摘要
提出了一种利用不同大小的高折射率介质方柱组成的梯度光子晶体来实现聚焦的方法。数值仿真计算证明,该聚焦器件能实现高能量利用率和接近衍射极限的聚焦光斑。在透镜两侧涂上一层增透膜,可以有效地抑制旁瓣和提高能量利用率。随着透镜填充因子的增大,焦点的能量随之增强。针对波长10.6μm,设计了一个口径为100μm,焦距为50μm的梯度光子晶体结构透镜,利用时域有限差分方法得出透镜能量利用率在填充因子为44.7%时达到了48.5%,焦斑大小也接近衍射极限。
A graded photonic crystal formed by the varying the high-refractive-index square dielectric rods is used as a structured lens to focus.This lens can realize high energy utilitzation and large numerical aperture.Otherwise,the energy utilization and the imaging quality can be greatly improved by adding thin dielectric films on the two sides of the lens,and the energy utilization increases as the fill factor increases.A lens with an aperture of 100 μm and a focal length of 50 μm is designed for the wavelength of 10.6 μm.The energy utilization reaches 48.5% in the case of filling factor as 44.7% by finite difference and time domain（FDTD）algorithm,and the spot size approaches to the diffraction limit.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2010年第8期2427-2431,共5页
Acta Optica Sinica
基金
国家973计划(2006CB302900)
中国科学院功能晶体与激光技术重点实验室开放课题资助课题
关键词
光学器件
能量效率
时域有限差分
梯度光子晶体
薄膜
填充因子
optical devices
energy utilization
finite difference and time domain
graded photonic crystal
thin films
filling factor
