Polarization-sensitive cathodoluminescence Fourier microscopy.

Area of Science:

• Nanophotonics and Plasmonics
• Optical Spectroscopy
• Materials Science

Background:

• Understanding emission polarization is crucial for sub-wavelength structures like optical nanoantennas.
• Angle-resolved cathodoluminescence imaging spectroscopy (ARCIS) is an established technique for studying far-field properties.
• Previous ARCIS methods lacked polarization-sensitive detection capabilities.

Purpose of the Study:

• To extend ARCIS with polarization-sensitive angular detection for analyzing nanostructures.
• To experimentally validate the enhanced ARCIS technique using known dipolar emitters.
• To reconstruct and analyze emission polarization to infer dipole moment orientation.

Main Methods:

• Utilized a 30 keV electron beam for excitation.
• Implemented polarization-sensitive angular detection with ARCIS.
• Collected light emission using an aluminum half paraboloid mirror and accounted for its optical effects.
• Introduced a slit in the beam path to enhance polarization contrast.

Main Results:

• Achieved excellent agreement between experimental data and theoretical predictions for known orthogonal dipolar emitters.
• Successfully probed emission polarization properties of an unstructured gold surface and a ridge nanoantenna.
• Demonstrated the ability to reconstruct emission polarization from experimental data.
• Showcased inference of induced dipole moment orientation from reconstructed field patterns.

Conclusions:

• The enhanced ARCIS technique with polarization sensitivity is effective for detailed analysis of photonic nanostructures.
• This method provides insights into physical properties and aids in optimizing nanostructure applications.
• The technique's capabilities, including polarization sensitivity and high resolution, are valuable for advanced photonic research.