Light Emission Enhancement on Nanostructured Surfaces Quantitatively Evaluated by Cathodoluminescence Coincidence Counting

Quantification of light emission enhancement from materials by optical resonators is an important fundamental issue. Cathodoluminescence (CL) spectroscopy has the potential to analyze the emission properties of materials with nanometer spatial resolution far beyond the diffraction limit of light. However, due to the lack of excitation wavelength selectivity, it is often challenging for CL to discriminately evaluate multiple emission processes in emitter-resonator systems. Especially in cases where the optical resonators can enhance not only the emission but also the excitation of the emitters, quantification of the light emission enhancement independent of the excitation method becomes more complex. Here, we propose an application of Hanbury Brown-Twiss (HBT) interferometry that is sensitive to the excitation efficiency of CL. We used HBT-CL as well as CL spectroscopy to evaluate the light emission of halide perovskites enhanced by plasmonic resonators and found that the enhancement can be quantified as an increase in coincidence counts. The plasmonic resonator caused almost no change in the second-order autocorrelation function, confirming that the effect of the resonator on electron beam excitation was negligible. Our results suggest that HBT-CL is effective for the quantitative evaluation of light emission enhancement in various emitter-resonator systems.