摘要
We theoretically investigated the properties of the high-order harmonic generation from an argon atom by bichromatic counter-rotating circularly polarized(BCCP)laser field.The harmonic emission processes have been illustrated by numerically solving the two-dimensional time-dependent Schr¨odinger equation of an atom in intense laser fields.It is found that with the decrease of the right-circularly polarized laser wavelength,the harmonic spectra are gradually splitting and the harmonic orders move towards the higher frequency.Meanwhile,the integer and semi-integer harmonic emission will be generated when the frequency ratios of right-and left-circularly polarized lasers are semi-integer.The emission mechanism of the semi-integer-order harmonics has been investigated by using the rules of photon absorption and emission.
基金
Project supported by the National Natural Science Foundation of China(Grant Nos.61575077 and 11904122)
the Natural Science Foundation of Jilin Province of China(Grant No.20180101225JC)
the China Postdoctoral Science Foundation(Grant Nos.2018M641766 and 2019T120232).
