Acta Photonica Sinica, Volume. 54, Issue 3, 0323002(2025)

Vari-focal Super-resolution Graphene Oxide Metalens Based on Wavelength Modulation

Yongchang DING1, Xueyan LI1、*, Yijian WU2、**, Lieshan ZHANG1, and Di CHANG1
Author Affiliations
  • 1Precision Measurement Laboratory,School of Information Science and Engineering,Zhejiang Sci-Tech University,Hangzhou 310018,China
  • 2School of Computer Science and Artificial Intelligence,Wenzhou University,Wenzhou 325000,China
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    The large size of traditional optical lenses limits their application in compact image sensors. In recent years, graphene oxide metalens have promoted the development of optical lenses toward miniaturization and integration. Since the inherent diffraction properties of graphene oxide metalens lead to the phenomenon of chromatic aberration, optical zoom based on wavelength modulation can be realized by using chromatic aberration as a new dimension, which can achieve the effect of continuous repeatable zoom without moving the optical components and only by changing the wavelength of the incident light.In this paper, a wavelength-modulated axial zoom super-resolution graphene oxide metalens system design method based on a genetic algorithm is proposed. By utilizing the phase-amplitude dependence of graphene oxide and reduced graphene oxide materials, phase and amplitude are simultaneously modulated to achieve super-resolution focusing based on incident light wavelength modulation. In the operating wavelength range of 432~632 nm, the objective function is set to the incident light of different wavelengths has the maximum optical field intensity at the preset focal length, and the wavelength-modulated optical zoom can be realized by using this objective function. During the optimization design process, the radius of the graphene oxide metalens is fixed at 150 μm, and the numerical aperture can be increased by decreasing the focal length, which in turn improves the imaging resolution, so the optimization constraints of the minimum numerical aperture requirement are introduced, and by setting the minimum numerical aperture to 0.4, the super-resolution focusing can be achieved in the operating wavelength range of 432~632 nm. Genetic algorithms were then used to inverse design the ring structure parameters of the graphene oxide metalens based on the predefined objectives and optimization constraints. During the optimization process of the genetic algorithm, selection, crossover and mutation are continuously performed, and the algorithm will stop iterating when the convergence condition that the distribution of the radius of the reduced graphene oxide ring has not changed for 50 consecutive generations is satisfied. The final output is the optimal solution of the evolved population, that is, the best ring radius distribution, which not only meets the design requirements but also has stability and reliability. By utilizing the proposed genetic algorithm inverse design theory, we designed compliant zoom super-resolution graphene oxide metalens with a maximum ring radius of 150 μm, a total of 67 reduced graphene oxide rings, a graphene oxide film thickness of 200 nm, a reduced graphene oxide film thickness of 100 nm, a width of 0.8 μm for each ring, and a center distance of at least 0.9 μm between two neighboring rings to ensure that graphene oxide and reduced graphene oxide regions are distributed alternately. The simulation results show that the designed radial resolution of the zoom super-resolution graphene oxide metalens exceeds the diffraction limit of over the working wavelength range, while the focal length is adjustable with the working wavelength in the range of 201.6~318.8 μm, and the zoom range reaches 117.2 μm, and the simulation results are in favorable consistency with the theoretically pre-determined results. The maximum focusing efficiency is 82.07% and the average focusing efficiency is 57.53% over the whole working wavelength range, with favorable focusing spot uniformity, high focusing intensity and favorable consistency in the bandwidth from 442 nm to 592 nm. The designed zoom super-resolution graphene oxide metalens achieves fast, continuous, repeatable zooming and super-resolution focusing effects through precise modulation of the phase and amplitude of the incident light, which can be further applied to the study of micro-and nano-optics, and provides a new way for miniaturized, integrated, and non-mechanically movable optical zoom systems.

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    Yongchang DING, Xueyan LI, Yijian WU, Lieshan ZHANG, Di CHANG. Vari-focal Super-resolution Graphene Oxide Metalens Based on Wavelength Modulation[J]. Acta Photonica Sinica, 2025, 54(3): 0323002

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    Paper Information

    Category: Optical Device

    Received: Aug. 12, 2024

    Accepted: Oct. 12, 2024

    Published Online: Apr. 22, 2025

    The Author Email: Xueyan LI (xueyanli8023@zstu.edu.cn), Yijian WU (20180188@wzu.edu.cn)

    DOI:10.3788/gzxb20255403.0323002

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