UC Irvine

The investigation we present here of SPP driven field emission, after propagation to a probe tip axis, leads to two firm conclusions. First, we have demonstrated nonlocal electron emission into vacuum driven by an SPP coupled to a surface after geometric focusing. Emitted electrons were measured as a current either using a weak (emission rate independent) collecting bias or with a strong DC voltage whose apex focused local field contributes to the work function suppression of the SPP driven field emission. Second, we demonstrate a number of informative effects of this emission behavior through comparative studies of material, applied voltage ranges, and a fully optimized and controlled surface geometry. The most important of these findings were thermal effects and local damage for this unique case of emission from sites far from incident radiation. While these observations demonstrate efficient coupling to SPPs, they underscore the limitations of local field strength attainable with propagating modes.