Near-field Electrical Detection of Optical Plasmons and Single Plasmon Sources

TL;DR

This paper introduces a novel all-electrical near-field detection method for surface plasmons, enabling efficient, nanoscale optical sensing and advancing the development of integrated plasmonic nanocircuits.

Contribution

It presents a new near-field coupling technique for electrical detection of surface plasmons, achieving high efficiency and enabling dark optoplasmonic nanocircuits.

Findings

Nanoscale, highly efficient plasmon detection (0.1 electrons per plasmon)

Signal amplification via plasmonic gating (up to 50 electrons per plasmon)

Detection of emission from a single quantum dot coupled to a plasmon waveguide

Abstract

Photonic circuits can be much faster than their electronic counterparts, but they are difficult to miniaturize below the optical wavelength scale. Nanoscale photonic circuits based on surface plasmon polaritons (SPs) are a promising solution to this problem because they can localize light below the diffraction limit. However, there is a general tradeoff between the localization of an SP and the efficiency with which it can be detected with conventional far-field optics. Here we describe a new all-electrical SP detection technique based on the near-field coupling between guided plasmons and a nanowire field-effect transistor. We use the technique to electrically detect the plasmon emission from an individual colloidal quantum dot coupled to an SP waveguide. Our detectors are both nanoscale and highly efficient (0.1 electrons/plasmon), and a plasmonic gating effect can be used to amplify the signal even higher (up to 50 electrons/plasmon). These results enable new on-chip optical sensing applications and are a key step towards "dark" optoplasmonic nanocircuits in which SPs can be generated, manipulated, and detected without involving far-field radiation.