Observation of helical pulses.

Area of Science:

• Physics
• Optics
• Wave Phenomena

Background:

• Ultrafast spatiotemporal vortex pulses are a type of spatiotemporal topological wave.
• Experimental generation of helical pulses, specifically single- or few-cycle short vortex pulses with space-time nonseparability, has been a significant challenge.

Purpose of the Study:

• To introduce and demonstrate two complementary experimental methods for generating space-time nonseparable helical pulses (SNHPs).
• To achieve SNHPs in both optical and microwave spectral regimes.

Main Methods:

• Generated few-cycle quasi-linearly polarized SNHPs by decomposing optical toroidal pulses into their polarization components.
• Produced single-cycle non-transverse SNHPs directly using a microwave ultrawideband spiral emitter.

Main Results:

• Successfully demonstrated the experimental generation of space-time nonseparable helical pulses (SNHPs).
• Achieved SNHPs in both optical and microwave domains, including few-cycle and single-cycle pulses.

Conclusions:

• The developed methods enable the experimental realization of SNHPs.
• These findings provide a foundation for exploring SNHP properties and applications, including light-matter interactions and optical communications.