Design and Analysis of Large-Angle Beam-Splitting Metagratings

SPIE Photonics West 2021, 6 – 11 March 2021
 

Metasurfaces that are composed of nanopillars with high refractive indices have great potential in different applications. Due to their unique capability in controlling and manipulating the electromagnetic fields, metagratings have been shown to have superior performance in comparison to those traditional gratings. Beam-splitting gratings are often employed in modern optical devices, for example, the LiDAR systems. Such gratings are often required to have large splitting angles and uniformly distributed power among all design orders, so to ensure high-precision acquisition of the depth information. Sometimes, the beam-splitting gratings must work with unpolarized light sources. Metagratings seem to be a good candidate for this task and we will present the design and analysis workflow of beam-splitting metagratings in the physical-optics software VirtualLab Fusion. That includes:

1. selection of the proper nanopillars as the building blocks / unit cells of the metagrating,
2. spatial distribution of the nanopillars,
3. parametric optimization of the whole metagrating structure, and
4. evaluation of its performance in a complete optical setup, including realistic light source and lenses.

Examples will be shown to explain the design and analysis technologies.