Investigation On The Fluorescence Dynamics Of DCM And R590 Dyes

As one of the most successful and extensive use laser light source until now, the dye lasers have made great contribution to basic physics, chemistry, biology and many other areas. Compared with other laser mediums, laser dye has a really wide tunable spectrum width, and could output high power, short duration pulses.What's more, a well controllability of absorb and gain could be achieved. With a further development of tunable laser technology, how to improve the luminous efficiency of the dyes is significant.In this thesis, we study on the fluorescence dynamics of several kinds of dyes by steady-state fluorescence spectrum and time-resolved spectroscopy. Fluorescence dynamics means the transfer and relaxation process of basic carriers that influence the fluorescence process. Through steady-state fluorescence we could deduce some basic information of the fluorescence dynamics. But direct study of concrete transient process is not available, so we need to rely on time-resolved spectroscopy. Through years of development, time-resolved spectroscopy points us to track the transient phenomenon and the ultrafast relaxation process in real time. For instance, measuring the level lifetime, studying mechanisms for chemical and biological reactions, all of these couldn't detect by the traditional spectroscopy. Pump-probe technology, as one of the most common time-resolved spectroscopy, is used extensively in physics, especially in the atomic and molecular physics.There has been some reports on the ultrafast lighting performance of liquid dyes, have proved that the ultrafast energy relaxation process between dye molecules or between dye molecules and solvent molecules has an important influence on its performance. But we have never seen any related researches about co-doped and solid dyes. Our experiments include two parts. At first, fluorescence properties of liquid and solid dyes were researched applying femtosecond pulses, both to co-doped and un-doped dyes, changes have been noticed in co-doped and solid situation. We discussed the influence of solvent polarity and reabsorption on the fluorescence properties. On the other hand, main content of this paper is using femtosecond time-resolved pump-probe technology to measure the material's transient transmission spectrum. Based on the transient transmission spectrum, we analyzed the ultrafast energy relaxation process in different periods after the excitation. And we acquired some information about the levels'lifetime which are related to the emission. We hoped that the thesis's research will help us understand the transfer path of electrons after the molecules of laser dye excited, and be helpful to understand the optical character of dye material and make preparation for further study on how to improve the lighting performance of dye in the future.