Quasi-perfect spatiotemporal optical vortex with suppressed mode degradation

TL;DR

This paper introduces mode degradation-suppressed spatiotemporal optical vortices (MDS-STOVs), which maintain their structure during propagation, are resistant to dispersion, and are promising for advanced optical communication and quantum information applications.

Contribution

The study proposes a method to generate quasi-perfect STOVs with suppressed mode degradation using a conical phase, enhancing stability and dispersion resistance.

Findings

MDS-STOVs maintain ring-shaped profiles at high topological charges.

Rapid beam expansion with increasing topological charge is significantly suppressed.

QPS-STOVs exhibit strong resistance to group delay dispersion.

Abstract

Spatiotemporal optical vortex (STOV) carrying transverse orbital angular momentum (OAM) enriches the family of vortex beams and exhibit unique properties. Typically, a high-order STOV with an intensity null degrades into multiple first-order STOVs embedded within a single wave packet during propagation, a phenomenon known as time diffraction or mode degradation. However, this degradation limits the applicability of STOVs in specialized fields. Therefore, the generation of mode degradation-suppressed STOVs (MDS-STOVs) is of significant for both practical applications and theoretical studies. Herein, we theoretically analyze the generation of MDS-STOVs by utilizing a conical phase to localize the energy of the STOV into a ring-shaped structure. For MDS-STOVs with large topological charges (TCs), the ring-shaped profile can be well-maintained, and the rapid expansion of the beam size with increasing TC is significantly suppressed compared to conventional STOVs. As a result, these MDS-STOVs can be regarded as quasi-perfect STOVs (QPSTOVs). Furthermore, QPSTOVs exhibit strong resistance to group delay dispersion (GDD), eliminating the need for precise dispersion control and facilitating their generation and application. This work advances our understanding of the physical properties of light carrying transverse OAM and opens up exciting avenues for the application of STOVs in diverse fields, such as optical communication and quantum information processing.