Robotized polarization characterization platform for free-space quantum communication optics

TL;DR

This paper presents a robotic platform with an imaging polarimeter for precise polarization characterization of optical devices in free-space quantum communication, enabling versatile and accurate measurements at any position.

Contribution

The development of a robotic polarization characterization platform with integrated imaging polarimeter and detailed error analysis for free-space quantum optics applications.

Findings

Validated polarization measurement accuracy with a silver-coated mirror.

Demonstrated polarization testing on a quantum optical lens for QEYSSat.

Quantitative agreement between theoretical models and experimental results.

Abstract

We develop a polarization characterization platform for optical devices in free-space quantum communications. We demonstrate an imaging polarimeter, which analyzes both incident polarization states and the angle of incidence, attached to a six-axis collaborative robot arm, enabling polarization characterization at any position and direction with consistent precision. We present a detailed description of each subsystem including the calibration and polarization-test procedure, and analyze polarization-measurement errors caused by imperfect orientations of the robot arm using a Mueller-matrix model of polarimeters at tilt incidence. We perform a proof-of-principle experiment for an angle-dependent polarization test for a commercial silver-coated mirror for which the polarization states of the reflected light can be accurately calculated. Quantitative agreement between the theory and experiment validates our methodology. We demonstrate the polarization test for a 20.3 cm lens designed for a quantum optical transmitter in Canada's Quantum Encryption and Science Satellite (QEYSSat) mission.