Visible light focusing flat lenses based on hybrid dielectric-metal metasurface reflector-arrays.
Visible light focusing flat lenses based on hybrid dielectric-metal metasurface reflector-arrays.
复制标题
基于混合介电金属超表面反射器阵列的可见光聚焦平面透镜
DOI：
10.1038/srep45044
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发表时间：
2017-03-23
影响因子：
4.6
通讯作者：
Xu T
中科院分区：
文献类型：
--
作者：
Fan Q;Huo P;Wang D;Liang Y;Yan F;Xu T
传统的基于金属谐振纳米天线的超表面反射器阵列用于控制光的波前聚焦，在光学频率处存在较大的欧姆损耗。在这里，我们克服了这一挑战，构建了一种非谐振，混合介电-金属结构，由TiO2纳米片与Ag反射器衬底相结合，在可见光范围内提供宽带响应和高偏振转换效率。基于这种结构的反射平面透镜具有优异的聚焦性能，光斑尺寸接近衍射极限。此外，通过采用叠加相位分布设计来控制反射光的波前，证明了平面透镜的多种功能，如多焦和消色差聚焦。这种反射平面透镜将在可见光成像和传感系统中找到各种应用。
Conventional metasurface reflector-arrays based on metallic resonant nanoantenna to control the wavefront of light for focusing always suffer from strong ohmic loss at optical frequencies. Here, we overcome this challenge by constructing a non-resonant, hybrid dielectric-metal configuration consisting of TiO2 nanofins associated with an Ag reflector substrate that provides a broadband response and high polarization conversion efficiency in the visible range. A reflective flat lens based on this configuration shows an excellent focusing performance with the spot size close to the diffraction limit. Furthermore, by employing the superimposed phase distribution design to manipulate the wavefront of the reflected light, various functionalities, such as multifocal and achromatic focusing, are demonstrated for the flat lenses. Such a reflective flat lens will find various applications in visible light imaging and sensing systems.