超短脉冲激光在有机分子材料中的动力学过程研究  

Dynamical behavior of ultrashort pulse laserin para-nitroaniline molecules

作　　者：李洪玉[1] 赵珂[1] 潘瑞芹[1] 孙元红[1] 王传奎[1] 

机构地区：[1]山东师范大学物理与电子科学学院,济南250014

出　　处：《物理学报》2005年第5期2072-2078,共7页Acta Physica Sinica

基　　金：国家自然科学基金 (批准号 :10 2 740 44 ) ;山东省优秀中青年科学家奖励基金 (批准号 :0 3BS0 61);中国科学院上海光机所强光光学研究所开放实验室资助的课题 .~~

摘　　要：利用从头计算方法 ,在密度泛函理论上 ,计算了分子的电子结构和电偶极矩 .通过求解麦克斯韦 布洛赫方程 ,研究了超短脉冲激光与硝基苯胺分子材料的相互作用 ,着重分析了分子的固有偶极矩对脉冲激光波形、频谱成分以及分子能级占有率产生的影响 .研究结果表明 ,慢变幅近似和旋波近似不能很好地描述超短脉冲在PNA分子介质中传播 .分子的固有偶极矩进一步使脉冲传播背离面积定理 ,引起了脉冲更快地分裂 .当脉冲激光在PNA分子介质中以电荷转移态的激发能共振传播时 ,脉冲激光频谱中明显地出现了二次谐波成分 ,显示了该分子具有较强的双光子吸收性质 .The electronic structures and dipole moments of para- nitroaniline molecule are calculated by use of density functional theory at ab initio level. We then investigate theoretically the interaction between the ultrashort pulse laser and the para-nitroaniline molecule medium by solving, the full Maxwell-Bloch equations. The effects of permanent dipole moments on the pulse reshaping, the spectrum components, and the evolutions of energy state populations are discussed in detail. The results show that the standing slowly varying envelope and the rotating-wave approximations fail to give a good description for the propagation of an ultrashort pulse in the molecule medium. Furthermore, the dipole moments of the molecule make the propagation deviate from the area theorem further and make the pulse split more quickly. When the pulse with the excitation energy of the charge-transfer state propagates in the para-nitroaniline molecule medium, the second-harmonic spectral component appears obviously and becomes stronger as the propagating distance increases, which displays the high two-photon absorption properties of the molecule.

关 键 词：超短脉冲激光 硝基苯胺分子 麦克斯韦-布洛赫方程 有机分子材料 非线性光学性质 

分 类 号：TN241[电子电信—物理电子学]