Ling Xiulan, Chen Xin, Liu Xiaofeng
School of Information and Communication Engineering, North University of China, Taiyuan 030051, China.
Key Laboratory of Material Science and Technology for High Power Lasers, Shanghai Institute of Optics and Fine Mechanics, Shanghai 201800, China.
Micromachines (Basel). 2022 Jun 9;13(6):911. doi: 10.3390/mi13060911.
Based on a finite-difference time-domain method, we revisited the light field intensification in optical films due to defects with different geometries. It was found that defect can induce the local light intensification in optical films and the spherical defects resulted in the highest light intensification among the defect types investigated. Light intensification can increase with defect diameter and the relative refractive index between the defect and the film layer. The shallow defects tended to have the highest light intensification. Finally, the extinction coefficient of the defect had a significant effect on light intensification. Our investigations revealed that the light field intensification induced by a nano-defect is mainly attributed to the interference enhancement of incident light and diffracted or reflected light by defects when the size of the defect is in the subwavelength range.
基于时域有限差分法，我们重新研究了具有不同几何形状缺陷的光学薄膜中的光场增强现象。研究发现，缺陷能够在光学薄膜中引起局部光增强，并且在所研究的缺陷类型中，球形缺陷导致的光增强最高。光增强会随着缺陷直径以及缺陷与薄膜层之间的相对折射率的增加而增大。浅缺陷往往具有最高的光增强。最后，缺陷的消光系数对光增强有显著影响。我们的研究表明，当缺陷尺寸处于亚波长范围时，纳米缺陷引起的光场增强主要归因于缺陷对入射光与衍射光或反射光的干涉增强。
