Thermal imaging of nanostructures by quantitative optical phase analysis

Area of Science:

• Nanophotonics
• Optical Microscopy
• Thermal Analysis

Background:

• Accurate characterization of heat generation in nanostructures is crucial for understanding their optical and thermal properties.
• Existing methods may lack the comprehensive quantitative analysis required for nanoscale thermal phenomena.

Purpose of the Study:

• To introduce a novel optical microscopy technique for comprehensive and quantitative characterization of heat generation from nanostructures.
• To enable mapping of temperature distribution, heat power density, and retrieval of absorption cross-section.

Main Methods:

• The technique measures thermal-induced refractive index variations in the surrounding medium.
• It utilizes a standard CCD camera combined with a modified Hartmann diffraction grating.
• The method is adaptable to conventional microscopes with broadband illumination.

Main Results:

• Demonstrated the technique's efficacy on gold nanoparticles under plasmonic resonance.
• Achieved diffraction-limited spatial resolution.
• Capable of detecting temperature variations below 1 Kelvin.

Conclusions:

• The developed optical microscopy technique offers a straightforward and quantitative approach to study nanoscale heat generation.
• It provides valuable insights into the thermal behavior of nanostructures, particularly in plasmonics.
• This method enhances the understanding of light-matter interactions at the nanoscale.