Evolution of coherence singularities of Schell-model beams.

Area of Science:

• Optics and Photonics
• Coherent Beam Propagation
• Partial Coherence Theory

Background:

• Schell-model beams (SMBs) are widely used partially coherent beams.
• Analyzing mutual intensity and coherence singularities in SMBs is complex.
• Associated coherent beams include Laguerre-, Hermite-, and Ince-Gaussian types.

Purpose of the Study:

• To demonstrate the utility of the ambiguity function for analyzing SMB propagation.
• To investigate the evolution of coherence singularities in SMBs.
• To establish the relationship between input beam properties and singularity characteristics.

Main Methods:

• Application of the ambiguity function to model SMB propagation.
• Analysis of mutual intensity evolution.
• Study of coherence singularity formation and far-field behavior.

Main Results:

• The ambiguity function provides a simplified framework for understanding SMB propagation.
• The distance of coherence singularity formation is dependent on the input beam's coherence degree.
• The far-field characteristics (shape, position, number) of singularity curves are determined by the associated coherent beam.

Conclusions:

• The ambiguity function is an effective tool for analyzing partially coherent light, specifically SMBs.
• Understanding coherence singularities in SMBs can be achieved through this approach.
• The study clarifies the factors governing singularity formation and far-field patterns.