Abstract
Established diffractive optical elements (DOEs), such as Dammann gratings, whose phase profile is controlled by etching different depths into a transparent dielectric substrate, suffer from a contradiction between the complexity of fabrication procedures and the performance of such gratings. In this Letter, we combine the concept of geometric phase and phase modulation in depth, and prove by theoretical analysis and numerical simulation that nanorod arrays etched on a silicon substrate have a characteristic of strong polarization conversion between two circularly polarized states and can act as a highly efficient half-wave plate. More importantly, only by changing the orientation angles of each nanorod can the arrays control the phase of a circularly polarized light, cell by cell. With the above principle, we report the realization of nanorod-based Dammann gratings reaching diffraction efficiencies of 50%–52% in the C-band fiber telecommunications window (1530–1565 nm). In this design, uniform spot arrays with an extending angle of can be obtained in the far field. Because of these advantages of the single-step fabrication procedure, accurate phase controlling, and strong polarization conversion, nanorod-based Dammann gratings could be utilized for various practical applications in a range of fields.
© 2015 Optical Society of America
Full Article | PDF ArticleMore Like This
Xiaoran Zheng, Jiaqi Yang, Runqiu Wang, and Tian Lan
Appl. Opt. 61(9) 2184-2191 (2022)
Yifeng Yang, Houkang Liu, Ye Zheng, Man Hu, Chi Liu, Yunfeng Qi, Bing He, Jun Zhou, Yunrong Wei, and Qihong Lou
Opt. Lett. 39(3) 708-710 (2014)
Xiao-Qian Wang, Abhishek Kumar Srivastava, Fan Fan, Zhi-gang Zheng, Dong Shen, Vladimir Grigorievich Chigrinov, and Hoi-Sing Kwok
Opt. Lett. 41(24) 5668-5671 (2016)