Wavelength- and angle-resolved technique for determining the energy-momentum diagram of photonic systems

The photonic band structure of plasmonic and nanophotonic materials and devices can be controlled by physical features much smaller than the optical diffraction limit. We present a methodology to correlate nanoscale structure to the photonic band structure directly using the cathodoluminescence (CL) signal generated by a sample in the scanning electron microscope. Further to conventional electron microscope imaging, we record the wavelength- and angular- distributions of luminescence in a highly- parallelized manner. The result is a wavelength- and angle- resolved data cube, which was transformed to observe the emission intensity in the energy-momentum basis revealing the photonic band structure.