原子层厚度菲涅尔波带片及其宽谱聚焦特性

Atomically thin Fresnel zone plate with broadband focusing property

基于菲涅尔波带片构型的平面衍射透镜在现代光学系统中发挥着重要的作用,是高端光学成像系统等应用的关键元器件之一。现有菲涅尔波带片结构多基于金属薄膜或高折射率电介质材料来制备,难以满足集成光电子系统可集成化的核心需求。本文提出一种基于原子层厚度二维材料的菲涅尔波带片结构,基于损耗辅助的相位调控机制,在原子层厚度的MoS_(2)二维半导体材料上实现了对整个可见光波段显著的相位调制能力。利用飞秒激光加工技术,制备了二元相位型菲涅尔波带片,理论和实验验证了宽谱衍射受限的聚焦特性。与单层过渡金属硫化物材料的直接带隙特性相结合,该工作为实现光子集成系统提供了一种可行的路径。

The planar diffractive lens in zone plate-type configuration plays important roles in the modern optical system,especially in the advanced optical imaging system.Most of them are constructed with opaque metal or dielectric materials with a high refractive index,which restricts the integration possibility for the miniaturized photonic systems.In this work,we proposed and experimentally demonstrated an atomic thin Fresnel zone plate device with 2D semiconductor material.Based on the loss-assisted phase modulation mechanism,an extraordinary phase modulation capability in the entire visible region has been achieved by an atomic thin MoS_(2)sheet.By utilizing the femtosecond laser scribing technique,a binary phase Fresnel zone plate has been fabricated on the atomic thin MoS_(2)sheet.The diffraction-limited focusing property in broadband has been demonstrated in simulation and experiments.Combining with the direct bandgap property of the monolayer MoS_(2)material,this phenomenon may pave the road for the integrated optical system.