter compared to the Gaussian filter. The sidelobes in the point spread function can also be efficiently suppressed to the scale of 10-5 in the whole visible spectrum ranging from 400 nm to 700 nm with our design. Additionally, the resolution of diffraction limit or even sub-diffraction can be achieved with this method.