Coherence-controlled azimuthal modulation of atomic ensemble susceptibility, grating, and Fraunhofer diffraction

Area of Science:

• Quantum Optics
• Atomic Physics
• Nonlinear Optics

Background:

• Electromagnetically induced transparency (EIT) enables optical switching and manipulation of light.
• Laguerre-Gaussian beams offer unique spatial and orbital angular momentum (OAM) properties.
• Controlling light-matter interactions in atomic ensembles is key for quantum technologies.

Purpose of the Study:

• To demonstrate coherence-controlled azimuthal modulation of EIT and all-optical switching.
• To investigate the influence of OAM and relative phase on EIT spatial patterns and diffraction.
• To explore the creation and properties of two-dimensional electromagnetically induced gratings (EIGs).

Main Methods:

• Utilizing a four-level atomic ensemble coupled to a Laguerre-Gaussian beam, a control field, and a microwave field.
• Modulating the relative phase of coupling fields to control EIT and absorption patterns.
• Analyzing spatial EIT structures (doublet, quartet, sextuplet) and their evolution with OAM.
• Investigating diffraction patterns from two-dimensional EIGs influenced by probe field detuning, OAM, and relative phase.

Main Results:

• Spatial EIT patterns exhibited doublet, quartet, and sextuplet structures, becoming complex with increasing OAM.
• Dynamic switching between EIT and absorption patterns was achieved, showing mirror and rotation symmetry based on OAM.
• Diffraction patterns from EIGs were influenced by probe detuning, OAM, and relative phase.
• Specific diffraction orders showed complex behavior dependent on topological charge and azimuthal angle, with relative phase controlling symmetry.

Conclusions:

• Coherence-controlled azimuthal modulation offers precise control over EIT and all-optical switching.
• The study demonstrates tunable diffraction patterns in atomic media, influenced by OAM and relative phase.
• Findings suggest potential for advanced optical devices utilizing structured light and coherent atomic interactions.