物理学报2025，Vol.74Issue(3)：45-55,11.DOI:10.7498/aps.74.20241400
飞秒激光诱导分子准直相干性的度量分析
Measurement analysis of coherence in femtosecond laser-induced molecular alignment
摘要
Abstract
Femtosecond laser-induced excitation of molecular rotational states can lead to phenomena such as alignment and orientation,which fundamentally stem from the coherence between the induced rotational states.In recent years,the quantitative study of coherence in the field of quantum information has received widespread attention.Different kinds of coherence measures have been proposed and investigated.In this work,the quantitative correlation is investigated in detail between the intrinsic coherence measurement and the degree of molecular alignment induced by femtosecond laser pulses at finite temperatures.By examining the molecular alignment induced by ultrafast non-resonant laser pulses,a quantitative relationship is established between the l1 norm coherence measure Cl1(ρ)and the alignment amplitude D<cos2 θ>.Here,Cl1(ρ)represents the sum of the absolute values of all off-diagonal elements of the density matrix ρ,D<cos2 θ>represents the difference between the maximum alignment and the minimum alignment.A quadratic relationship Cl1=(a+bε20)× D<cos2 θ>between the the l1 norm coherence measure and D<cos2 θ>with respect to the electric field intensityε0 is obtained.This relationship is validated through numerical simulations of the CO molecule,and the ratio coefficients a and b for different temperatures are obtained.Furthermore,a mapping relationship between this ratio and the pulse intensity area is established.The findings of this study provide an alternative method for experimentally detecting the coherence measure within femtosecond laser-excited rotational systems,thereby extending the potential applicability of molecular rotational states to the study of the coherence measure in the field of quantum resources.This will facilitate the interdisciplinary integration of ultrafast strong-field physics and quantum information.关键词
相干性/分子准直/转动动力学/超快脉冲Key words
coherence/molecular alignment/rotational dynamics/ultrafast pulses引用本文复制引用
廉振中,洪倩倩,贾利娟,孟建桥,束传存..飞秒激光诱导分子准直相干性的度量分析[J].物理学报,2025,74(3):45-55,11.基金项目
国家重点研发计划(批准号:2022YFA1604204)、国家自然科学基金(批准号:12274470,12304311)和湖南省杰出青年自然科学基金(批准号:2022JJ10070)资助的课题. Project supported by the National Key R & D Program of China(Grant No.2022YFA1604204),the National Natural Science Foundation of China(Grant Nos.12274470,12304311),and the Natural Science Foundation of Hunan Province for Distinguished Young Scholars,China(Grant No.2022JJ10070). （批准号:2022YFA1604204）
