Dynamic Response of a fast near infra-red Mueller matrix ellipsometer

TL;DR

This paper investigates the dynamic response of a near-infrared Ferroelectric Liquid Crystal Mueller matrix ellipsometer, modeling its temporal behavior and identifying the switching time as the measurement speed limit, with potential for faster operation.

Contribution

It presents a simulation model incorporating measured responses of FLCs and detectors to analyze the system's dynamic behavior and maximum measurement speed.

Findings

Maximum measurement speed of approximately 16 ms per Mueller matrix.

Switching time of FLCs is the limiting factor for measurement speed.

Demonstrated temporal response of Mueller matrix and retardance changes.

Abstract

The dynamic response of a near infrared Ferroelectric Liquid Crystal based Mueller matrix ellipsometer (NIR FLC-MME) is presented. A time dependent simulation model, using the measured time response of the individual FLCs, is used to describe the measured temporal response. Furthermore, the impulse response of the detector and the pre-amplifier is characterized and included in the simulation model. The measured time-dependent intensity response of the MME is reproduced in simulations, and it is concluded that the switching time of the FLCs is the limiting factor for the Mueller matrix measurement time of the FLC-based MME. Based on measurements and simulations our FLC based NIR-MME system is estimated to operate at the maximum speed of approximately 16 ms per Mueller matrix measurement. The FLC-MME may be operated several times faster, since the switching time of the crystals depends on the individual crystal being switched, and to what state it is switched. As a demonstration, the measured temporal response of the Mueller matrix and the retardance of a thick liquid crystal variable retarder upon changing state is demonstrated.