Arbitrary geometry electromagnetic spatiotemporal vortices from phase velocity shearing.

Area of Science:

• Optics and Photonics
• Electromagnetism
• Fluid Dynamics Analogy

Background:

• Vortices in fluids arise from velocity differences at boundaries.
• Spatiotemporal optical vortices (STOVs) are analogous phenomena in light propagation.

Purpose of the Study:

• To demonstrate a novel method for generating arbitrary spatiotemporal optical vortices.
• To explore the creation of complex light geometries and phenomena.

Main Methods:

• Utilizing pulsed electromagnetic waves (specifically THz light) interacting with media of different phase velocities.
• Employing simple planar prints from commercial 3D printers to define light paths.
• Investigating the effect of relative time-delay between light pulses and media properties.

Main Results:

• Successfully generated STOVs with arbitrary geometries (squares, triangles, curves) not achievable with existing techniques.
• Demonstrated simultaneous formation of multiple ring and line vortices exhibiting complex reconnections.
• Validated the applicability of the method to THz frequencies with potential for visible and infrared light.

Conclusions:

• The developed technique offers a practical and straightforward method for generating arbitrary electromagnetic spatiotemporal vortices.
• This advancement enables the production of complex spatiotemporal phenomena, such as vortex reconnections.
• The theoretical framework aids in optimizing STOV generation for various light sources and frequencies.