Electron beam excited non-bridging oxygen hole centers in silica as nanophotonic probes

Electron-beam cathode luminescence spectroscopy is a remarkable method for probing nanophotonic modes with deep sub-diffraction limited resolution. However, its use has been limited to modes which radiate to the far-field where detection occurs. Here, we electrically excited non-bridging oxygen hole centers (NBOHCs) in a silica fiber and collected their fluorescence through the fiber modes [1]. This allows the probing of the mode local density of states, despite the fiber modes being non-radiative. We discuss extensions of the technique and future applications.