Fractional topological charge measurement through optical correlation.

Area of Science:

• Optics and Photonics
• Quantum Information Science

Background:

• Optical vortex beams with fractional topological charges (TCs) are crucial for advanced applications.
• Precise measurement of orbital angular momentum (OAM) linked to fractional TCs is essential for harnessing their potential.

Purpose of the Study:

• To introduce a novel, simple, and efficient technique for measuring the fractional TC of optical vortex beams.
• To provide a computationally inexpensive and real-time implementable alternative to complex machine learning methods.

Main Methods:

• Utilizing a hybrid digital-optical correlator.
• Employing auto-correlation of fork-shaped interference patterns for both integer and fractional TCs.

Main Results:

• Demonstration of a new method for fractional TC measurement.
• Achieved real-time implementation with reduced computational cost.

Conclusions:

• The proposed hybrid digital-optical correlator offers a practical solution for measuring fractional TCs.
• This technique simplifies OAM information extraction, benefiting diverse optical applications.