二元亚波长衍射微透镜的设计
时间:2018-11-10 16:03 来源:毕业论文 作者:毕业论文 点击:次
| 摘要衍射透镜是典型的、应用广泛的衍射光学元件，在波前整形、波前传感、光通信、光扫描及光聚能器等多项功能上发挥了重要作用。近年来，随着计算机技术和微电子工艺的飞速发展，使二元亚波长衍射微透镜的制作成为可能，并可克服采用微电子工艺制作多台阶微透镜时存在的制作难题，以及采用激光直写技术制作连续浮雕结构微透镜时由于工艺不成熟带来的轮廓变形问题。 本文设计了连续浮雕衍射微透镜和与其等效的二元亚波长衍射微透镜， 采用旋转体时域有限差分法对通过计算机辅助设计出的元件进行了严格的矢量分析， 给出了各元件在焦平面的场强分布。分析结果表明,本文设计的二元亚波长微透镜对连续浮雕微透镜有很好的等效效果；填充因子的脉冲宽度调制法要优于填充因子的线性近似法；制作相对误差不大时深度误差和宽度误差对微透镜聚光能力的影响不大。 30096 毕业论文关键词 亚波长；衍射；微透镜；旋转体时域有限差分法 Title Design of Binary Subwavelength Diffractive Microlens Abstract The diffraction lens is typical, wide application of diffractive optical elements, in a number of wave front shaping, wavefront sensing, optical communication, optical scanning and light gathering is play an important role. In recent years, with the rapid development of computer technology and microelectronics technology, binary subwavelength diffractive micro lens made it possible, and can overcome the microelectronics manufacture technics of multilevel microlens with existing problems in making and using laser direct writing technology making continuous embossed microlens structure due to immature technology brings the contour deformation. The design procedure of subwavelength diffractive microlenses was presented based on the combination of scalar diffractive theory and effective medium theory.As examples continuous-relief microlenses and their counterparts of binary subwavelength diffractive microlenses were designed with computer code. Pulse-width-modulated approximation and linear approximation were employed to determine the width of subwavelength features.Body-of-revolutionary finite-difference time-domain method was used for the analysis of the designed microlenses to test whether the binary subwavelength profile can achieve effects similar to continuous-relief profile and effect of fabrication error on microlens ability of focusing optical energy. The electric field distributions on the focal planes of designed microlenses were illustrated.The numerical results showed that the designed binary subwavelength microlenses have nearly equal ability of ocusing optical energy with the continuous-relief microlenses they simulated,the pulse-width-modulated approximation method has better efficiency than the linear approximation method,and the fabrication depth error and width error have little effect on microlens efficiency of focusing optical energy when the relative error is small. Keywords Subwavelength;Diffractive;Microlens;Finite-difference time-domain method 目次 1引言1 1.1二元光学及其内涵1 1.2衍射微光学器件设计理论的研究进展1 1.2.1基于标量衍射理论的设计方法1 1.2.2基于矢量衍射理论的设计方法2 1.2.3衍射微光学器件设计理论的发展趋势3 1.3衍射微光学器件制作方法的研究进展3 1.3.1传统套刻法3 1.3.2激光直写法4 2基于标量衍射理论的精细化设计.5 2.1输入平面光场振幅的频谱5 2.2衍射光学器件复振幅透过率的频谱5 3亚波长结构及等效介质理论.8 3.1亚波长结构8 3.2一文亚波长结构的等效介质理论——零级等效近似8 (责任编辑：qin) |