Two-color laser wavelength effect on intense terahertz generation in air
Li Shufen1, 2, Lu Chenhui3, , Yang Chengshuai2, Yu Yanzhong1, Sun Zhenrong2, Zhang Shian2, 4,
       

(color online) The electron velocities with the laser wavelengths (black squares), 800 nm (red circles), and 1600 nm (green triangles) for the given laser intensity of and pulse duration of τ = 50 fs. The positon of the symbols corresponds to the ionization event, and its value represents the velocities of electron produced in the ionization events.