| Copper-based materials not only show widely application in superconductivity, catalysis and storage technology for their high dielectric constant, but also come to be a research focus in recent years for their excellent nonlinear optical property, especially for film materials. This unusual optical transmittance and good nonlinearlity of cuprate films allow them more attractive in the preparation of nonlinear optical devices. Here, a series of cuprate films were fabricated by high-temperature solid state method, screen-printing technique, RF magnetron sputtering and subsequent sintering and annealing. The facial and cross-sectional micro-structure, sizes of elements, particles distribution and third-order optical nonlinearity of the prepared films were systematically investigated and discussed through various methods,detailed contents are as follows:1. The micro-crystalline Ca2CuO3 glass films in varying thickness have been successfully prepared by high-temperature solid state and screen-printing techniques, and assisted with subsequent co-sintering and polishing process. The changes of Ca2CuO3 phases in the glass films were determined by X-ray powder diffraction meter ?XRD? during the sintering and polishing process. In addition, the surface and cross-section morphology, elements distribution of the samples in different thickness were detailedly analyzed using scanning electron microscopy ?SEM? and X-ray photoelectron spectroscopy ?XPS?. Meanwhile, the third-order nonlinearity of the samples was studied by a single pulse Z-scan technique at the wavelength of 532 nm, pulse duration of 190 fs, energy of 0.1?J and repetition frequency of 20 Hz. The results suggested that 450? sintered Ca2CuO3 glass film own a best nonlinear optical property after polishing for 120 min, which shows reverse saturable absorption and self-defocusing nonlinear refraction behavior, corresponding nonlinear optical susceptibility X?3? was calculated to be 6.1×10-12 esu.2. The CaCuO2/CaCu2O3 thin films were fabricated on the quartz substrates by using RF magnetron sputtering and subsequent annealing.The XRD was carried to determine the phase variation of cuprates films annealed at variable temperature. After that, the surface morphology,configuration of cross-section and elements distribution for as-grown and annealed cuprates films were systematically studied and discussed by using scanning electron microscopy ?SEM?, transmission electron microscopy ?TEM?, and X-ray photoelectron spectroscopy ?XPS?. For further understand the optical property of the sample, UV-vis spectra was conducted at the wavelength of 200 nm to 800 nm. Subsequently, the Z-scan technique at 532 nm was performed to characterize the third-order optical nonlinear property. The final result indicate that 750? annealed CaCuO2/CaCu2O3 thin film occupy a wonderful nonlinearity , with nonlinear susceptibility X?3? as high as 1.1 × 10-12 esu, about two magnitude higher than that of the as-grown film.3.The CuO/CaTi4O9?CCTO? thin film was grown on the single crystal SrTiO3?100? substrate through the use of RF magnetron sputtering and oxygen annealing. The X-ray powder diffraction meter ?XRD? was then performed to determine the crystalline structure for the film annealed at the same temperature but different atmospheres. The high-resolution TEM, SEM and XPS were subsequently conducted to investigate compare the surface micro-structure, chemical compositions and particles distribution for the as-prepared and CuO/CaTi4O9 thin film. Additionally,UV-vis and Z-scan techniques were used to characterize the linear and nonlinear optical property of the samples. It was found that oxygen can effective enhance the film quality as well as nonlinear optical property of the CCTO thin film. The best nonlinear optical susceptibility X?3? at 650 nm was even estimated to be 6.95× 10-10 esu, with the single-pulse energy of 0.1 ?J, much higher than that of the as-prepared film. |
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