原子与分子物理学报
原子與分子物理學報
원자여분자물이학보
Journal of Atomic and Molecular Physics
2015年
5期
829-835
,共7页
非线性光学%Maxwell-Bloch方程%飞秒脉冲%面积定理%两色脉冲
非線性光學%Maxwell-Bloch方程%飛秒脈遲%麵積定理%兩色脈遲
비선성광학%Maxwell-Bloch방정%비초맥충%면적정리%량색맥충
Nonlinear optics%Maxwell-Bloch equations%Femtosecond pulses%Area theorem%Two-color pulse
在不采用旋波近似和慢变幅近似的条件下,通过采用时域有限差分法和预估矫正法数值求解Maxwell-Bloch方程,模拟了飞秒激光脉冲在V型三能级有机分子介质中的传播过程,研究了介质密度对单色脉冲共振传播的影响以及两色飞秒脉冲在该分子体系中的传播情况。有机分子的电子结构和电偶极矩是在密度泛函理论水平上利用从头计算方法得到的。研究结果表明,介质密度对脉冲演化产生较大的影响,随介质密度的增大,非线性效应增强,面积定理逐渐失效;两色脉冲的相对强度及初始相位对各能级的粒子数分布有很大的影响。
在不採用鏇波近似和慢變幅近似的條件下,通過採用時域有限差分法和預估矯正法數值求解Maxwell-Bloch方程,模擬瞭飛秒激光脈遲在V型三能級有機分子介質中的傳播過程,研究瞭介質密度對單色脈遲共振傳播的影響以及兩色飛秒脈遲在該分子體繫中的傳播情況。有機分子的電子結構和電偶極矩是在密度汎函理論水平上利用從頭計算方法得到的。研究結果錶明,介質密度對脈遲縯化產生較大的影響,隨介質密度的增大,非線性效應增彊,麵積定理逐漸失效;兩色脈遲的相對彊度及初始相位對各能級的粒子數分佈有很大的影響。
재불채용선파근사화만변폭근사적조건하,통과채용시역유한차분법화예고교정법수치구해Maxwell-Bloch방정,모의료비초격광맥충재V형삼능급유궤분자개질중적전파과정,연구료개질밀도대단색맥충공진전파적영향이급량색비초맥충재해분자체계중적전파정황。유궤분자적전자결구화전우겁구시재밀도범함이론수평상이용종두계산방법득도적。연구결과표명,개질밀도대맥충연화산생교대적영향,수개질밀도적증대,비선성효응증강,면적정리축점실효;량색맥충적상대강도급초시상위대각능급적입자수분포유흔대적영향。
We simulate the propagation of the femtosecond laser pulses through the V-type three-level organic molecular medium by numerically resolving Maxwell-Bloch equations using finite-difference time-domain and iterative predictor-corrector technique beyond rotating -wave approximation and slowly varying envelope ap-proximation. The effect of the molecular density on the pulse resonant propagation and the dynamics of two-col-or femtosecond pulses are studied. The electronic structure and dipole moments of the organic molecule are com-puted using the ab initio method at the level of density functional theory. The results show that the concentration of the sample has an obvious effect on the evolution of the pulse. Larger concentration results in stronger nonlin-ear effect, and area theorem becomes invalid as the value of molecular density increases; The relative intensity and the initial phase of two-color pulses have great impact on the population of the levels.