Abstract
A metalens made of compact planar metastructure exhibits an excellent capability of focusing. The high-quality transmissive and reflective focusing simultaneously provides Fourier transform (FT) operation for optical information processing. Here we show a transflective on-chip metalens (TOM) made of orthogonal nano-grooves (ONGs). The TOM simultaneously converges transmitted and reflected (T&R) waves to the designed focal points. By adjusting the phase gradient profiles provided by the ONGs, the focal lengths of the T&R in-plane waves can be independently tuned. Our simulations show that the TOM possesses the advantages of broadband (>400 nm bandwidth) and high-focusing-efficiency (∼60%) dual-focusing capability. Further, we utilize the TOM to build a one-to-two 4-f optical system. Two different spatial filtering operations based on FT can be simultaneously implemented in axial transmission and off-axis reflection channels for one input signal. We expect that the dual-focusing metalens approach can realize parallel optical processing in on-chip optical computing, spatial filtering, and beyond.
© 2022 Optica Publishing Group
Full Article | PDF ArticleMore Like This
Han Xia, Tianyao Sheng, Jigen Ding, Mengmeng Li, and Yefeng Yu
Opt. Lett. 47(7) 1654-1657 (2022)
Zahrah Alnakhli, Ronghui Lin, Che-Hao Liao, Abdulrahman El Labban, and Xiaohang Li
Opt. Express 30(19) 34117-34128 (2022)
Dong-Qin Zhang, Yi Tao, Gui-Ming Pan, Zhong-Wei Jin, Bin Fang, Zhi Hong, and Fang-Zhou Shu
Opt. Lett. 47(23) 6073-6076 (2022)