Broadband wide-angle dispersion measurements: instrumental setup, alignment, and pitfalls

Area of Science:

• Optics and Photonics
• Nanotechnology
• Materials Science

Background:

• Surface Plasmon Resonance (SPR) is a powerful technique for characterizing nanostructures.
• Conventional SPR instruments often use monochromatic light sources, limiting dispersion analysis.
• Wide-angle measurements are crucial for understanding nanostructure optical properties.

Purpose of the Study:

• To present the construction, alignment, and performance of a novel broadband white light setup for wide-angle SPR measurements.
• To enable automated angle vs. wavelength dispersion measurements for arbitrary nanostructure arrays.
• To address and overcome challenges in aligning and operating such a system.

Main Methods:

• Utilized a broadband/white light source instead of a monochromatic one.
• Employed a cylindrical prism to minimize refraction-induced effects.
• Developed non-trivial alignment procedures for all angles of incidence.
• Investigated effects of finite beam width and sample substrate thickness.

Main Results:

• Demonstrated a functional setup for broadband wide-angle SPR measurements.
• Successfully performed automated angle vs. wavelength dispersion measurements.
• Provided experimental evidence validating the instrument's performance and alignment procedures.
• Identified and mitigated issues related to beam width and substrate thickness.

Conclusions:

• The developed instrument offers enhanced capabilities for nanostructure characterization using SPR.
• The novel setup facilitates comprehensive optical property analysis through automated dispersion measurements.
• The detailed alignment strategy ensures reliable performance for diverse nanostructure applications.