场控宽频消色差陶瓷基超构表面与器件研究

Metasurface devices are able to arbitrarily manipulate the amplitude, phase and polarization of light by artificially designing the periodic structure and the 2D arrangement of the sub-wavelength unit cells, however, the chromatic aberration (different phase accumulation through light propagation with various wavelengths and resonant phase dispersion) and narrow bandwidth response characteristics limit the application. In this proposal, we will develop the design theory of the Mie-resonance based ceramic broadband achromatic metasurface devices and study the tunability of mechanism controlled with external stimuli. Based on the Fermat principle and the Mie-resonance theory, we study the phase-frequency characteristics of the ceramic resonator, investigate its design and control method, and analyze the influence rules to the chromatic performance of the metasurface devices. The phase response of electric/magnetic dipoles of ceramic particles, the mechanism of the expansion to the phase control range due to the coupling of multipoles and the phase dispersion profile modulation laws are to be revealed. A single ceramic particles or the ceramic particle cluster are utilized to construct the phase shifter and realize the broadband achromatic metasurface devices. The response functions of the phase dispersion profile of the dielectric unit cells varying with the external fields and the eigen equation of the dynamic perfomance will be derived, and then the relationship between frequency band, performance and external fields can be built. This proposal offers a new design and fabrication method to construct actively controlled broadband achromatic metasurface devices with multi-frequency responses.

超构表面/器件通过亚波长二维周期排布的电磁基元可任意操纵电磁波的振幅、相位和极化模态，而由于固有色差（几何光学色差和电磁基元谐振色散）和窄频带响应限制了其实际应用。本课题拟研究一种宽频消色差Mie谐振陶瓷基超构表面与器件的设计构筑原理及其外场调控机制。由几何光学的费马原理和Mie散射原理出发，研究陶瓷介质颗粒谐振基元的相位－频率依赖关系、设计调控方法以及对超构表面/器件消色差性能的影响规律；揭示陶瓷介质颗粒的电磁偶极谐振及多级高阶谐振间耦合的相位响应频段拓宽的物理本质以及其对相位色散曲线的调制规律；利用单个或多个陶瓷介质颗粒团簇构造相位控制基元以实现宽频消色差超构表面/器件的构筑；阐明介质基元相位色散曲线的外场响应函数，推演器件性能动态变化的本征方程，建立工作频段、器件性能与外场动态调制间的关联。该研究为响应频段和性能可主动调控消色差超构表面/器件的构筑提供了一种新的理论方法和实现途径。

超构表面/器件通过亚波长二维周期排布的电磁基元可任意操纵电磁波的振幅、相位和极化模态，而由于固有色差（几何光学色差和电磁基元谐振色散）和窄频带响应限制了其实际应用。本课题拟研究一种宽频消色差Mie谐振陶瓷基超构表面与器件的设计构筑原理及其外场调控机制。所取得的成果如下：（Ⅰ）探索了构筑宽频消色差超透镜的原理，基于几何相位的调制方法实现透镜聚焦的相位分布，采用介质谐振单元与介质层复合的设计实现了更大范围相位调节，进而实现聚焦功能，采用高折射率介质设计了全介质超透镜器件；（Ⅱ）揭示了介质基宽频超构表面的各向异性电磁参数实现的物理本质，实现了不同方向上电磁参数分量的解耦，并给出了温度场调控各向异性谐振系统的调谐机制；（Ⅲ）基于去耦合离散点偶极子理论对介质颗粒基元的电磁谐振进行多极分解，证明了高阶偶极谐振能够有效消除相邻电和磁偶极矩间的频谱耦合，可用于实现电/镜超构表面的切换，选择性地抑制不同电磁多极矩激发理想的纯环形偶极响应；（Ⅳ）开发了一套先进且完善的陶瓷微纳加工工艺，制备了高介电常数介质颗粒，发展了超构表面器件的设计与制备方法，并对器件进行外场调控性能验证；（Ⅴ）开展了基于其他新原理的超构表面应用器件探索研究。