Surface plasmon waveguide Schottky detector

Abstract

A surface plasmon polariton detector is demonstrated at infra-red wavelengths. The device consists of a metal stripe on silicon forming a Schottky contact thereon and supporting surface a plasmon polariton mode that is strongly confined and localised to the metal-semiconductor interface. Detection of optical radiation below the bandgap of silicon (at infrared wavelengths) occurs through internal photoemission. Responsivities of 0.38 and 1.04 mA/W were measured via end-fire coupling to a tapered optical fibre, at room temperature and at a wavelength of 1280 nm, for gold and aluminium stripes on n-type silicon, respectively. The device can be integrated with other structures used in nano-plasmonics, nano-photonics or silicon-based photonics, and it holds promise for short-reach optical interconnects and power monitoring applications.