Ultrafast, surface plasmon-enhanced, au nanorod optical field electron emitter arrays

Abstract

In this work we demonstrate the design, fabrication and characterization of ultrafast, surface-plasmon enhanced Au nanorod photofield emitter arrays. We present a quantitative analysis of charge yield from plasmonic Au nanorod arrays fabricated by high-resolution electron beam lithography and triggered by 35 fs pulses of 800 nm light. We have accurately modeled both the optical field enhancement of Au nanorods in high-density arrays, and electron emission from those nanorods. We have considered the effects of surface plasmon damping induced by metallic interface layers at the substrate/nanorod interface on electron emission. We have identified the peak optical field at which the electron emission mechanism transitions from a 3-photon absorption mechanism to strong-field tunneling emission. Moreover, we have investigated the effects of nanorod array density on nanorod charge yield, including measurement of space-charge effects.