单周期脉冲、透明导电氧化物、光学非线性、量子相干性、热化效应
Origin, strength, and speed of the nonlinear optical response of transparent conducting oxides to single-cycle optical pulses
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中文总结 AI 辅助
本研究基于密度矩阵框架，通过第一性原理计算探究纳米尺度透明导电氧化物受强极短脉冲激发的非线性光学响应，发现强热非线性及电子-电子热化在几飞秒内发生，为高次谐波测量解读提供支撑。
中文摘要 AI 辅助
我们基于密度矩阵框架，对纳米尺度下透明导电氧化物受强极短脉冲激发产生的非线性光学响应开展第一性原理研究。我们发现了强度为O(1)的强热非线性，其伴随受激发射与激发态吸收，产生带有量子相干振荡的累积介电常数变化。此外，对远非平衡条件的严格计算表明，电子-电子热化在几飞秒内发生，这为高次谐波产生测量的解读提供了支持，且与费米液体理论的推广结论一致。
英文摘要
We present a first-principles study of the nonlinear optical response of transparent conducting oxides at the nanoscale due to excitation by intense, extremely short pulses based on a density matrix framework. We identify a strong ($O(1)$) thermal nonlinearity, which is complemented with stimulated emission and excited-state absorption; it yields a cumulative permittivity change decorated by quantum coherent oscillations. Further, rigorous calculations under far-from-equilibrium conditions show that electron-electron thermalization occurs within a few femtoseconds, supporting interpretations of high-harmonic generation measurements and in agreement with a generalization of Fermi liquid theory.
