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

利用最短、能量大于1μJ/PULSE、脉宽为55fs的红外短脉冲，发展了三阶光学非线性光谱，并应用于凝聚态的振动动力学研究。例如三脉冲光子回波法、波长分辨三脉冲光子回波法和波长分辨瞬变光栅法。在这些方法中，我们可以将信号绘制为多维坐标的函数，例如延迟时间和频率。特别是，波长分辨三脉冲光子回波方法是二维核磁共振的振动模拟方法。我们将这些方法应用于凝聚相中的几个振动模，得到了跃迁频率涨落、振动激发态寿命、重定向时间和非谐性的时间关联函数。例如，OCN^-和SCN^-在甲醇中的反对称伸缩模式，反对称CN…Fe(CN)6^&lt；4-&gt；的较多伸缩模式，配位Ruporryine的CO伸展模式，反对称-N=C=N-伸展模式，以及水在反胶束中的OH伸展模式。在实际应用中需要克服的问题之一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，脉冲的稳定性比高能量更重要。目前的系统采用超荧光产生光参数(OPG)，这种方法容易在脉冲中引入非稳定的性质。因此，我们构建了一种新的系统，它使用白光作为OPG，并建立了差频混频来产生红外脉冲。我们在1.7-2.4 mm的近红外区域获得了较空闲的脉冲，在1.1-1.5 mm的近IR区域获得了信号脉冲，在3.0-5.0 mm的中IR区域获得了IR脉冲。中红外脉冲的点对点稳定度约为0.3%，这几乎是有记录以来最好的性能。较少

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