Tailoring spatiotemporal wavepackets via two-dimensional space-time duality

TL;DR

This paper introduces a universal framework called two-dimensional space-time duality for analyzing and generating spatiotemporal wavepackets, enabling precise control and revealing new wavepacket types with high fidelity.

Contribution

It establishes the concept of space-time duality, develops a complex-amplitude modulation method, and uncovers new wavepacket regimes, advancing the understanding and manipulation of spatiotemporal light.

Findings

Achieved over 97% fidelity in crafting ST beams.

Uncovered a new range of ST wavepackets based on spatial-structure duality.

Highlighted the importance of balancing diffraction and dispersion for ST wavepacket dynamics.

Abstract

Space-time (ST) beams, ultrafast optical wavepackets with customized spatial and temporal characteristics, present a significant contrast to conventional spatial-structured light and hold the potential to revolutionize our understanding and manipulation of light. However, the progress in ST beam research has been constrained by the absence of a universal framework for their analysis and generation. Here, we introduce the concept of "two-dimensional ST duality", establishing a foundational duality between spatial-structured light and ST beams. We show that breaking the exact balance between paraxial diffraction and narrow-band dispersion is crucial for guiding the dynamics of ST wavepackets. Leveraging this insight, we pioneer a versatile complex-amplitude modulation strategy, enabling the precise crafting of ST beams with an exceptional fidelity exceeding 97%. Furthermore, we uncover a new range of ST wavepackets by harnessing the exact one-to-one relationship between scalar spatial-structured light and ST beams. Our findings suggest a paradigm shift opportunity in ST beam research and may apply to a broader range of wave physics systems.