发表机构
Institute for Quantum Information and Matter, California Institute of Technology; Department of Physics, California Institute of Technology; Materials Department, University of California, Santa Barbara; Institute of Physics, Academia Sinica; Department of Chemistry, Emory University（加州理工学院量子信息与物质研究所; 加州理工学院物理系; 加州大学圣塔芭芭拉分校材料系; 中央研究院物理学研究所; 埃默里大学化学系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究在莫特绝缘体La₂CuO₄中实现23阶高次谐波产生，通过时间分辨光谱解析多体过程贡献，揭示光掺杂触发的多体重构可调控非线性光学响应，确立HHG为探测关联电子的灵敏工具。
AI 中文摘要
高次谐波产生（HHG）已成为探测固体中超快电子动力学的有力工具。然而在强关联材料中，电子激发源于多体相互作用而非单粒子能带色散，该领域仍处于起步阶段。本文报道了在典型莫特绝缘体La₂CuO₄中产生的高达23阶的HHG，观察到与驱动场强度无关的4 eV稳健截止，揭示了由哈伯德带定义的本征能量尺度。利用时间分辨高次谐波光谱，我们解析了载流子产生、带内加速和带间复合对非平衡辐射光谱的不同贡献。我们证明光掺杂会在临界激发密度以上触发多体流形的基本重组，该过程会重整化能带曲率并抑制非线性带内电流，从而将多体能带重构的特征直接印记在谐波发射上。这些结果确立了HHG作为探测微妙关联驱动电子重构的灵敏工具，并强调多体相互作用能在非平衡态下实现高度可调的极端非线性光学响应。
英文摘要
High harmonic generation (HHG) has emerged as a powerful probe of ultrafast electron dynamics in solids. However, in strongly correlated materials, where electronic excitations arise from many-body interactions rather than single-particle band dispersion, the field remains in its infancy. Here, we report HHG up to the 23$^{rd}$ order in the prototypical Mott insulator La$_2$CuO$_4$. We observe a robust 4 eV cutoff that is independent of driving field strength, revealing an intrinsic energy scale defined by the Hubbard bands. Using time-resolved high harmonic spectroscopy, we disentangle the distinct contributions of carrier creation, intraband acceleration, and interband recombination to the nonequilibrium radiation spectrum. We demonstrate that photo-doping triggers a fundamental reorganization of the many-body manifolds above a critical excitation density, a process that renormalizes the band curvature and suppresses nonlinear intraband currents, thereby directly imprinting the signature of many-body band reconstruction onto the harmonic emission. These results establish HHG as a sensitive probe of subtle correlation-driven electronic reconstructions and highlight that many-body interactions enable extreme nonlinear optical responses that are highly tunable in nonequilibrium states.
Comments13 pages main text, 4 figures, 32 pages supplementary information
