Accurate polarization preparation and measurement using twisted nematic liquid crystals.

Area of Science:

• Photonics and Optical Engineering
• Quantum Information Science

Background:

• Precise control and measurement of light polarization are crucial for optical metrology, communications, imaging, and information processing.
• Existing liquid crystal devices offer limited precision and require custom designs, hindering practical applications.

Purpose of the Study:

• To develop a fast and accurate method for preparing and detecting light polarization states.
• To overcome the limitations of conventional liquid crystal devices for polarization control.

Main Methods:

• Utilizing liquid-crystal cells from common twisted nematic liquid-crystal displays for polarization state preparation and detection.
• Employing four-projection minimum tomography and six-projection Pauli measurements for polarization state analysis.
• Applying the maximum likelihood method for processing polarization measurement data.

Main Results:

• Achieved unprecedented accuracy in preparing dozens of polarization states with an average fidelity of 0.999(1) and angle deviation of 0.5(3) degrees.
• Demonstrated high-fidelity polarization measurement (average fidelity 0.999(1)) using the developed device.
• Successfully applied the liquid-crystal device for full tomographic characterization of a three-mode Greenberger-Horne-Zeilinger entangled state.

Conclusions:

• The developed liquid-crystal device offers a practical and highly accurate solution for polarization state preparation and measurement.
• This technology has significant implications for advancing classical polarimetry and quantum information processing.
• The use of readily available liquid-crystal display components makes this approach cost-effective and broadly applicable.