论文标题
在正交极化处具有两色激光场的石墨烯中有效的高谐波产生
Efficient high-harmonic generation in graphene with two-color laser field at orthogonal polarization
论文作者
论文摘要
研究了由两色辐射场在石墨烯中混合的高阶频率混合，该辐射场由超短线性激光脉冲的基本和第二个谐波场组成。结果表明，在正交极化的两色场的情况下，谐波起源于带间跃迁。在这种情况下，产生的高甲基动物比在平行极化情况下获得的高度要高两个以上的数量级要强。这与原子和半导体系统形成鲜明对比，在该系统中，平行极化情况更可取。这种增强的物理起源也是从三步半经典电子孔碰撞模型中推导的，该模型以伪偏爱的能量分散延伸至石墨烯。特别是，我们讨论了许多粒子库仑相互作用对动态hhtree-cock近似中HHG过程的影响。我们的分析表明，在所有情况下，由于电子孔有吸引力的相互作用，我们与自由充电载体模型相比，HHG信号的总体增强。
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.
