Wang Guangqing, Liang Yubo, Leng Jin, He Xiaoyong, Lin Fangting, Liu Feng
Appl Opt. 2022 Jul 20;61(21):6152-6157. doi: 10.1364/AO.458551.
Based on the proposed elliptical dielectric fiber-polyethylene gap-3D Dirac semimetal (DSM) hybrid plasmonic waveguide structure, the tunable propagation characteristics have been systematically investigated in the terahertz region, taking into account the influences of the structural parameters, the modified dielectric fiber, and the 3D DSM Fermi levels. The results show that as the ratio of the elliptical semi-axis along the -direction and the -direction (/) increases, the hybrid mode confinement increases. The real part of the effective mode index and propagation length increase with increasing the refractive index of the elliptical fiber. The propagation length and figure of merit of the hybrid modes reach 1.56×10µ and 300, respectively. In addition, by changing the Fermi level of the 3D DSM layer, the propagation properties of the hybrid modes can also be modulated in a wide range, e.g., the modulation depth of the propagation length reaches about 71.53% if the Fermi level varies in the range of 0.03-0.15 eV. The propagation properties of the hybrid modes are enhanced significantly by utilizing the modified three elliptical fiber structures, the real part of the effective mode index, and the propagation length of the modified structure are enhanced simultaneously. The results are very helpful for understanding the tunable mechanism of the 3D DSM devices and aids the design of novel plasmonic devices, e.g., lasers, modulators, and resonators.
基于所提出的椭圆介质光纤-聚乙烯间隙-三维狄拉克半金属（DSM）混合等离子体波导结构，考虑到结构参数、改性介质光纤和三维DSM费米能级的影响，系统研究了太赫兹区域内的可调传播特性。结果表明，随着沿x方向和y方向的椭圆半轴之比（/）增加，混合模式限制增强。有效模式折射率的实部和传播长度随着椭圆光纤折射率的增加而增加。混合模式的传播长度和品质因数分别达到1.56×10µ和300。此外，通过改变三维DSM层的费米能级，混合模式的传播特性也可以在很宽的范围内进行调制，例如，如果费米能级在0.03-0.15 eV范围内变化，传播长度的调制深度达到约71.53%。利用改性的三椭圆光纤结构显著增强了混合模式的传播特性，同时有效模式折射率的实部和改性结构的传播长度也得到了增强。这些结果对于理解三维DSM器件的可调机制非常有帮助，并有助于新型等离子体器件（如激光器、调制器和谐振器）的设计。
