Introducing Berry phase gradients along the optical path via propagation-dependent polarization transformations.

Area of Science:

• Quantum optics
• Wave propagation physics

Background:

• The Berry phase is a topological phase acquired by quantum systems during cyclic evolution.
• The Gouy phase is a known manifestation of the Berry phase in wave optics, related to wavefront curvature changes.

Purpose of the Study:

• To report a novel manifestation of the Berry phase in three-dimensional (3D) structured light.
• To investigate the accumulation of phase shifts due to adiabatic evolution of polarization along the optical path.

Main Methods:

• Studying the adiabatic evolution of polarization states in 3D structured light during free-space propagation.
• Analyzing the accumulated phase shift and its relation to Berry's phase prediction.

Main Results:

• Observed a new Berry phase in 3D structured light arising from polarization evolution.
• Demonstrated that this phase accumulates differently from conventional dynamic phases.
• Showed the Berry phase can be engineered on demand.

Conclusions:

• The findings expand the understanding of wave propagation laws.
• This engineered Berry phase enables applications like spin-dependent spatial frequency shifts.
• Potential applications include modified phase matching in optical resonators and nonlinear interactions.