动态可调谐的非线性超构材料及其应用的研究

Nonlinear metamaterials has been one of today’s hottest research subjects in the field of nano-photonics. In this project, we mainly focus on several new scientific problems emerging in the field of nonlinear metamaterials. We plan to study the polarization of the harmonic generation from the constituents, and design the nonlinear micro/nano optical devices that can generate the arbitrary polarization states with the aid of the phase gradient in the metamaterials. We will develop new methods for nonlinear metamaterials based holograms, and construct wavelength, polarization and spin multiplexed nonlinear metasurface holography. We will study the effect of the deformation induced shape change of the constituents and period change of the metamaterials on the wavefront and polarization of the harmonic wave, and construct flexible substrate based nonlinear metamaterials with dynamically tunable functions such as harmonic wave splitting, harmonic wave deflection, and focusing. We will also develop new mechanisms that can be exploited to dynamically tune the optical properties of the nonlinear metamaterials. By introducing the dielectrics with optical properties that are capable of being tuned under external electric fields or optical fields into metamaterials, we will design the nonlinear metamaterials and nonlinear micro/nano devices which allow real-time manipulations of the wave front and polarization of the harmonic waves. Furthermore, we will try to use the proposed dynamically tunable nonlinear metamaterials to realize the nonlinear holographic optical devices that can provide dynamic holographic images. We hope the implementation of this project can provide reliable scientific basis and technical support for the future application researches.

非线性超构材料是当今纳米光子学的研究热点，本项目围绕其中的一些新的科学问题，主要研究超构材料中结构单元的谐波偏振调控特性，结合超构材料中的相位梯度，设计能产生任意偏振态的非线性微纳光子器件；发展基于非线性超构材料的全息成像的新原理、新方法，构建具有波长、偏振以及自旋复用功能的非线性全息光学器件；研究柔性衬底形变导致的结构单元的形状改变以及超构材料周期变化对谐波波前和谐波偏振的影响，构建基于柔性衬底的具有对谐波分束、光束偏转、聚焦等动态调控功能的非线性超构材料；发展非线性超构材料高速动态调控的新原理、新方法，结合光学性质受外电场或光场调控的介电材料，实现谐波波前、谐波偏振可实时调控的非线性超构材料和非线性微纳光子器件，并探索其在全息图像动态可调的非线性全息光学器件上的应用，为后续应用研究提供可靠的科学依据和技术支撑。

超表面器件因其可以对光波相位在亚波长尺度下进行有效操控，在线性和非线性光学领域有重要的应用前景，因而受到国内外的极大关注。我们在本项目中主要研究了非线性超构材料中谐波的产生、动态调控及其应用，取得的主要研究成果及其科学意义包括：1）基于介质加载的方法，设计了新型介质-金属等离激元超表面，实现了局域电场热点从金属到介质表面的转移，并获得了更大的局域电场强度，为进一步提高非线性谐波信号强度提供了一种新途径；2）揭示了金属开口谐振环和旋转90度的开口谐振环互补结构在相同线偏振基波激励下，所产生的二次谐波具有正交的线偏振态，并基于此设计制备了集合非线性谐波产生、分束和偏振的任意调控为一体的非线性超构表面；3)发展了导波驱动非线性超表面中位相调控方法，结合相变材料实现了两种相态下分别针对基波和二次谐波的聚焦，为超表面的线性及非线性多功能复合调控提供了一种新的可能途径；4) 结合人工带隙光学微结构设计理论，设计并实现了二维高阶光子拓扑绝缘体，为实现具有拓扑保护的光学局域态及其调控提供了新的研究思路，也为后续拓扑非线性光学的研究提供可靠的科学依据和技术支撑。