Sensitive voltage-dependent diffraction of a liquid crystal Fresnel lens

Area of Science:

• Optics and Photonics
• Materials Science
• Electrical Engineering

Background:

• Liquid crystals (LCs) are widely investigated for tunable optical applications.
• Developing efficient and low-power optical devices remains a key challenge in photonics.

Purpose of the Study:

• To propose and demonstrate a Fresnel liquid crystal (LC) lens with high diffraction efficiency.
• To achieve a low driving voltage for the LC lens operation.
• To explore the electrical modulation of optical properties using LC-based Fresnel lenses.

Main Methods:

• Fabrication of a Fresnel zone electrode on a glass plate.
• Induction of a Fresnel zone-distributed electric field within the LC cell using a driving voltage.
• Characterization of the LC lens's diffraction efficiency using a polarized incident beam (632.8 nm wavelength).

Main Results:

• Achieved a remarkable diffraction efficiency of approximately 39%, nearing the theoretical limit of 40.5%.
• Demonstrated sensitive dependence of diffraction efficiency on the applied voltage.
• Identified a low optimal driving voltage of 0.9 V for the Fresnel LC lens.

Conclusions:

• The proposed Fresnel LC lens exhibits high performance in terms of diffraction efficiency and low power consumption.
• The study highlights the potential for electrical control over optical properties in various systems.
• This work paves the way for advancements in tunable optical components and systems.