High efficiency and large angle polarization independent beam deflection metagrating by Bayesian optimization

Area of Science:

• Nanophotonics and Metamaterials
• Optical Engineering
• Computational Physics

Background:

• Directional emission sources are crucial for advanced technologies like 3D displays and optical communication.
• Existing metasurfaces often struggle with polarization independence and limited deflection angles, hindering broader applications.
• Compact directional emission sources require efficient beam deflection technologies.

Purpose of the Study:

• To propose a novel nanorod-based two-dimensional metagrating for polarization-independent beam deflection.
• To achieve large deflection angles (30-75 degrees) with high efficiency for unpolarized light.
• To develop an efficient optimization method for metagrating design.

Main Methods:

• Design of a nanorod-based two-dimensional metagrating structure.
• Implementation of a Bayesian optimization algorithm for global optimization of metagrating parameters.
• Performance evaluation of beam deflection angle and efficiency for unpolarized incident light.

Main Results:

• Demonstrated a polarization-independent metagrating capable of large deflection angles from 30 to 75 degrees.
• Achieved a maximum beam deflection efficiency of 90.1%.
• The Bayesian optimization method showed faster convergence and superior performance compared to particle swarm optimization.

Conclusions:

• The proposed nanorod-based metagrating effectively enables polarization-independent directional emission with large deflection angles.
• The developed Bayesian optimization method offers an efficient approach for designing advanced meta-devices.
• This work provides valuable insights for the development of polarization-independent functional meta-devices.