# Bias field tailored plasmonic nano-electrode for high-power terahertz photonic devices

## TL;DR

This paper introduces a new design for nano-electrodes that improves terahertz devices by focusing on bias field distribution rather than plasmonic effects.

## Contribution

The study reveals that bias field distribution, not plasmonic enhancement, is key to improving THz emitter performance.

## Key findings

- Plasmonic field enhancement has a limited role in nano-structured electrode performance.
- Locally enhanced bias field due to size effects is more important for THz emitters.
- Tailoring bias field distribution improves nano-electrode design for THz devices.

## Abstract

Photoconductive antennas with nano-structured electrodes and which show significantly improved performances have been proposed to satisfy the demand for compact and efficient terahertz (THz) sources. Plasmonic field enhancement was previously considered the dominant mechanism accounting for the improvements in the underlying physics. However, we discovered that the role of plasmonic field enhancement is limited and near-field distribution of bias field should be considered as well. In this paper, we clearly show that the locally enhanced bias field due to the size effect is much more important than the plasmonic enhanced absorption in the nano-structured electrodes for the THz emitters. Consequently, an improved nano-electrode design is presented by tailoring bias field distribution and plasmonic enhancement. Our findings will pave the way for new perspectives in the design and analysis of plasmonic nano-structures for more efficient THz photonic devices.