Advanced Photonics, Vol. 2, Issue 3, 036002 (2020)
Liquid crystal integrated metalens with tunable chromatic aberration
Zhixiong Shen1,2, Shenghang Zhou1, Xinan Li1, Shijun Ge1,2, Peng Chen1,2, Wei Hu1,2,*, and Yanqing Lu1,*
- 1Nanjing University, College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, Collaborative Innovation Center of Advanced Microstructures, Nanjing, China
- 2Jiangsu Industrial Technology Research Institute, Institute for Smart Liquid Crystals, Changshu, China
Overcoming chromatic aberrations is a vital concern in imaging systems in order to facilitate full-color and hyperspectral imaging. By contrast, large dispersion holds opportunities for spectroscopy and tomography. Combining both functions into a single component will significantly enhance its versatility. A strategy is proposed to delicately integrate two lenses with a static resonant phase and a switchable geometric phase separately. The former is a metasurface lens with a linear phase dispersion. The latter is composed of liquid crystals (LCs) with space-variant orientations with a phase profile that is frequency independent. By this means, a broadband achromatic focusing from 0.9 to 1.4 THz is revealed. When a saturated bias is applied on LCs, the geometric phase modulation vanishes, leaving only the resonant phase of the metalens. Correspondingly, the device changes from achromatic to dispersive. Furthermore, a metadeflector with tunable dispersion is demonstrated to verify the universality of the proposed method. Our work may pave a way toward active metaoptics, promoting various imaging applications.
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