Circularly polarized harmonic generation by intense bicircular laser pulses: Electron recollision dynamics and frequency dependent helicity
Numerical solutions of time-dependent Schrdinger equations for one and two electron cyclic molecules Hnq+ exposed to intense bichromatic circularly polarized laser pulses of frequencies w1 and ω2, such that ω1/ω2 =n1/n(integer) produce circularly polarized high order harmonics with a cut-off recollision maximum energy at and greater than the linear polarization law (in atomic units) Nmω1 = Ip + 3.17Up, where Ip is the ionization potential and Up = (2E0)2 4ω2 is the ponderomotive energy defined by the field E0 (intensity I = cE02/8π) from each pulse and mean frequency ω = (ω1 + ω2) 2 . An electron recollision model in a rotating frame at rotating frequency δ ω = (ω1 -ω2) 2 predicts this simple result as a result of recollision dynamics in a combination of bichromatic circularly polarized pulses. The harmonic helicities and their intensities are shown to depend on compatible symmetries of the net pulse electric fields with that of the molecules.
Publication Source (Journal or Book title)
Journal of Physics B: Atomic, Molecular and Optical Physics
Bandrauk, A., Mauger, F., & Yuan, K. (2016). Circularly polarized harmonic generation by intense bicircular laser pulses: Electron recollision dynamics and frequency dependent helicity. Journal of Physics B: Atomic, Molecular and Optical Physics, 49 (23) https://doi.org/10.1088/0953-4075/49/23/23LT01