High-efficiency, four-channel beam splitter based on a fishnet-shaped continuous metasurface

Area of Science:

• Nanophotonics and Metasurfaces
• Integrated Optics

Background:

• Beam splitters are crucial optical components, but miniaturization for integrated optical circuits demands nanoscale solutions.
• Existing beam splitters often lack the efficiency and multi-channel capabilities required for advanced optical systems.

Purpose of the Study:

• To propose and numerically demonstrate a broadband, high-efficiency, four-channel beam splitter using a fishnet-shaped metasurface.
• To achieve miniaturized beam splitting for integrated optical circuits.

Main Methods:

• Numerical demonstration of a fishnet-shaped metasurface composed of cruciform aluminum antimonide (AlSb) nanoantennas on a polydimethylsiloxane (PDMS) substrate.
• Analysis of beam splitting efficiency, anomalous transmission, and beam splitting angles across a specified wavelength range.

Main Results:

• The proposed metasurface achieves a conversion efficiency above 83% and anomalous transmission exceeding 0.8 for wavelengths between 761-835 nm.
• The device splits light into four equal-intensity beams with a tunable splitting angle ranging from 46.45° to 53.68° within the broadband range.
• The beam splitting angle is further tunable by stretching the substrate, demonstrating adjustability from 56.34° to 46.39° at 874 nm.

Conclusions:

• The developed metasurface offers a promising solution for multi-channel, broadband, high-efficiency beam splitting in a compact form factor.
• This technology has potential applications in advanced integrated optical devices and systems.
• The tunable nature of the beam splitter enhances its versatility for various optical applications.