Hybrid polarization grating for mode detection of vector beams

Area of Science:

• Optics and Photonics
• Liquid Crystal Devices
• Vector Beam Manipulation

Background:

• Vector beams possess complex polarization structures crucial for advanced optical applications.
• Current methods for separating vector beam states can be complex and bulky.
• Efficient spatial separation of orthogonal vector beam states with identical topological charges is challenging.

Purpose of the Study:

• To present a hybrid polarization grating for spatially separating orthogonal vector beam states.
• To demonstrate the device's ability to handle vector beams with the same polarization topological charge.
• To explore its potential for vector beam division multiplexing and detection.

Main Methods:

• Assembly of a hybrid polarization grating by combining a fork-shaped polarization grating and a quarter-wave polarization grating.
• Utilizing the device as a common-pass interferometer for right- and left-circularly polarized components.
• Experimental fabrication using the photoalignment method for photoreactive liquid crystals.

Main Results:

• The hybrid polarization grating successfully separates two vector beam states with a 90° relative polarization azimuth angle difference.
• A crossed-hybrid polarization grating configuration allows for an increased number of detectable vector beams.
• Experimental validation confirmed the feasibility of both hybrid and crossed-hybrid polarization gratings.

Conclusions:

• The developed hybrid polarization grating offers a stable and simultaneous method for demultiplexing vector beams.
• The compact optical system has significant potential for vector beam division multiplexing.
• This technology is applicable to various applications requiring precise vector beam detection and manipulation.