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Lagging propagation phase of spatially structured beams.
Optics Express
|December 13, 2023
Summary
Structured beams exhibit a "lagging propagation phase," a novel concept extending the Gouy phase. This finding, observed in higher-order Bessel beams, offers new insights into beam dynamics and applications.
Area of Science:
- Optics and Photonics
- Wave Physics
Background:
- Structured light beams with spatially varying phase are crucial in physics and engineering.
- Previous research indicated modifications to group velocity due to spatial confinement, but experimental data on phase velocity remained limited.
Purpose of the Study:
- To develop a theoretical model and provide experimental validation for the propagation phase of structured beams.
- To investigate the phenomenon of a
- lagging propagation phase
- in structured light.
Main Methods:
- Theoretical modeling of structured beam propagation.
- Experimental observation using higher-order Bessel beams.
- Analysis of intensity pattern rotations to map phase differences.
Main Results:
- Demonstrated that structured beams with a specific axial wavevector component possess a lagging propagation phase.
- Established this lagging phase as a generalization of the Gouy phase.
- Quantified the phase difference by correlating intensity pattern rotation with radial and angular phase gradients.
Conclusions:
- The lagging propagation phase offers a physical interpretation for the dynamic evolution of complex structured beams, including vortex knots and braids.
- This phenomenon has potential applications in optical sensing and metrology, enhancing structured beam technologies.
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