Two-dimension high efficiency beam steering based on liquid crystal polarization gratings

Area of Science:

• Optics
• Materials Science
• Electrical Engineering

Background:

• Cascaded liquid crystal polarization grating (LCPG) structures enable large-angle, two-dimensional optical beam steering.
• Varying incident angles in cascaded LCPG systems reduce steering efficiency due to altered phase modulation by liquid crystal half-wave plates (LC HWPs).

Purpose of the Study:

• To analyze the steering efficiency of cascaded LCPGs under tilted incidence.
• To propose and validate a compensation method for enhancing steering efficiency in LCPG systems.

Main Methods:

• Developed a simple analysis model to calculate steering efficiency for cascaded LCPGs with arbitrary tilt incidence.
• Derived a compensation method to counteract the effect of tilt incidence on LC HWP phase modulation, including a formula for compensation voltage.
• Conducted validation experiments to verify the proposed compensation method.

Main Results:

• The analysis model accurately calculates steering efficiency under tilt incidence.
• The proposed compensation method effectively mitigates efficiency loss caused by tilted incidence.
• Simulated and experimental results confirm improved steering efficiency for two-dimensional beam scanning using cascaded LCPGs.

Conclusions:

• The developed compensation method significantly enhances the steering efficiency of cascaded LCPG structures under tilted incidence.
• This work provides a practical approach for high-efficiency two-dimensional beam steering using cascaded LCPGs.