Photofield electron emission from an optical fiber nanotip

TL;DR

This paper introduces a flexible, fiber-based nanotip electron source that uses laser-induced single-photon photoemission for fast, controllable electron emission, suitable for advanced imaging and quantum applications.

Contribution

It presents a novel fiber optic nanotip design capable of laser-induced photoemission with fast switching, expanding the potential for flexible and addressable electron sources.

Findings

Laser-induced photoemission observed below dark FE threshold

Fast switching times with an upper limit of 1 microsecond

Flexible, back-illuminated nanotip emitters operable in CW and pulsed modes

Abstract

We demonstrate a nanotip electron source based on a graded index multimode silica optical fiber, tapered at one end to a radius of curvature r ~ 50 nm and coated with a thin film of gold. We report observation of laser-induced electron photoemission at tip bias potentials below the onset of dark field emission (FE). Single-photon photofield emission (PFE) is identified as the emission mechanism, which exhibits fast switching times with an upper limit on the order of 1 {\mu}s. The explored fiber optic nanotips are flexible back-illuminated emitters, which can be operated in continuous wave (CW) and pulsed modes using lasers with photon energies in the visible range or higher. The mechanical flexibility of the source can facilitate externally controlled positioning. Multiple, individually addressable, nanotips may be assembled into a bundle for applications such as computational electron ghost imaging.