In our new work published in Optics Express, we present a calibration method for twisted nematic liquid crystals (TNLCs) that allows accurate polarization manipulation. The calibration method does not require knowledge of parameters or a model of the constituent TNLC cells. Data, code, and other supplementary materials are publicly available at GitHub repository.

We demonstrate the preparation and measurement of polarization states using a three-cell twisted nematic liquid crystal device with an average fidelity of 0.999(1).

The time required to perform the full polarization tomography of a single polarization mode (single qubit) is an order of magnitude faster than using a reference waveplate-based polarimeter at the same level of accuracy. We have performed the full tomography of 3-qubit photonic entangled state using the reported device.

Accurate polarimetry with liquid crystals