Terahertz radiation due to random grating coupled surface plasmon polaritons

TL;DR

This paper demonstrates efficient terahertz radiation from InN semiconductors with random surface defects that couple surface plasmon polaritons to THz emission, revealing spectral and power dependence characteristics.

Contribution

It introduces a novel mechanism of THz emission via random grating-induced plasmon coupling in InN, linking structural factors to emission spectra and power behavior.

Findings

THz emission occurs in the 2-6 THz range.

Emission intensity shows super-linear power dependence.

Spectral shape correlates with the structural factor of the random grating.

Abstract

We report on terahertz (THz) radiation under electrical pumping from a degenerate semiconductor possessing an electron accumulation layer. In InN, the random grating formed by topographical defects provides high-efficiency coupling of surface plasmon polaritons supported by the accumulation layer to the THz emission. The principal emission band occupies the 2-6 THz spectral range. We establish a link between the shape of emission spectra and the structural factor of the random grating and show that the change of slope of power dependencies is characteristic for temperature-dependent plasmonic mechanisms. The super-linear rise of a THz emission intensity on applied electric power provides advantage of such materials in emission yield.