超表面透镜的宽带消色差成像（特邀）

超透镜是一种由二维亚波长阵列结构表面所设计的透镜，其对光场中振幅、相位和偏振的调控能力较灵活，同时具有低损耗、易集成、超轻薄等优点，近些年引起了科研人员广泛的研究兴趣。然而在大多数情况下，针对特定波长设计的超透镜会遭受较大的色差，从而限制了其在多波长或宽带应用中的成像作用。超透镜因其二维平面结构引入了新的自由度，在对色差的消除上体现了新的潜力。文中报道了多种不同的消色差超透镜设计及其消色差调控机理，并对现有的消色差超透镜从调制波段类型进行了分类，如对离散波长的和对连续波长的消色差超表面透镜，后者又可从工作模式上分类为透射型和反射型，最后介绍了超透镜阵列在成像上的应用以及其在大景深宽带消色差器件上的前景。

Broadband achromatic imaging with metalens (Invited)

Metalens, the specific type of lens designed with the surfaces mading of two dimensional array at the subwavelength scale, has shown great flexibilities to control the light field, including the arbitrary modulation abilities of amplitude, phase and polarization at the subwavelength scale. Moreover, the metalens possesses the unique advantages of low loss, integratable and conformable design and ultrathin, therefore attracts immense attentions in recent years. However, in most cases, the metalens designed for a specific wavelength may penetrate through the large chromatic aberration, which limits their usefulness in multi-wavelength or broadband applications. On the other hand, the metalens has renewed new degrees of freedom due to its two-dimensional planar structure, which has the potential in the elimination of chromatic aberration. Some different typical achromatic metalens designs and their achromatic modulation mechanism were reviewed, the existing achromatic metalens were classified from the types of modulated light bands, such as the achromatic matelens for discrete and continuous wavelength respectively, and the latter can be classified as transmissive and reflective from the working mode. Finally, the application of metalenses array in imaging and their prospect of broadband achromatic devices of large depth of field were introduced.