Jin Qijian, Liang Gaofeng, Kong Weijie, Liu Ling, Wen Zhongquan, Zhou Yi, Wang Changtao, Chen Gang, Luo Xiangang
Key Laboratory of Optoelectronic Technology & Systems (Chongqing University), Ministry of Education, and College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, China.
State Key Lab of Optical Technologies on Nano-fabrication and Micro-engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China.
Nanophotonics. 2022 Mar 15;11(8):1643-1651. doi: 10.1515/nanoph-2022-0013. eCollection 2022 Mar.
A negative index metamaterial (NIM) at ultraviolet range is constructed with stacked plasmonic waveguides. Based on the waveguides performing antisymmetric modes, the negative refractions of both wavevector and energy flow are realized when a TM-polarized light with a wavelength of 365 nm incidents on the plane of the layers. It is proved that the NIM could be introduced into subwavelength photolithography for extending working distance. Both theoretical and experimental results indicate that the patterns with a feature size of 160 nm can be reproduced in photoresist with a 100 nm-thick air working distance. Moreover, arbitrary two-dimensional patterns with a depth reach 160 nm can be obtained without diffraction fringe by employing a nonpolarized light. This design gives new insights into the manipulation of light. The improved working distance, well-shaped patterns over large area present an innovative method for improving subwavelength photolithography.
一种用于紫外波段的负折射率超材料（NIM）由堆叠的等离子体波导构成。基于波导中传播的反对称模式，当波长为365 nm的TM偏振光入射到层平面时，实现了波矢和能流的负折射。证明了该负折射率超材料可引入亚波长光刻以延长工作距离。理论和实验结果均表明，在光刻胶中可再现特征尺寸为160 nm且空气工作距离为100 nm厚的图案。此外，通过使用非偏振光可获得深度达160 nm的任意二维图案且无衍射条纹。该设计为光的操控提供了新的见解。改进的工作距离、大面积形状良好的图案为改进亚波长光刻提供了一种创新方法。
