Nanoscale optical tomography with cathodoluminescence spectroscopy

Area of Science:

• Materials Science
• Nanotechnology
• Optics

Background:

• Tomography is crucial for 3D imaging but optical methods face diffraction limits.
• Existing techniques struggle to resolve nanoscale optical properties in three dimensions.

Purpose of the Study:

• To introduce cathodoluminescence spectroscopic tomography (CST) for high-resolution 3D optical property mapping.
• To overcome diffraction limitations in nanoscale optical tomography.

Main Methods:

• Acquire 2D cathodoluminescence maps of nanostructures at multiple orientations.
• Utilize filtered back-projection for 3D tomographic reconstruction.
• Correlate experimental signals with radiative local density of optical states.

Main Results:

• Achieved nanometre-scale spatial and spectral resolution in 3D.
• Successfully mapped 3D cathodoluminescence distributions in visible and near-infrared wavelengths.
• Visualized light-matter interactions in a 3D metal-dielectric nanoresonator.

Conclusions:

• CST enables unprecedented 3D nanoscale visualization of optical properties.
• The technique reveals contributions from material luminescence and eigenmode decay.
• Demonstrated CST's potential for characterizing complex nanophotonic devices.