Higher order off-resonat optical processes for homogeneous and inhomogeneous broadening of liquids

研究了分子系统在一系列非共振飞秒激光脉冲作用下凝聚态的非线性光学响应，研究了液体的非均匀展宽和振动模的非谐性。利用路径积分技术，导出了非简谐系统五阶响应函数的解析表达式。应用这个方程，我们研究了非谐性和非均匀性之间的相互作用。我们还推导了位移非谐系统的五阶响应函数，并将其应用于研究光子回波、泵浦-探测实验，以及最近发展起来的用于检测势的弱非谐性的五阶实验。利用量子福克-普朗克方程，我们研究了Morse势系统的高阶光学过程。该Fokker-Planck方程可以处理高斯白噪声浴或高斯马尔可夫噪声浴中具有任意位势的分子系统。We…此外，还给出了用方程计算三阶和五阶响应函数的方法，这些函数等价于分子坐标的二阶和三阶关联函数。运动方法的方法。假定铯二聚体的势面由Morse势描述，极化率与线性和非线性坐标相关，我们计算了不同温度和热浴耦合时的三阶和五阶响应函数。通过绘制五阶光谱所涉及的两个时间演化周期，我们得到了信号的二维轮廓。这些2D轮廓对于势和极化率的形状是敏感的，甚至对于强衰减情况也是如此，并且依赖于温度。这表明，在不同温度下进行的五阶二维光谱允许我们获得电势和极化率的信息。我们还给出了多态系统的Fokker-Planck方程，并应用于位移Morse振子系统。并对其光学斯塔克效应进行了观察和讨论。较少

The nonlinear optical response of a molecular system in the condensed phase subjected to a series of off-resonant femtosecond laser pulses has been studied to investigate inhomogeneous broadening of liquid states and anharmonicity of vibrational modes. We have derived analytical expressions of the 5th order response function for an anharmonic system using path-integral techniques. Applying this equation, we have studied the interplay between anharmonicity and inhomogeneity. The fifth-order response function for a displaced anharmonic system has been also derived and applied to study photon echo, pump-probe experiments and newly developed the fifth-order experiment which is designed to detect weak anharmonicity of potentials.Using a quantum Fokker-Planck equation, we have studied higher-order optical processes of Morse potential systems. This Fokker-Planck equation can treat a molecular system with any shape of potential coupled to a Gaussian-white or a Gaussian Markovian noise-bath. We … More have presented a procedure to calculate the third-and fifth-order response functions, which are equivalent to the second-and third-order correlation functions of the molecular coordinate, by way of the eq. of motion approach. Assuming the potential surface of a Cesium dimer, which is modeled by the Morse potential, and the linear and nonlinear coordinate dependence of the polarizability, we calculated the third-and fifth-order response functions for various temperatures and heat-bath couplings. By plotting two time-evolution period involved in the fifth-order spectroscopy, we obtained the two-dimensional profiles of the signals. These 2D profiles are sensitive for a shape of potential and polarizability, even for a strong damping case, and depend on the temperature. This indicates that fifth-order two-dimensional spectroscopy carried out for a different temperature allows us to access information of the potential and the polarizability. We have also presented the Fokker-Planck equation for multi-state systems and applied to the displaced Morse oscillators system. Optical Stark effects of it was observed and discussed. Less