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Study of characteristic role of lower lying energy levels in optical relaxation processes

光学弛豫过程中较低能级特征作用的研究

基本信息

批准号：
15540316
负责人：
ITOH Hiroshi
金额：
$ 2.11万
依托单位：
Kagawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

There are many kinds of optical relaxation processes according to the states of crystals, liquids and gasses. These processes are understood as the results of electron-lattice interaction briefly. But, we do not almost know main physical constants to control the optical processes. In that case we only suppose phonon structures affecting the influences to the relaxation processes in condensed matters.Then we have attempted to catch what kinds of phonon making role of activator to relax the excited electron states, in particular, in the system of amorphous matrix such as dye/polyvinylalcohol. On the other hand, four-wave mixing is one of the most versatile and sensitive methods to detect the environmental condition of the probe molecular since it can detect the difference of the order of ueV.At first, we have performed to detect the phase relaxation time T2 under irradiating IR radiation which was monochrolized light tuned to the vibrational energy of OH stretching mode from SiC thermal source by using monochrometor. In this case, sample was sulfurohdamine 640 and PVA as matrix and the sample temperature was 4.2 K. In this experiment, we have not been able to detect the change of T2 when the IR light was on or off. This experiment has been not so complete because the intensity of SiC source was so weak that alignment was very difficult. Now we attempting this experiment.Next, we employed Mira-OPO idler light as an exciting IR light whose wavelength was 2.7um and pulse duration was about 120 fs. In this case, T2 was clearly reduced into the half of it before irradiating idler light. But now we can not understand that this is meaningful micro-thermal effect because sample temperature might have raised simply.Anyway, we are now continuing the more precise experiment.

根据晶体、液体和气体的状态，光学弛豫过程有很多种。这些过程被简单地理解为电子-晶格相互作用的结果。但是，我们几乎不知道控制光学过程的主要物理常数。在这种情况下，我们只假设声子结构对凝聚态物质中的弛豫过程有影响。然后我们试图捕捉什么样的声子发挥激活剂的作用来弛豫激发电子态，特别是在染料/聚乙烯醇等非晶基质体系中。另一方面，四波混频是检测探针分子环境条件最通用和最灵敏的方法之一，因为它可以检测ueV级的差异。首先，我们使用单色仪检测了IR辐射下的相位弛豫时间T2，该IR辐射是单色光调谐到来自SiC热源的OH伸缩模式的振动能量。本例中，样品为磺胺640，PVA为基质，样品温度为4.2 K。在本实验中，我们无法检测到IR灯打开或关闭时T2的变化。这个实验还不是很完整，因为碳化硅源的强度太弱，对齐非常困难。现在我们尝试这个实验。接下来，我们使用 Mira-OPO 闲频光作为激发红外光，其波长为 2.7um，脉冲持续时间约为 120 fs。在这种情况下，T2明显减少到照射闲散光之前的一半。但现在我们不能理解这是有意义的微热效应，因为样品温度可能只是简单地升高。无论如何，我们现在正在继续更精确的实验。