Cationic Dyes Of Sol-gel Thin Films And Nonlinear Optical Properties

The phenomenon of bad mechanical characteristics, degeneracy and relaxation universally existing in the organic nonlinear optical materials badly limits their application. This defect can be avoided by doping organics into the three-dimensional inorganic networks with stronger mechanical strength and better chemical stability, and which can make features of organics practice better and more sufficiently.Sol-gel method is a very important route to prepare the organic/inorganic (O/I) hybrid materials, which allows to confound organics and inorganic ones in arbitrary proportion at the mild temperature which below or above the room temperature. We can obtain nanometer composite O/I hybrid materials with some features cannot be possessed by the traditional composite materials.By improving the methods such as using a process named Ormosil , the NLO can bond with the inorganics and to be provided with higher polarization rate. Favor of improving nonlinear optical effect, by which the crystallization trend of the organics can be restrained. And the optical diaphaneity and NLO susceptibility and thermal stability of materials are also improved.In this paper, the organic dye with higher nonlinear optical effect such as Cationic Red GTL, Cryptocyanine, Methl Red, Rhodamine 6G are doped into inorganic SiO2 network. The preparing techniques of films to be used as integrated optic-electronic devices interconnection in the optical communication are studied. And through measuring the absorption, the fluorescence spectra and the optical nonlinearity of the materials, the effect of photoelectric performance of composite O/I hybrid materials is discussed. This article is divided into 5 chapters.In the 1st chapter, the progress and current problems of sol-gel method are discussed in detail, and the approach of preparing organic dye gel whit higher nonlinear effect is analyzed and a new method of bonding O/I NLO hybrid materials is introduced, it proves superior to some other methods.In the 2nd chapter, by analyzing the structure, which associate with the nonlinearity of nonlinear organics, we have choose the cationic dye as the host part in the O/I hybrid materials. The cationic dye is a universally commercialized organic dye and their nonlinearities have testified in many practices.In the 3rd chapter, as sol-gel technique possesses many advantages, such as film preparing, we discussed the techniques of the sol-gel films preparing and take Ormosil process, layer numbers, spin velocity, heat-treatment as the important roles in fabricating the film and show how they effect the film. In the end, we studied the basic properties of the film by the spectrum.In the 4th chapter, the optic nonlinearity of gelatinous materials is discussed byusing z-can technology. We also discussed the effect of photoelectric performance of composite O/I hybrid materials, by comparison to the dye in ethanol solution.In the 5th chapter, the conclusion is drawn and the prospect of applying optical nonlinear gelatinous materials is discussed.There are two innovations in our work: (1) selecting the cationic dyes to be doped in the gel will extend their applicability and they can be an important chooses in optic-electronic devices. (2) A theory was brought forward that the organics doped in the network by binding covalently with the inorganics effect the gel linear and nonlinear optic properties, and the effect of dielectric confinement on the doped dye play the same role.