Geometric phase shaping of terahertz vortex beams

Area of Science:

• Optics and Photonics
• Electromagnetism
• Materials Science

Background:

• Terahertz (THz) technology requires precise control over beam properties.
• Structured light, particularly vortex beams, offers unique capabilities for THz applications.
• Developing versatile methods for generating and manipulating THz beams is crucial.

Purpose of the Study:

• To propose and demonstrate a topological beam-shaping strategy for terahertz beams.
• To utilize geometric phase elements with space-variant birefringence for beam control.
• To generate and characterize terahertz vortex beams and their superpositions.

Main Methods:

• Employing geometric phase elements made of space-variant birefringent slabs.
• Producing quasi-monochromatic terahertz vortex beams.
• Characterizing beam amplitude and phase via real-time 2D electric field imaging.
• Obtaining and analyzing nonseparable superpositions of vortex beams using 2D polarimetric analysis.

Main Results:

• Successful generation of terahertz vortex beams with controlled amplitude and phase.
• Demonstration of real-time 2D imaging for electric field reconstruction.
• Creation and characterization of nonseparable superpositions of terahertz vortex beams.
• Validation of polarization-controlled orbital angular momentum content.

Conclusions:

• The proposed topological beam-shaping strategy is versatile for on-demand structured light generation in the THz domain.
• Geometric phase elements offer effective control over terahertz beam properties.
• The developed techniques are promising for future terahertz technologies requiring tailored light fields.