Optical and Geometrical Properties from Terahertz Time-Domain Spectroscopy Data

Area of Science:

• Materials Science
• Spectroscopy
• Optics

Background:

• Terahertz (THz) waves offer non-destructive analysis of diverse materials.
• Terahertz time-domain spectroscopy (THz-TDS) is crucial for material property investigation.
• Extracting optical properties from THz-TDS signals traditionally requires sample geometry knowledge.

Purpose of the Study:

• To demystify and demonstrate THz-TDS signal analysis algorithms.
• To extract the complex refractive index for optically thin and thick samples.
• To elucidate the role of molecular structure in algorithm stability.

Main Methods:

• Applied spectral analysis algorithms to THz-TDS data from polymers and zinc telluride.
• Analyzed signals with and without Fabry-Pérot oscillations.
• Validated experimental results against published data.

Main Results:

• Successfully extracted the complex refractive index without prior thickness knowledge.
• Demonstrated algorithm stability across various polymer molecular structures.
• Identified the necessary conditions for observing Fabry-Pérot oscillations.

Conclusions:

• The study provides a clear methodology for THz-TDS data analysis.
• Understanding Fabry-Pérot oscillations is key for accurate optical property determination.
• Molecular structure influences the stability and applicability of THz-TDS algorithms.