Optical vortex transfer and dispersion-controlled light propagation in an Er³⁺: YAG three-level quantum system

Area of Science:

• Quantum Optics
• Solid-State Photonics
• Nonlinear Optics

Background:

• Coherent manipulation of light's orbital angular momentum (OAM) is crucial for advanced optical technologies.
• Erbium-doped YAG (Er³⁺: YAG) is a promising material for laser applications but its use in OAM manipulation is underexplored.

Purpose of the Study:

• To investigate coherent OAM transfer and dispersion-controlled light propagation in a ladder-type Er³⁺: YAG three-level system.
• To determine the optimal Er³⁺ concentration for efficient vortex transfer.
• To explore the potential for concentration-selectable light propagation regimes.

Main Methods:

• Utilized density-matrix formalism and coupled Maxwell-Bloch equations.
• Derived analytical expressions for probe and generated beams, incorporating Er³⁺ ion concentration.
• Analyzed conversion efficiency, spatial phase, and intensity distributions.

Main Results:

• Demonstrated efficient OAM transfer from a probe beam to a generated signal beam with complete phase and topological-charge preservation.
• Identified an optimal Er³⁺ concentration of 3% for maximizing vortex-transfer efficiency.
• Revealed concentration-selectable transitions between fast and slow light propagation regimes.

Conclusions:

• Er³⁺: YAG serves as a viable solid-state platform for coherent OAM manipulation and structured light generation.
• The study highlights potential applications in OAM-based communication, wavelength-compatible OAM interfaces, and slow-light processing.