Direct imaging of photonic band-edge states in golden Vogel spirals using photoemission electron microscopy

Abstract

Golden Vogel spirals, as deterministic aperiodic structures, support isotropic photonic band gaps and have interesting applications. Localized modes, such as band-edge states, are essential for tailored light–matter interaction. Here we report imaging of such modes using photoemission electron microscopy (PEEM). Tunable ultrashort light pulses excite them in golden Vogel spirals that were fabricated by focused-ion-beam (FIB) milling of an a-Si:H layer. The local near-field leads to electron emission, which is detected spatially resolved. The demonstration of FIB-textured a-Si:H as photonic material and the ability of mode imaging by PEEM offers means to spatiotemporally resolve mode dynamics and to perform nanospectroscopy.