Zheng Ze, Sanderson Gabriel, Sotoodeh Soheil, Clifton Chris, Ying Cuifeng, Rahmani Mohsen, Xu Lei
Advanced Optics and Photonics Laboratory, Department of Engineering, School of Science & Technology, Nottingham Trent University, Nottingham NG11 8NS, UK.
Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK.
Engineering (Beijing). 2025 Jun;49:90-95. doi: 10.1016/j.eng.2025.04.023.
Nonlinear wavefront shaping is crucial for advancing optical technologies, enabling applications in optical computation, information processing, and imaging. However, a significant challenge is that once a metasurface is fabricated, the nonlinear wavefront it generates is fixed, offering little flexibility. This limitation often necessitates the fabrication of different metasurfaces for different wavefronts, which is both time-consuming and inefficient. To address this, we combine evolutionary algorithms with spatial light modulators (SLMs) to dynamically control wavefronts using a single metasurface, reducing the need for multiple fabrications and enabling the generation of arbitrary nonlinear wavefront patterns without requiring complicated optical alignment. We demonstrate this approach by introducing a genetic algorithm (GA) to manipulate visible wavefronts converted from near-infrared light via third-harmonic generation (THG) in a silicon metasurface. The Si metasurface supports multipolar Mie resonances that strongly enhance light-matter interactions, thereby significantly boosting THG emission at resonant positions. Additionally, the cubic relationship between THG emission and the infrared input reduces noise in the diffractive patterns produced by the SLM. This allows for precise experimental engineering of the nonlinear emission patterns with fewer alignment constraints. Our approach paves the way for self-optimized nonlinear wavefront shaping, advancing optical computation and information processing techniques.
非线性波前整形对于推进光学技术至关重要，可实现光学计算、信息处理和成像等应用。然而，一个重大挑战是，一旦超表面制造完成，其产生的非线性波前就固定了，灵活性很小。这种限制通常需要为不同的波前制造不同的超表面，既耗时又低效。为了解决这个问题，我们将进化算法与空间光调制器（SLM）相结合，使用单个超表面动态控制波前，减少了对多种制造的需求，并能够在无需复杂光学对准的情况下生成任意非线性波前图案。我们通过引入遗传算法（GA）来操纵硅超表面中通过三次谐波产生（THG）从近红外光转换而来的可见波前来演示这种方法。硅超表面支持多极米氏共振，可强烈增强光与物质的相互作用，从而在共振位置显著提高THG发射。此外，THG发射与红外输入之间的立方关系降低了SLM产生的衍射图案中的噪声。这使得在较少对准约束的情况下对非线性发射图案进行精确的实验设计成为可能。我们的方法为自优化非线性波前整形铺平了道路，推动了光学计算和信息处理技术的发展。
