Helicity of harmonic generation and attosecond polarization with bichromatic circularly polarized laser fields

Zhang Jun^{1, 2}, Qi Tong², Pan Xue-Fei², Guo Jing², Zhu Kai-Guang^{1, †}, Liu Xue-Shen^2,

High-order harmonic spectra of helium atom with the intensity ratio (a) γ ′ E = 1.0 and (b) γ ′ E = 2.0 . The other laser parameters are the same as those in Fig. 2. The intensity ratios of the adjacent harmonic orders ( H 3 N + 1 / H 3 N + 2 ) are labeled with red and blue numbers, respectively.