On-chip detection of radiation guided by dielectric-loaded plasmonic waveguides

TL;DR

This paper introduces a novel on-chip electrical detection method for radiation guided by dielectric-loaded plasmonic waveguides, enabling rapid characterization of complex plasmonic circuits through photocurrent mapping.

Contribution

The study presents a new approach for electrically detecting guided radiation in dielectric-loaded plasmonic waveguides using perforated gold pads and photocurrent mapping, validated by numerical simulations.

Findings

Photocurrent maps successfully distinguish waveguide structures.

Spectral responses match full wave numerical simulations.

Method can be extended to various plasmonic configurations.

Abstract

We report a novel approach for on-chip electrical detection of the radiation guided by dielectric-loaded surface plasmon polariton waveguides (DLSPPW) and DLSPPW-based components. The detection is realized by fabricating DLSPPW components on the surface of a gold (Au) pad supported by a silicon (Si) substrate supplied with aluminum pads facilitating electrical connections, with the gold pad being perforated in a specific locations below the DLSPPWs in order to allow a portion of the DLSPPW-guided radiation to leak into the Si-substrate, where it is absorbed and electrically detected. We present two-dimensional photocurrent maps obtained when the laser beam is scanning across the gold pad containing the fabricated DLSPPW components that are excited via grating couplers located at the DLSPPW tapered terminations. By comparing photocurrent signals obtained when scanning over a DLSPPW straight waveguide with those related to a DLSPPW racetrack resonator, we first determine the background signal level and then the corrected DLSPPW resonator spectral response, which is found consistent with that obtained from full wave numerical simulations. The approach developed can be extended to other plasmonic waveguide configurations and advantageously used for rapid characterization of complicated plasmonic circuits.