Analysis of Bessel Beam Generation Using MetaMaterials in Photonic Integrated Circuits

TL;DR

This paper provides a detailed theoretical analysis and design of metasurface-based micro-photonic antennas capable of generating Bessel beams in the THz and optical ranges, with high efficiency and a non-diffracting range of 500 micrometers.

Contribution

It introduces a novel metasurface design and modeling approach for generating Bessel beams in integrated photonic circuits at multiple frequencies.

Findings

Achieved over 80% radiation efficiency.

Demonstrated non-diffracting range of 500 micrometers.

Validated models with simulations at optical and THz wavelengths.

Abstract

Bessel beams, known for their unique non-diffracting property, maintain their shape and intensity over long distances, making them invaluable for applications in optical trapping, imaging, and communications. This work presents a comprehensive theoretical analysis of micro-photonic antennas designed to generate Bessel beams within the Terahertz (THz) and optical frequency ranges. The technique is demonstrated by generating far-field patterns of Bessel waves at these frequencies. The design employs metasurface patterns arranged as arrays of concentric rings atop rectangular silicon waveguides, collectively creating a Bessel beam. Dyadic Greens function integral equation techniques are used to model the transverse electric (TE) and transverse magnetic (TM) fields in the metasurface radiation zone. Utilizing orthogonal vector wave functions, Bloch theorem, Floquet harmonics, and the transverse resonance technique, a photonic chip is designed to achieve a non-diffracting range of 500 um at the optical telecom wavelength of 1.5 um for a metasurface radius of 25 um. A radiation efficiency exceeding 80% is achieved by optimizing the attenuation constant (alpha) along the structure. The theoretical models are validated through simulations for both optical 1.5 um and Terahertz 14 um wavelengths, demonstrating significant alignment between predictions and simulation results.