Using one-dimensional semiconductor Bloch equations,we investigate the multiband dynamics of electrons in a cutoff extension scheme employing an infrared pulse with additional UV injection.An extended three-step model is firstly validated to play a dominant role in emitting harmonics in the second plateau.Surprisingly,further analysis employing the acceleration theorem shows that,though harmonics in both the primary and secondary present positive and negative chirps,the positive(negative) chirp in the first region is related to the so-called short(long) trajectory,while that in the second region is emitted through ’general’ trajectory,where electrons tunneling earlier and recombining earlier contribute significantly.The novel characteristics deepen the understanding of high harmonic generation in solids and may have great significance in attosecond science and reconstruction of band dispersion beyond the band edge.
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机译：A 22.7- to 44.2-GHz Darlington dual-injection injection-locked frequency tripler with 35dBc harmonic rejection for multiband 5G communication systems
机译：Grouphyphen;velocityhyphen;matched secondhyphen;harmonic generation: An efficient scheme for femtosecond ultraviolet pulse generation in periodically domainhyphen;inverted bgr;hyphen;BaB2O4
