Gate- and Optically Controlled Nonlinear Optical Response in Graphene via Non-Perturbative Ultrafast Carrier Dynamics

Fuente: arXiv
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Main Authors: Lv, Xiaolong, Zhang, Yu, Wei, Yuxuan, Tian, Chuanshan
Format: Preprint
Published: 2026
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author Lv, Xiaolong
Zhang, Yu
Wei, Yuxuan
Tian, Chuanshan
author_facet Lv, Xiaolong
Zhang, Yu
Wei, Yuxuan
Tian, Chuanshan
contents While the Dirac band structure of graphene has established it as a leading platform for ultrafast optoelectronics, its non-perturbative nonlinear response under intense excitation remains poorly understood. Here, we report ultrafast spectral modulation of nonlinear optical signals in graphene. By utilizing a robust suspended-graphene platform that allows for both wide-range electrostatic gating and high optical damage thresholds, we observe dramatic frequency shifts (up to 8 THz) in third-harmonic generation (THG) and sum-frequency generation (SFG) driven by pump-induced nonequilibrium carrier dynamics. The magnitude and even the direction of this spectral shift can be reversibly controlled by the Fermi level and excitation conditions. A quasiequilibrium theoretical framework based on hot-carrier dynamics quantitatively reproduces the measured spectral evolution, elucidating the critical interplay between carrier heating and the Fermi level. These findings establish a universal mechanism for carrier-mediated spectral control, providing a practical route toward high-speed, gatetunable nonlinear photonic architectures.
format Preprint
id arxiv_https___arxiv_org_abs_2604_22321
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Gate- and Optically Controlled Nonlinear Optical Response in Graphene via Non-Perturbative Ultrafast Carrier Dynamics
Lv, Xiaolong
Zhang, Yu
Wei, Yuxuan
Tian, Chuanshan
Optics
While the Dirac band structure of graphene has established it as a leading platform for ultrafast optoelectronics, its non-perturbative nonlinear response under intense excitation remains poorly understood. Here, we report ultrafast spectral modulation of nonlinear optical signals in graphene. By utilizing a robust suspended-graphene platform that allows for both wide-range electrostatic gating and high optical damage thresholds, we observe dramatic frequency shifts (up to 8 THz) in third-harmonic generation (THG) and sum-frequency generation (SFG) driven by pump-induced nonequilibrium carrier dynamics. The magnitude and even the direction of this spectral shift can be reversibly controlled by the Fermi level and excitation conditions. A quasiequilibrium theoretical framework based on hot-carrier dynamics quantitatively reproduces the measured spectral evolution, elucidating the critical interplay between carrier heating and the Fermi level. These findings establish a universal mechanism for carrier-mediated spectral control, providing a practical route toward high-speed, gatetunable nonlinear photonic architectures.
title Gate- and Optically Controlled Nonlinear Optical Response in Graphene via Non-Perturbative Ultrafast Carrier Dynamics
topic Optics
url https://arxiv.org/abs/2604.22321