Mode Structure and Orbital Angular Momentum of Spatiotemporal Optical Vortex Pulses

Area of Science:

• Optics and Photonics
• Electromagnetism
• Quantum Optics

Background:

• Spatiotemporal optical vortices (STOV) are complex light fields with unique properties.
• Understanding the behavior of STOVs in dispersive media is crucial for optical applications.
• Orbital angular momentum (OAM) in light has garnered significant research interest.

Purpose of the Study:

• To identify and characterize modal solutions for STOV electromagnetic pulses in dispersive media.
• To investigate the quantization of orbital angular momentum (OAM) for these STOV solutions.
• To explore the potential existence of associated quasiparticles during STOV propagation.

Main Methods:

• Theoretical derivation of modal solutions for STOV pulses.
• Analysis of OAM properties in vacuum and dispersive media.
• Comparison of theoretical predictions with experimental measurements of free-space STOV propagation.

Main Results:

• Identified a class of modal solutions for STOV pulses in dispersive media.
• Demonstrated that symmetric STOVs in vacuum carry half-integer intrinsic OAM.
• Found that asymmetric STOVs in dispersive media exhibit OAM quantized in integer multiples dependent on symmetry and group velocity dispersion.
• Proposed the existence of a polaritonlike quasiparticle accompanying STOVs in dispersive media.
• Modal theory showed excellent agreement with experimental free-space propagation measurements.

Conclusions:

• The study provides a comprehensive modal theory for STOV propagation in dispersive media.
• Novel insights into the quantization of OAM for STOVs are presented.
• The findings suggest a new perspective on light-matter interaction via polaritonlike quasiparticles.