二元亚波长衍射微透镜的设计
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