Thickness determination in anisotropic media with plasmon waveguide resonance imaging

Area of Science:

• Optics and Photonics
• Materials Science
• Surface Science

Background:

• Characterizing thin films, especially anisotropic ones, is crucial for advanced material applications.
• Existing methods for thickness determination can be complex or lack spatial resolution.
• Surface Plasmon Resonance (SPR) offers label-free optical sensing capabilities.

Purpose of the Study:

• To develop a straightforward optical procedure for determining local thickness of thin anisotropic layers.
• To differentiate between isotropic and anisotropic regions within a material.
• To validate the optical measurements against established techniques like Atomic Force Microscopy (AFM).

Main Methods:

• Utilizing Surface Plasmon Resonance (SPR) data acquired in an imaging mode.
• Employing the Kretschmann configuration for SPR measurements.
• Analyzing SPR data to infer layer thickness and anisotropy.

Main Results:

• A simple procedure for local thickness determination of thin anisotropic layers was established.
• The method successfully discriminated between isotropic and anisotropic regions under a smoothness hypothesis.
• Optical measurements showed good agreement with Atomic Force Microscopy (AFM) for thickness variation on an azobenzene modified polymer layer.

Conclusions:

• The developed SPR imaging method provides a simple and effective means for characterizing thin anisotropic layers.
• This technique offers a valuable tool for spatially resolved analysis of thin film properties.
• The findings demonstrate the utility of SPR for precise optical measurements in materials science.