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• Photonics Research
• Vol. 9, Issue 7, 07001384 (2021)
Hanmeng Li1、2、†, Xingjian Xiao1、2、†, Bin Fang1、2, Shenglun Gao1、2, Zhizhang Wang1、2, Chen Chen1、2, Yunwei Zhao1、2, Shining Zhu1、2, and Tao Li1、2、*
Author Affiliations
• 1National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China
• 2Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
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Abstract

The design of large-scale, high-numerical-aperture, and broadband achromatism is a big challenge in metalens research. In fact, many colorful imaging systems have RGB color filters, which means the achromatism only for RGB lights would be sufficient. Avoiding broadband achromatism is expected to greatly improve the working efficiency of metalenses. Nevertheless, a proper bandpass filter is necessary under a white light illumination in the metalens integrated imaging system. Here we propose a bandpass-filter-integrated multiwavelength achromatic metalens ($NA=0.2$), which is designed using a searching optimization algorithm to achieve the achromatism of RGB lights with high efficiencies. The bandpass filter is implemented by composite DBRs and defect layers, by which three desired wavelengths are selected out. The simulations and experiments on the filter-integrated metalens definitely show a good RGB achromatism. Further imaging experiments demonstrate a higher signal-to-noise ratio and resolution compared with the one without the filter. Our approach provides not only an RGB achromatic meta-imaging device but also a new route to access a highly efficient spectrum tailoring metasystem by incorporating bandpass filter designs.

1. INTRODUCTION

Metasurfaces with flexible control of the amplitude, phase, and polarization of light by subwavelength nanostructures have been introduced and widely developed [14]. Based on the potential to control and manipulate the flow of light, a large number of metasurfaces have been proposed recently as alternatives to conventional optical elements, promoting the miniaturization and function expansion of the device. In addition to various potential applications of metasurfaces, such as holograms [5,6], wave plates [7,8], beam shapers [9,10], and optical switches [11,12], metalenses have attracted intense interest in the last few years due to their wide applications in both consumer and industry products [1316]. Great efforts have been made toward improving the performance of the metalens, especially the chromatic aberration correction [1728].

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Hanmeng Li, Xingjian Xiao, Bin Fang, Shenglun Gao, Zhizhang Wang, Chen Chen, Yunwei Zhao, Shining Zhu, Tao Li. Bandpass-filter-integrated multiwavelength achromatic metalens[J]. Photonics Research, 2021, 9(7): 07001384