太赫兹大视场宽带消色差超构透镜

Large Field of View Broadband Achromatic Metalens in Terahertz Regime

基于超构透镜的太赫兹成像系统因紧凑的体积受到广泛关注。现有太赫兹超构透镜仅能实现消色差或大视场成像,需要大视场宽带消色差超构透镜来进一步提升太赫兹系统的成像质量。文中介绍了一种工作在0.3~0.5THz,数值孔径0.707,直径10mm,视场100°的太赫兹大视场消色差硅基超构透镜。该超构透镜采用了二次非球面型相位剖面,减小了轴外像差,实现了大视场;选取了相位和色散满足要求的单元进行布阵,消除了色差。因此,它有望被广泛应用在生物检测、太赫兹成像等领域。

Terahertz imaging systems based on metalenses have attracted widespread attention due to their compact size.At present,terahertz metalens can only achieve achromatic or large-field imaging,so a large-field broadband achromatic metalens is needed to further improve the imaging quality of terahertz systems.In this article,a large field of view and broadband achromatic silicon based metalens was introduced,which operates in the terahertz region with a numerical aperture of 0.707,a diameter of 10mm,and a field of view of 100°.The metalens uses a quadratic aspheric phase profile to reduce off-axis aberrations,and selects units with phase and dispersion that meet the requirements for arranging the array to eliminate chromatic aberration.This metalens is expected to be used in areas such as biological detection and terahertz imaging.