Spectral control of terahertz radiation from inhomogeneous plasma filaments by tailoring two-color laser beams

Terahertz (THz) radiation from an inhomogeneous plasma filament generated by focusing two-color femtosecond laser pulses into argon gas filled in a chamber is investigated experimentally by tailoring the Gaussian pump laser beams with an iris, where broadband THz emission over 10 THz is produced. It is found that the collected far-field THz radiation includes not only coherent but also partial-coherent components of the THz waves, which are emitted from the different parts of the inhomogeneous plasma filament with different plasma densities, contributing correspondingly to the different frequencies of the THz spectrum. Our results suggest that the THz spectrum can be manipulated by controlling the plasma density distribution of the filaments. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

The study investigates Terahertz (THz) radiation generated from an inhomogeneous plasma filament by manipulating the plasma density distribution, which contributes to different frequencies of the THz spectrum. The collected THz radiation includes both coherent and partial-coherent components.