Electrically tunable two-dimensional liquid crystals gratings induced by polarization holography

Area of Science:

• Materials Science
• Optics
• Polymer Science

Background:

• Photoaligning substrates enable the creation of complex polarization holograms.
• Azo-dye doped polyimides are sensitive to light polarization, facilitating recording processes.

Purpose of the Study:

• To develop a method for fabricating two-dimensional (2D) gratings with tunable optical properties.
• To investigate the light diffraction characteristics and polarization states of the fabricated 2D gratings.
• To demonstrate optical and electrical control over the diffracted light energy distribution.

Main Methods:

• Recording 1D polarization holograms on photoaligning substrates using interference of circularly polarized beams.
• Crossed assembly of 1D holograms to form 2D gratings with twisted nematic structures.
• Irradiation of the 2D gratings with linearly polarized light to observe diffraction patterns.
• Application of external AC voltage to control diffracted energy distribution.

Main Results:

• Successfully fabricated 2D gratings composed of twisted nematic structures.
• Observed diffraction of light into different directions with distinct polarization states (circular and linear).
• Demonstrated simultaneous generation of orthogonal circularly and linearly polarized diffraction orders.
• Achieved complete control over the diffracted energy distribution using an external AC voltage.

Conclusions:

• The developed method allows for the creation of 2D gratings with controllable polarization-dependent diffraction.
• These novel gratings offer a versatile platform for advanced optical manipulation and display technologies.
• The ability to electrically tune the diffraction efficiency opens possibilities for dynamic optical devices.