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arXiv · 2306.17346

Enhancement of high-order harmonic generation in graphene by mid-infrared and terahertz fields

Wenwen Mao·Angel Rubio·Shunsuke A. Sato
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Abstract

We theoretically investigate high-order harmonic generation (HHG) in graphene under mid-infrared (MIR) and terahertz (THz) fields based on a quantum master equation. Numerical simulations show that MIR-induced HHG in graphene can be enhanced by a factor of 10 for fifth harmonic and a factor of 25 for seventh harmonic under a THz field with a peak strength of 0.5 MV/cm by optimizing the relative angle between the MIR and THz fields. To identify the origin of this enhancement, we compare the fully dynamical calculations with a simple thermodynamic model and a nonequilibrium population model. The analysis shows that the enhancement of the high-order harmonics mainly results from a coherent coupling between MIR- and THz-induced transitions that goes beyond a simple THz-induced population contribution.

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Wenwen Mao, Angel Rubio, Shunsuke A. Sato. 2023-06-30. Enhancement of high-order harmonic generation in graphene by mid-infrared and terahertz fields. https://arxiv.org/abs/2306.17346

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