Enhanced terahertz radiation from an elliptical-beam-illuminated sawtooth photoconductive antenna: design and numerical analysis

TL;DR

This paper presents a novel sawtooth-structured elliptical-beam-illuminated photoconductive antenna that significantly enhances terahertz radiation, demonstrated through numerical simulations showing up to double the output compared to conventional designs.

Contribution

The paper introduces a new antenna design with sawtooth electrodes and elliptical laser illumination, leading to increased terahertz radiation efficiency validated by full-wave numerical analysis.

Findings

1. Achieves 1.4 times enhancement in THz radiation over conventional PCA.

2. Potential to double THz output with higher laser power.

3. Uses full-wave FDTD simulation for performance prediction.

Abstract

The enhanced terahertz radiation from a new photoconductive antenna (PCA) has been predicted by numerical simulation. Different from the conventional PCA, the proposed PCA has electrodes with sawtooth structures on the edge, which will introduce stronger localized bias field than common electrode (e.g. strip-line structure). In addition, the elliptical beam of the laser source is used to illuminate the sawtooth structure of the PCA, so that the effective region of the terahertz excitation is enlarged and higher laser power can be applied before saturation effect occurs. The design of the proposed PCA is presented, and its performance is predicated by numerical analysis based on the full-wave finite-difference-time-domain method. The simulated result shows that, comparing with a conventional PCA, the proposed PCA achieves $1.4$ times enhancement of the THz radiation field(i.e. peak of the time-domain THz pulse) at the same condition. Further enhancement as high as $2$ times can be achieved when considering the upper limit of the power density of the incoming laser beam.