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Accurate THz ellipsometry using calibration in time domain

Zahra Mazaheri, Can Koral & Antonello Andreone
Scientific Reports
12,
7342
(2022)
Open access
© The Author(s) · CC BY 4.0
First page of Mazaheri et al. 2022, Scientific Reports
Mazaheri et al. (2022)
Scientific Reports 12, 7342
Read the published paper

Research overview

This paper presents a customised terahertz time-domain spectroscopic ellipsometer (THz-TDSE) for accurate material characterisation over a wide range of incidence angles. The fibre-coupled system incorporates three free-standing wire-grid polarizers and an algorithm-assisted time-domain calibration method to compensate for imperfect antenna and polarizer response, imprecise angular positioning and mismatches in the THz beam optics. Measurements on solid and liquid samples demonstrated good agreement with conventional THz time-domain spectroscopy, showing the potential of calibrated THz ellipsometry for characterising highly absorptive materials that are difficult to investigate in transmission.

Key findings

  • Variable-angle THz time-domain ellipsometry over approximately 0.1–0.6 THz
  • Three free-standing wire-grid polarizers used as polarizer, analyzer and compensator
  • Algorithm-assisted calibration compensates polarization and optical-system non-idealities
  • Measurements validated on solid and liquid materials against conventional THz spectroscopy
Purewavepolarizer 10 micron wire grid polarizer image

10 µm Tungsten Wire-Grid Polarizer

Free-standing tungsten wire-grid polarizer used for broadband THz polarization control. Three polarizers were employed in the ellipsometer as polarizer, analyzer and compensator.
View product configurations
“For the control and detection of the polarization states we employ three substrate free Wire Grid Polarizers (WGP) from PureWavePolarizers Ltd, with broadband transmission and high extinction ratio ranging between 20 and 50 dB.”
Mazaheri et al.,
2022

Publication details

Journal

Scientific Reports

Volume

12

Issue

–

Article

7342

Published

2022

Research area

Instrumentation and Metrology

Application

THz ellipsometry and material characterisation

Licence

© The Author(s) · CC BY 4.0

Institution

University of Naples Federico II / INFN Naples

DOI

https://doi.org/10.1038/s41598-022-10804-w

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