This technique, also known as wavelength and angle-resolved cathodoluminescence (WARCL), combines “conventional” angle-resolved CL imaging with hyperspectral CL imaging. Energy-momentum imaging approach opens up new ways for studying optical properties of (nano)materials in wavelength/energy and angle/momentum space in great detail.
This technique originates from angle-resolved cathodoluminescence, which established itself as a powerful tool for quantifying directionality in (nano)antennas, performing multipolar decomposition of the emission, and measuring modal dispersion amongst others. Wavelength and angle-resolved CL, on the other hand, can be used to image dispersive materials and to probe band structure in (quasi)periodic systems.
The note explains the possibilities of lens-scanning energy-momentum (LSEK) applied to a silicon-on-insulator (SOI) substrate and aluminium elliptical plasmonic bullseye antenna. The acquired maps show that the directionality and dispersion of the materials can be tracked through wavelength and angular space. The measurements were done with the SPARC cathodoluminescence detector.