Design and fabrication of birefringent nano-grating structure for circularly polarized light emission

High-Efficiency and Wide-Angle Versatile Polarization Controller Based on Metagratings

Metamaterials with their customized properties enable us to efficiently manipulate the polarization states of electromagnetic waves with flexible approaches, which is of great significance in various realms. However, most current metamaterial-based polarization controllers can only realize single function, which has extremely hindered the expansion of their applications. Here, we experimentally demonstrate highly efficient and multifunctional polarization conversion effects using metagrating by integrating single-structure metallic meta-atoms into the dielectric gratings. Benefiting from the combined advantages of the gratings and the metamaterials, the considered metagrating can operate in transmission and reflection modes simultaneously, acting as a high-performance and wide-angle quarter-wave or half-wave plate with distinct functions in different frequency bands. This metagrating structure is scalable to other frequency ranges and may provide opportunities to design compact multifunctional optical polarization control devices.

All-metal flexible large-area multiband waveplate

We propose and demonstrate an all-metal flexible reflective multiband waveplate based on nano-grating structure using high efficient electroplating growing process, which exhibits quarter waveplate at two wavelengths (λ = 465nm and λ = 921nm) and half waveplate at another wavelength (λ = 656nm). Using Finite Difference Time Domain (FDTD) modeling, the phase shift and reflection efficiency are simulated and designed for a variety of geometrical parameters. A fast and cost-effective technique based on conventional interference lithography and nickel electroplating process is demonstrated to fabricate the all-metal, large-area and flexible waveplate. Experimental results show that the fabricated monolithic all-metal nano structure of the proposed device are in high fidelity with the structure on template and the optical performance of the device are in excellent agreement with the theoretical prediction. The proposed structure and the fabrication method suggests an effective way to realize all-metal, ultrathin, self-supporting and flexible devices for various applications in rugged environment such as high temperature or high pressure environment, and also in the fast growing fields of flexible (wearable) optoelectronics, flexible displays and other curved or nonplanar devices.