Open AccessCharacterization of laser-induced air plasmas by third harmonic generation
Author(s) -
Cristina Rodríguez,
Zhanliang Sun,
Zhenwei Wang,
Wolfgang Rudolph
Publication year - 2011
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.19.016115
Subject(s) - plasma , femtosecond , laser , optics , electron density , high harmonic generation , materials science , atomic physics , electron , plasma diagnostics , range (aeronautics) , signal (programming language) , physics , quantum mechanics , computer science , composite material , programming language
Third harmonic generation by a weak femtosecond probe pulse intersecting a pump laser-induced plasma in air is investigated and a general model is developed to describe such signal, applicable to a wide range of focusing and plasma conditions. The effect of the surrounding air on the generated signal is discussed. The third-order nonlinear susceptibility of an air plasma with electron density N(e) is determined to be χ(p)((3)) = χ(a)((3)) + γ(p)N(e) with γ(p) = 2 ± 1 × 10(-49) m(5) V(-2) and χ(a)((3)) being the third-order susceptibility in air. Lateral scans of the probe through the plasma are used to determine electron density profiles and the effect of focusing and phase mismatch is discussed.