Observation of singularities in multiply scattered microwave fields

Area of Science:

• Physics
• Optics
• Wave phenomena

Background:

• Speckle patterns arise from wave interference in complex media.
• Understanding singularities in wave fields is crucial for characterizing wave propagation.

Purpose of the Study:

• To investigate the core structures of phase and polarization singularities in multiply scattering microwave fields.
• To validate theoretical predictions regarding the behavior of equiphase lines and singularities.

Main Methods:

• Applying the sampling theorem to measurements of orthogonal microwave field components.
• Analyzing speckle patterns generated by multiply scattering samples.

Main Results:

• Obtained speckle patterns at arbitrary resolution.
• Observed phase singularities, phase critical points, and polarization singularities.
• Equiphase lines connect phase singularities of opposite signs, with bifurcation lines passing through saddle points.
• Observed hyperbolic and elliptical equiphase lines around saddle and extremum points, respectively.
• Confirmed the existence of three predicted morphologies of polarization singularities.

Conclusions:

• The study confirms theoretical predictions about the structure of wave fields in multiply scattering media.
• Demonstrates the utility of speckle pattern analysis for exploring wave singularities.
• Provides experimental evidence for the complex topological structures within scattered wave fields.