Development of Various Two-Dimensional Vibrational Spectroscopy and Its Application for Practical Use

利用持续时间为55 fs、能量大于1 μJ/脉冲的红外短脉冲，建立了三阶非线性光谱学，并将其应用于凝聚态的振动动力学。实例包括三脉冲光子回波法、波长分辨三脉冲光子回波法和波长分辨瞬态光栅法。在这些方法中，我们可以将信号绘制成多维坐标（如延迟时间和频率）的函数。特别是波长分辨三脉冲光子回波法是二维核磁共振的振动模拟。我们将这些方法应用于几种凝聚相的振动模式，获得了跃迁频率波动的时间相关函数、振动激发态寿命、重定向时间和非谐性。例如：OCN^和SCN^-in甲醇的反对称拉伸模式，Fe(CN)_6^<4->的反对称CN…More拉伸模式，配位到红卟啉的CO拉伸模式，反对称- n =C= n拉伸模式，以及水在反胶团中的OH拉伸模式。在实际应用中需要克服的一个问题是获得非常稳定的红外脉冲。起初，我们认为红外短脉冲应该有足够高的能量，但我们发现，而不是射击对射击脉冲的稳定性比高能量更重要。目前的系统采用超荧光进行光参量产生，这种方法容易引入脉冲的不稳定性。因此，我们构建了一个新的系统，使用白光进行OPG，并设置差频混频装置产生红外脉冲。我们在近红外区域获得了1.7 ~ 2.4 mm的空闲脉冲，在近红外区域获得了1.1 ~ 1.5 mm的信号脉冲，在中红外区域获得了3.0 ~ 5.0 mm的红外脉冲。中红外脉冲的射击对射击稳定性约为0.3%，这几乎是有史以来最好的性能记录。少

By using a infrared short pulse with a duration of 55 fs and energy more than 1 μJ/pulse, which is the shortest IR pulse with a high energy, we have developed third order optical nonlinear spectroscopy and applied to vibrational dynamics in condensed phases. The examples are three-pulse photon echo method, wavelength-resolved three-pulse photon echo method, and wavelength-resolved transient grating method. In these methods we can plot a signal as a function of multi-dimensional coordinates such as delay time and frequency. Especially, wavelength-resolved three-pulse photon echo method is a vibrational analogue of two-dimensional NMR. We applied these methods to several vibrational modes in condensed phases to obtain, for example, the time-correlation function of the transition frequency fluctuation, lifetime of the vibrational excited state, reorientational time, and anharmonicity. The examples are the anti-symmetric stretching modes of OCN^-and SCN^-in methanol, the anti-symmetric CN … More stretching mode of Fe(CN)_6^<4->, the CO stretching mode of coordinated to Ruporphyryine, anti-symmetric -N=C=N-stretching mode, and the OH stretching mode of water in a reverse micelle. One of the problems to be overcome for practical use is to obtain very stable IR pulse. At first, we thought that IR short pulse should have an enough high energy, but we found that rather than that shot-to-shot stability of the pulse is more important that the high energy. The present system uses superfluorescence for optical parametric generation (OPG), and this method easily introduces un-stable nature in the pulse. Therefore, we have constructed a new system which uses white light for OPG, and difference frequency mixing set up to generate IR pulses. We have obtained idler pulses in the near IR region from 1.7 to 2.4 mm, signal pulses in the near IR region from 1.1 to 1.5 mm, and IR pulse in the mid-IR region from 3.0 to 5.0 mm. A shot-to-shot stability of the mid IR pulse is about 0.3%, which is almost the best performance ever recorded. Less