Electro-optically controlled photon group velocity, temporal walk-off and two-photon entanglement via nematic liquid crystal

TL;DR

This paper develops a theoretical framework for controlling quantum light propagation in nematic liquid crystals, enabling tunable manipulation of photon timing, polarization, and entanglement for quantum information applications.

Contribution

It introduces a unified model incorporating dispersion and birefringence in liquid crystals, allowing electrical control over quantum photon properties.

Findings

Nematic liquid crystals can be used as electrically tunable quantum photonic devices.

Analytical expressions for group velocity and temporal walk-off are derived.

The framework demonstrates control over entangled photon pair properties.

Abstract

The propagation of the quantum states of light in dispersive and anisotropic media is a fundamental problem in quantum optics. We present a unified theoretical framework for the propagation of the quantum states of light in voltage-controlled nematic liquid crystals, incorporating both material dispersion and electrically tunable birefringence. By treating photons as finite-bandwidth wave packets, we derive analytical expressions for group velocoity, temporal walk-off, and phase evolution of orthogonally polarized modes. The results demonstrate that nematic liquid crystals can serve as electrically tunable quantum photonic devices capable of manipulating photon arrival times, polarization correlations, and temporal indistinguishability of entangled photon pairs. These results show the direct relevance to quantum communication and photonic quantum information processing.