Optical vortices produced with a nonspiral phase plate

Area of Science:

• Optics and Photonics
• Laser Physics
• Wavefront Engineering

Background:

• Optical vortices are beams with a helical phase structure and a central phase singularity.
• Generating optical vortices typically requires spiral phase elements, which can be complex to fabricate.
• Understanding vortex generation is crucial for applications in optical trapping, microscopy, and information processing.

Purpose of the Study:

• To present simple, non-spiral methods for generating optical vortices.
• To demonstrate the creation of optical vortices on the beam propagation axis.
• To investigate the transformation of dislocations into optical vortices.

Main Methods:

• Utilizing nonspiral phase plates, specifically one providing linear phase retardation on half of the laser beam.
• Experimental demonstration using a thickness-varying glass platelet to implement the phase retardation.
• Analyzing the transformation of mixed dislocations from a bent edge dislocation.

Main Results:

• Successfully produced optical vortices on the beam axis using a simple phase plate.
• Experimentally verified the generation of optical vortices with a thickness-varying glass platelet.
• Demonstrated that mixed dislocations of a bent edge dislocation transform into a pair of optical vortices with opposite topological charges.

Conclusions:

• Nonspiral phase plates offer a straightforward method for generating optical vortices.
• The proposed technique provides an accessible route to optical vortex creation.
• The study elucidates the relationship between dislocation transformation and vortex generation.