| In the information age, since the demand of information for people increase sharply, the traditional communication technology has been difficult to meet the growing capacity requirements of communication. The optical communication technology becomes the most important communication technology for its potential bandwidth capacity. However, optical communication system in the current process of converting has some issues, such as a serious cross talk and high power consumption and so on, which lead to the phenomenon of information bottleneck. In order to solve the problems, all-optical switching (AOS) has been paid dramatic attention because of its strong resistance electromagnetic and fast response. In the AOS, the data transfer process from the source node to destination node in the optical domain transfer process is carried out in the optical domain. To be practically useful for AOS, materials should have a large nonlinear refractive index at the operation wavelength, a low linear and nonlinear absorption and an ultrafast response time, together with good physicochemical properties.Our group has done in-depth studies on the third-order nonlinear optical (NLO) materials for AOS applications. The research results exhibits that transition metal 1,3-dithiole-2-thioxo-4,5-dithiolato (DMIT) complex, coordination complexes possess largeÏ€-electron delocalization, charge transfer and high electromigration rate in the systems, so the materials may possess large nonlinear refraction, small linear and nonlinear absorption. They have potential valuable application on AOS devices. Based on the previous work, a continued research work on the exploration some new materials to meet the AOS. Several factors affecting the third-order NLO performance have been also investigated. The main work is as follows:Firstly, according to the demands of AOS and the characteristics of largeÏ€-electron delocalization for DMIT materials, through changing metal ions and cations, several kinds of metal-DMIT coordination complexes (R4N)Au(DMIT)2 (R=C2H5, C3H7, C4H9);((RR'3N)2Mn(DMIT)2(R=C4H9,C3H5å'ŒC6H4-CH3, R'为C4H9, CH3, C6H5), have been synthesized. Among them, the crystal structure and third-order NLO properties of (C4H9)4N)2Mn(DMIT)2 have been first reported.Secondly, the basic physicochemical properties, including thermal, infrared (IR) and linear optical absorption, have been studied thoroughly. The third-order NLO characteristics of Au-, Mn- and Ni-DMIT complexes have been investigated by using Z-scan technique. The NLO parameters, such as second hyperpolarizability, nonlinear refraction coefficient and nonlinear absorption coefficient, have been obtained.Thirdly, the influence factors for the third-order NLO characteristics of materials have been studied and a series of important results have been obtained:the external cations only have very small effects on the third-order NLO characteristics of the DMIT complexes. The main factor for the third-order NLO characteristics is the center metal ion. It is discovered that Au- and Mn-DMIT materials satisfy the requirements of two quality factors for the AOS device (W=n2I0/α0λ, T=βλ/n2 and |W|>>1,|T|<<1).In summary, this paper designed and explored third-order nonlinear optical materials with fast response time through changing the external cations or the central metal ions of dmit organometallic complexes. We obtained several nonlinear optical materials which have potential applications in all-optical switching through the selection of materials. |
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