亚波长尺度下混合等离子泄漏模式激光
Hybrid plasmonic leaky-mode lasing on subwavelength scale
摘要
Abstract
Due to the existence of diffraction limit as the basic characteristic of light, the lasing on sub-wavelength scale cannot be achieved by traditional methods. In order to break this diffraction limit, a stacked structure composed of metal, dielectric layer and semiconductor was designed in this paper to achieve lasing on the deep subwavelength scale and its influence on the propagation mode was discussed. In terms of struc-tural design, we used silver, a metal with low dielectric constant, as the substrate, a 10 nm-thick LiF layer as the dielectric layer, and a ZnO semiconductor nanowire with hexagonal section as the high-dielectric-con-stant layer. We adopted the finite-difference eigen mode and Finite-Difference Time-Domain (FDTD) meth-od to perform optical simulation of the designed structure. First, by changing the nanowire diameter and us-ing the finite eigen mode, the optical modes in the dielectric layer were analyzed to obtain four mode distri-butions. Then the effective refractive indexes and losses of the four optical modes at different nanowire dia-meters were used to calculate the corresponding waveguide propagation distances and lasing threshold gains. Finally, the three-dimensional FDTD method was introduced to simulate the electric field distribution of the four modes during the steady-state laser emissionin of the nanowire. The results showed that there were hy-brid plasmonic mode and hybrid electric mode in the dielectric layer between the nanowire and the metal sub-strate. When the diameter of ZnO nanowire was smaller than 75 nm, there was no effective physical optical mode, that is, both the hybrid plasmonic mode and the hybrid electric mode were cut off. When the nanowire diameter was larger than 75 nm, the hybrid plasmonic mode could effectively exist. The hybrid electric mode did not appear until the nanowire diameter reached 120 nm. Although the hybrid plasmonic mode could be better confined to the dielectric layer, its loss was too large and its propagation distance was relatively small. In addition, the hybrid electric mode traveled a longer distance than hybrid plasmonic mode. At the given dia- meter of the micron wire (D = 240 μm), the hybrid electric mode propagated for over 50 μm. In conclusion, the hybrid leaky mode on the deep subwavelength scale can break the optical diffraction limit and realize lasing.关键词
激光/泄漏模式/亚波长/波导Key words
laser/leaky-mode/subwavelength/waveguide分类
数理科学引用本文复制引用
严闪闪,王双鹏,宿世臣..亚波长尺度下混合等离子泄漏模式激光[J].中国光学,2021,14(2):397-408,12.基金项目
国家自然科学基金(No. 61574063) （No. 61574063）
广东省科技基金(No. 2017A050506047,No. 2017B030311013) （No. 2017A050506047,No. 2017B030311013）
广州市科技计划(No. 2016201604030047,No. 201804010169) （No. 2016201604030047,No. 201804010169）
广东省科技计划(No. 2019B090905005) （No. 2019B090905005）
澳门特别行政区科学技术发展基金(No. 0125/2018/A3,No. 0071/2019/AMJ) （No. 0125/2018/A3,No. 0071/2019/AMJ）
澳门大学MYRG(No. MYRG-00149-FST)Supported by National Natural Science Foundation of China (No. 61574063) （No. MYRG-00149-FST）
Science and Technology Pro-gram of Guangdong Province (No. 2017A050506047, No. 2017B030311013) （No. 2017A050506047, No. 2017B030311013）
Guangzhou Science and Techno-logy Project (No. 2016201604030047, No. 201804010169) （No. 2016201604030047, No. 201804010169）
Guangdong Province Scientific and Technology Project (No. 2019B090905005) （No. 2019B090905005）
Science and Technology Development Fund (No. 0125/2018/A3, No.0071/2019/AMJ) from Macau SAR （No. 0125/2018/A3, No.0071/2019/AMJ）
Multi-Year Research Grants (No. MYRG-00149-FST) from University of Macau （No. MYRG-00149-FST）
