Multi-focus lens based on metasurface holography
Yuxuan Jia;Qi Fan;Yunfei Wang;College of Science, Air Force Engineering University;
A broadband multi-focus lens based on metasurface holography in the far-infrared region is designed. By designing 8 C-shaped resonant rings, when linearly polarized light waves are incident normally to this set of resonators,cross-polarized component of transmitted light will form the phase shift from 0 to 2π, meanwhile the amplitude transmittance remains constant. Full-wave simulation was utilized to verify anomalous refraction properties when linearly polarized light waves irradiated this set of resonators vertically. The phase distribution of multi-focus lens was obtained by adopting the computer-generated hologram(CGH) method. According to arranged resonant rings based on the calculated phase distribution, a squared multi-focus lens based on metasurface was obtained.Simulation for the designed lens was conducted. Results show a good multi-focusing performance at the central frequency 28 THz in the focal length of 108 μm.