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arXiv 2201.10670cond-mat.mes-hall
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正交极化双色laser场在石墨烯中的高效高次谐波产生

Efficient high-harmonic generation in graphene with two-color laser field at orthogonal polarization

Hamlet K. Avetissian, Garnik F. Mkrtchian, Andreas Knorr

摘要:

研究了由超短线偏振激光脉冲的基波和二次谐波组成的双色辐射场在石墨烯中的高阶混频。结果表明,在正交偏振双色场的情况下,有效地产生了源于带间跃迁的谐波。在这种情况下,所产生的高次谐波比在平行极化情况下获得的高次谐波强两个数量级以上。这与原子和半导体系统形成鲜明对比,在原子和半导体系统中,平行极化的情况更优选。这种增强的物理起源也从三步半经典电子-空穴碰撞模型推导出来,扩展到具有伪相对论能量色散的石墨烯。特别地,我们讨论了在动力学Hartree-Fock近似下多粒子库仑相互作用对HHG过程的影响。我们的分析表明,在所有情况下,我们有一个整体增强的HHG信号相比,由于电子-空穴的相互作用的自由电荷载流子模型。

英文摘要:

High-order frequency mixing in graphene using a two-color radiation field consisting of the fundamental and the second harmonic fields of an ultrashort linearly polarized laser pulse is studied. It is shown that the harmonics originated from the interband transitions are efficiently generated in the case of the orthogonally polarized two-color field. In this case, the generated high-harmonics are stronger than those obtained in the parallel polarization case by more than two orders of magnitude. This is in sharp contrast with the atomic and semiconductor systems, where parallel polarization case is more preferable. The physical origin of this enhancement is also deduced from the three-step semi-classical electron-hole collision model, extended to graphene with pseudo-relativistic energy dispersion. In particular, we discuss the influence of the many particle Coulomb interaction on the HHG process within dynamical Hartree-Fock approximation. Our analysis shows that in all cases we have an overall enhancement of the HHG signal compared with the free-charged carrier model due to the electron-hole attractive interaction.

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