报告摘要：

    Metasurfaces have transformed wavefront engineering by enabling subwavelength control over amplitude, phase, and polarization through tailored nanostructuring. High-quality-factor platforms now allow efficient two-dimensional wavefront manipulation, while engineered spatial dispersion and nonlocality have expanded metasurface functionality toward optical signal processing and analog computing. Despite these advances, even when dynamic mechanisms are introduced (via electro-optic modulation, carrier injection, or optical pumping), the achievable reconfigurability typically constitutes a modulation of a pre-designed response. In parallel, nonlinear flat optics has emerged as a powerful route to overcome the limitations of linear transfer functions. By combining nonlinearity with engineered nonlocality, flat optical platforms can synthesize higher-order Volterra kernels and nonlinear image-processing operations beyond conventional Fourier optics. It has been shown that even homogeneous nonlinear films can perform broadband edge detection and nonlinear spatial filtering without relying on resonances, and that polarization-sensitive nonlinear responses enable compact polarimetric imaging architectures . Furthermore, nonlinear wave mixing enables programmable infrared-to-visible upconversion imaging with dynamically tunable focusing, as well as nonlinear angular-momentum addition and structured-light control in isotropic flat platforms.
    Here, we introduce the concept of reconfigurable virtual metasurfaces based on nonlinear wave mixing in flat optics. We show that spatially structured optical fields can program an effective nonlinear polarization landscape that reproduces and extends metasurface functionalities, enabling dynamically tunable wavefront control and nonlinear image processing within a unified framework. This approach establishes a software-defined layer that can complement conventional metasurface s, extending their functionality beyond the constraints of linear optics and fabrication-defined design.

报告人简介：

    Costantino De Angelis，教授，现任意大利布雷西亚大学副校长，负责协调布雷西亚大学博士生院相关工作，布雷西亚大学电磁场领域正教授，并担任电磁场与光子学研究团队负责人。他长期从事非线性光学、纳米光子学、周期性光子结构、超表面及光子器件等方向研究，在离散与周期性非线性光子结构、纳米天线及非线性纳米光子器件设计等领域具有重要国际影响。De Angelis教授曾受邀在麻省理工学院、澳大利亚国立大学、巴黎第七大学、ITMO 大学等国际知名机构担任访问教授，主持多项欧盟、NATO、意大利国家级及国际合作项目。其研究成果包括多项专利、250余篇国际期刊论文和200余篇国际会议论文报告，Google Scholar引用超过10000次，h指数52。De Angelis教授因其在离散与周期性非线性光子结构、纳米天线及非线性纳米光子器件设计方面的重要贡献，于2017年当选为OPTICA Fellow。