Specular and antispecular light beams

Area of Science:

• Optics and Photonics
• Laser Physics
• Coherent Beam Generation

Background:

• Partially coherent light beams are crucial in various optical applications.
• Gaussian Schell-model beams are a common type of partially coherent source.
• Controlling beam structure and coherence is an ongoing research area.

Purpose of the Study:

• To investigate a new class of partially coherent beams generated via wavefront folding.
• To analyze the propagation characteristics and internal structure of these beams.
• To experimentally demonstrate and measure the spatial coherence of these novel beams.

Main Methods:

• Generating partially coherent beams by passing a Gaussian Schell-model beam through a wavefront-folding interferometer.
• Analyzing beam propagation and shape invariance.
• Experimentally demonstrating the beams using a digital micromirror device.
• Measuring the complex degree of spatial coherence.

Main Results:

• Demonstrated shape-invariant partially coherent beams on propagation.
• Observed distinct internal structures: specular beams with central peaks and antispecular beams with central dips.
• Showed that beam dimensions are dependent on the spatial coherence area.
• Measured cross-like spatial coherence distributions experimentally.

Conclusions:

• Wavefront folding of Gaussian Schell-model beams produces novel, shape-invariant partially coherent beams.
• The internal structure (peak or dip) and dimensions are controllable via spatial coherence.
• Experimental validation confirms the theoretical predictions and highlights the utility of digital micromirror devices for coherence measurements.