Broadband terahertz emission from two-color femtosecond-laser-induced microplasmas

Illia Thiele (1) , Pedro González de Alaiza Martínez (2) , Rachel Nuter (1) , A Nguyen (2) , L Bergé (2) , Stefan Skupin (3, 1)

1 CELIA - Centre d'Etudes Lasers Intenses et Applications
2 DPTA - Département de Physique Théorique et Appliquée
3 ILM - Institut Lumière Matière [Villeurbanne]

We investigate terahertz emission from two-color fs-laser-induced microplasmas. Under strongest focusing conditions, microplasmas are shown to act as point-sources for broadband terahertz-to-far-infrared radiation, where the emission bandwidth is determined by the plasma density. Semi-analytical modeling allows us to identify scaling laws with respect to important laser parameters. In particular, we find that the optical-to-THz conversion efficiency crucially depends on the focusing conditions. We use this insight to demonstrate by means of Maxwell-consistent 3D simulations, that for only 10-µJ laser energy a conversion efficiency well above 10 −4 can be achieved.

Domaines: Optique [physics.optics]; Physique Atomique [physics.atom-ph]; Physique des plasmas [physics.plasm-ph]

Illia Thiele, Pedro González de Alaiza Martínez, Rachel Nuter, A Nguyen, L Bergé, et al.. Broadband terahertz emission from two-color femtosecond-laser-induced microplasmas . Physical Review A : Atomic, molecular, and optical physics [1990-2015], 2017, 96, pp.053814. ⟨10.1103/PhysRevA.96.053814⟩. ⟨hal-01545465⟩