Performing Spectroscopy on Plasmonic Nanoparticles with Transmission-Based Nomarski-Type Differential Interference...

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Differential interference contrast (DIC) microscopy is widely used for imaging microscale objects.
• Single-particle spectroscopy requires precise sample preparation and imaging techniques.
• Plasmonic nanoparticles exhibit unique optical properties crucial for various applications.

Purpose of the Study:

• To provide a detailed protocol for preparing plasmonic nanoparticle samples for single-particle spectroscopy.
• To demonstrate the application of DIC microscopy in conjunction with spectroscopy for nanoparticle analysis.
• To establish a repeatable method for characterizing nanoparticle orientation and optical properties.

Main Methods:

• Etching landmarks onto the substrate for sample navigation and tracking.
• Thorough cleaning of the substrate to remove debris and contaminants.
• Microscope optical path alignment using Kohler Illumination.
• Sample rotation to optimize imaging of orientation-dependent optical properties.
• Utilizing DIC microscopy's polarization fields to reveal nanoparticle orientation.
• Careful data acquisition and analysis, including contrast and intensity data representation.

Main Results:

• Successful preparation of plasmonic nanoparticle samples for spectroscopy.
• Demonstration of repeatable spectroscopy experiments using DIC microscopy.
• Characterization of spherical and rod-shaped gold nanoparticles.
• Correlation of DIC contrast patterns with nanoparticle orientation.

Conclusions:

• The presented protocol enables reliable single-particle spectroscopy of plasmonic nanoparticles using DIC microscopy.
• DIC microscopy offers a valuable method for determining nanoparticle orientation based on optical properties.
• This technique facilitates detailed characterization of nanoparticles for advanced research and applications.