Electrically/optically tunable photo-aligned hybrid nematic liquid crystal Dammann grating

Area of Science:

• Optics and Photonics
• Materials Science
• Liquid Crystal Displays

Background:

• Dammann gratings (DGs) are crucial optical components for beam splitting.
• Traditional DGs often suffer from polarization dependence and complex fabrication.
• Liquid crystals (LCs) offer tunable optical properties suitable for advanced photonic devices.

Purpose of the Study:

• To develop a polarization-independent Dammann grating (DG) using hybrid photo-aligned nematic liquid crystals (LCs).
• To achieve high diffraction efficiency, fast response times, and low driving voltage.
• To explore the tunability and reconfigurability of the DG using optically active alignment layers.

Main Methods:

• Fabrication of a hybrid LC cell with homeotropic and patterned in-plane alignment substrates.
• Utilizing photo-aligned nematic LCs to create orthogonal alignment domains.
• Characterization of the DG's diffraction efficiency, response time, and driving voltage.

Main Results:

• The fabricated polarization-independent DG demonstrated an optical array with equally distributed energy.
• Achieved a diffraction efficiency exceeding 58%.
• Exhibited a response time of less than 1 ms and a low driving voltage of 3 V/μm.

Conclusions:

• The developed hybrid photo-aligned LC DG offers superior performance compared to conventional gratings.
• The optically active alignment layer enables optical tunability and reconfigurability.
• The DG's advantageous parameters make it suitable for various modern optical applications.