Diffractive micro-optical elements for implementing hollow beam and bi-focus simultaneously

作者：Liu Juan^*; Zhang Guo ting; Sun Fang; Hu Chuan fei; Liu Yun

来源：Optics and Laser Technology, 2008, 40(7): 912-919.

DOI：10.1016/j.optlastec.2008.01.019

• diffractive micro-optical element
• sub-wavelength feature size
• boundary element method

We design diffractive micro-optical elements (DMOEs) with sub-wavelength characteristic size based on a half-R-phase shifting scheme, with the aim of realizing a hollow beam and bi-focus simultaneously. The optical properties of DMOEs, such as the positions of the real focal planes, the aspect ratio of the hollow beam and the diffraction efficiency, are investigated by using the rigorous electromagnetic theory and the boundary element method. The numerical results show that a well-defined hollow beam and bi-focus are achieved simultaneously. Further analysis of the interference between dual-DMOE shows that the interference is much less than that of a conventional dual-microlens. It is indicated that the designed micro-optical element array can not only implement hollow beam and dual focus, but also suppress the interference effect significantly.

• 出版日期2008-10
• 单位北京交通大学