Generation of E-band metasurface-based vortex beam with reduced divergence angle

Area of Science:

• Optics and Photonics
• Wireless Communication Technology
• Metamaterials Science

Background:

• Vortex beams with orbital angular momentum (OAM) offer orthogonal modes for high-capacity wireless communication.
• Laguerre-Gaussian vortex beams face limitations due to increasing divergence with higher OAM mode orders.

Purpose of the Study:

• To develop metasurfaces capable of generating OAM vortex beams with reduced divergence angles.
• To enable practical applications of OAM multiplexing in the E-band frequency range.

Main Methods:

• Designing metasurfaces with meta-atom phase elements, including spiral phase and lens patterns.
• Incorporating a phase gradient array to mitigate source beam interference.
• Utilizing simulation and experimental measurements for validation.

Main Results:

• Metasurfaces with lens patterns significantly reduced vortex beam divergence.
• Divergence angle decreased from 13° to 9° for OAM mode l=1.
• Divergence angle decreased from 14° to 11° for OAM mode l=2.

Conclusions:

• Metasurfaces offer a viable solution for reducing vortex beam divergence in the E-band.
• The developed design methods advance OAM multiplexing applications, particularly at high frequencies.