Study On Growth And Properties Of The New Nonlinear Optical Crystal Na₃La₉O₃(BO₃)₈ And Rare Earth Doped Na₃La₉O₃(BO₃)₈ Crystal

LD pumped solid-state laser (LDPSSL) is an important direction in the field of laser research. At present, one way of directly obtaining blue-green lights is through self-frequency doubling (SFD) generation. Searching for SFD crystals is good for the development of solid-state laser with high efficiency, multifunction, miniaturization and integration. Na₃La₉O₃(BO₃)₈(NLBO)is a new nonlinear optical crystal with large nonlinear optical generation and stable physical-chemical properties. Rare earth doped NLBO crystal may be a new potential SFD crystal. This dissertation includes three parts, which are growth of NLBO crystal and flux search, growth and spectral properties of rare earth doped NLBO crystal, photoluminescence properties of rare earth doped NLBO phosphor. The main results are as following:1. NLBO crystal with size of 40mm×25mm×10mm has been grown by the top-seeded solution growth method using Na₂CO₃-H₃BO₃-NaF as flux. After searching many fluxes, we find crystal growth area using Na₂CO₃-H₃BO₃-NaF as flux is narrow. Crystal quality is not obviously increased. So it is necessary to find a suitable flux for NLBO crystal growth.2. Nd:NLBO crystal has been grown by the top-seeded solution growth method. XRD pattern reveals the crystal structure of Nd:NLBO is the same as the NLBO crystal. The growth defects in Nd:NLBO crystal are observed by the white-beam synchrotron radiation topography. The concentration of Nd3+ ion has been analyzed by the inductively coupled plasma atomic emission spectrometry (ICP-AES). The absorption spectrum, emission spectrum and lifetime of Nd:NLBO crystal have been measured at room temperature. The broad absorption band around 812nm makes it suitable for the AlGaAs laser diode pumping. The Judd-Ofelt theory has been applied to the evaluation of its spectral properties. 3. Yb:NLBO crystal has been grown by the top-seeded solution growth method. XRD diffraction result shows the crystal structure of Yb:NLBO is the same as the NLBO crystal. The concentration and the segregation coefficient of Yb³⁺ ion has been determined by ICP-AES. The absorption and emission spectrum of Yb:NLBO crystal have been measured at room temperature. The broad absorption band around 812nm makes it suitable for the AlGaAs laser diode pumping. The Judd-Ofelt theory has been applied to the evaluation of its spectral properties. The emission cross section of Yb:NLBO crystal has been calculated by the reciprocal method. Three laser parameters such as minimum inversion fraction, pump saturation intensity and minimum absorption pump intensity have also been calculated.4. Er:NLBO crystal has been grown by the top-seeded solution growth method. XRD diffraction result indicates Er:NLBO has the same structure as the NLBO crystal. The concentration and the segregation coefficient of Er³⁺ ion has been investigated by ICP-AES. The absorption and emission spectrum of Er:NLBO crystal have been measured at room temperature. According to the Judd-Ofelt theory, the line strengths and the JO parameters have been calculated.5. The new oxyborate phosphors, NLBO:Eu and NLBO:Tb have been prepared by solid state reactions. The photoluminescence characteristics under UV excitation were investigated. The dominated emission of Eu3+ corresponding to the electric dipole transition ⁵D₀→⁷F₂ is located at 613 nm. It is deduced that Eu3+ is located at the site of non-inversion symmetry and replace La1 with the symmetry of C_2v. Bright green luminescence of NLBO: Tb attributed to the transition ⁵D₄→⁷F₅ is centered at 544 nm.