Plasmonic Heterodyne Spectrometry for Resolving the Spectral Signatures of Ammonia over a 1-5 THz Frequency Range

TL;DR

This paper introduces a plasmonic heterodyne terahertz spectrometry platform capable of resolving narrow spectral signatures of gases like ammonia over a broad 1-5 THz frequency range, surpassing traditional limitations.

Contribution

The work presents a novel plasmonic photomixing-based heterodyne spectrometer that broadens the tunable frequency range for gas spectral analysis.

Findings

Successfully resolved ammonia spectral signatures from 1-5 THz.

Demonstrated broad tunability surpassing conventional spectrometers.

Enabled high-resolution gas spectroscopy over a wide bandwidth.

Abstract

We present a heterodyne terahertz spectrometry platform based on plasmonic photomixing, which enables the resolution of narrow spectral signatures of gases over a broad terahertz frequency range. This plasmonic heterodyne spectrometer replaces the terahertz mixer and local oscillator of conventional heterodyne spectrometers with a plasmonic photomixer and a heterodyning optical pump beam, respectively. The heterodyning optical pump beam is formed by two continuous-wave, wavelength-tunable lasers with a broadly tunable terahertz beat frequency. This broadly tunable terahertz beat frequency enables spectrometry over a broad bandwidth, which is not restricted by the bandwidth limitations of conventional terahertz mixers and local oscillators. We use this plasmonic heterodyne spectrometry platform to resolve the spectral signatures of ammonia over a 1-5 THz frequency range.