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Extending the shortest second harmonic generation output wavelength of nonlinear optical crystals into the deep ultraviolet (UV) range is important for their application as frequency conversion devices for an advanced laser. The doping of ions with a large atomic number is believed to be an effective way to realize a shorter SHG output wavelength. In this work, large-sized Sr2+-doped La2CaB10O19 (Sr:LCB) crystals with nominal ratios of 10%, 15% and 30% were grown by the top-seeded solution growth method. The measured lattice parameters of the grown Sr:LCB are nearly the same as that of the LCB crystal, and the rocking curves reveal that the grown Sr:LCB crystals are of high quality. Sr: LCB crystals have a UV cut-off edge of 168 nm. The refractive index of the Sr:LCB crystals was measured, based on which the Sellmeier equations of the Sr:LCB crystals were fitted. The calculated shortest SHG output wavelength for Type I phase matching is 270.5 nm, which is 17.5 nm shorter than that of LCB crystals (288 nm). The characterization results demonstrate that Sr:LCB is a potential nonlinear optical crystal for the deep UV range. [ABSTRACT FROM AUTHOR]

The invention and commercial application of InGaN/GaN-laser diodes have made it feasible to directly obtain the visible lasing radiation by pumping rare earth (RE) doped laser crystals. Hence searching for new laser crystals with efficient luminescence and applicable optical and physical properties in the visible range is an essential work. Here, the crystal growth and spectral properties of a series of large-size Eu3+ doped La 2 CaB 10 O 19 (Eu3+-LCB) single crystals with the nominal atomic ratios of 3%, 7%, and 10% have been well studied. High-quality Eu3+-LCB single crystals with the size of 45 × 30 × 17 mm3, was grown by top-seeded solution growth (TSSG) method. The luminescence probe was employed as the tool to identify occupation sites, demonstrating that Eu3+ ions enter into La3+ sites first, then occupy Ca2+ sites after the nominal atomic ratio of Eu3+ ions exceeds 7%. Based on the absorption and emission spectra, the intensity parameters, spontaneous transition probability, radiation lifetime, and fluorescence branch ratio for Eu3+-LCB single crystals are studied with the Judd–Ofelt theory. From the transient spectra, the emission cross-section, fluorescence decay lifetime and luminescence quantum efficiency are deduced, which exhibit the maximum performance at the nominal atomic ratio of 7% Eu3+. Combining the luminescence probe and spectral properties, it can be concluded that Eu3+ doped crystals will have the best spectral properties when Eu3+ occupation at the single La3+ sites reaches the maximum in LCB single crystals, which may be universal for RE-doped crystal with two possible occupation sites. Besides, our work demonstrates that the 7% Eu3+-LCB single crystal may be a promising medium for laser radiation in the visible region in comparison with other Eu3+ doped single crystals. • Eu3+ doped La 2 CaB 10 O 19 (Eu3+-LCB) single crystals with large size of 45 × 30 × 17 mm3 were firstly obtained by top seed solution growth. • The luminescence probe demonstrates that Eu3+ ions enter into La3+ sites first, then occupy Ca2+ sites after the nominal atomic ratio of Eu3+ ions exceeds 7%. • The spectral properties from the absorption, emission, and transient spectra demonstrate that Eu3+-LCB single crystal with the nominal ratio of 7% exhibits the maximum performance. [ABSTRACT FROM AUTHOR]

Abstract: Single crystals of La2CaB10O19 (LCB) were grown by flux method. The main physical properties of using LCB as a frequency conversion device were evaluated. The crystal has a high transparency from ultraviolet (UV) to infrared range. The four nonvanished nonlinear optical coefficients measured by Maker fringes method are 0.433, 0.484, 0.437 and 0.640pm/V for d 21, d 22, d 23 and d 14, respectively. The damage threshold of (001) plane of LCB was measured to be 11.5GW/cm2. Besides the good optical properties, the crystal also has good thermal and mechanical properties and stable chemical properties for processing and application. All these properties provide LCB with a good application prospect as a frequency conversion device. [Copyright &y& Elsevier]

Abstract: New nonlinear optical crystals La2CaB10O19 were grown by top-seeded solution growth technique from CaO–Li2O–B2O3 flux. The crystals were grown at a constant temperature gradient with special care taken in preparing the starting materials. The cooling rates between 0.24 and 0.5°C/day and the rotation rate of 45rpm are found to be suitable for growth of La2CaB10O19. The growth velocity along the positive b-axis is faster than that along the negative b-direction. The morphological faces are {001}, {110}, , , and faces, and occasionally {100} and {101} faces occur. The morphology of the as-grown crystals mainly depends on the structure of La2CaB10O19, and it is also affected by the direction of the seed. [Copyright &y& Elsevier]

Abstract: A new flux system, CaO–Li2O–B2O3, has been applied to growing La2CaB10O19 single crystals. Transparent crystals of La2CaB10O19 with a typical size of 30×25×9mm3 have been successfully grown from the new flux. The advantages of the new flux system, in terms of lower growth temperature and reduced incorporation of flux inclusions, are discussed in comparison with the previously utilized CaO·2B2O3 self-flux. [Copyright &y& Elsevier]

Abstract: A new ytterbium-doped lanthanum calcium borate crystal (Yb3+:La2CaB10O19, Yb:LCB) has been grown by the flux method. The spectroscopic properties have been investigated and the fundamental spectral parameters for Yb:LCB crystal have been calculated. Yb:LCB crystal has the strongest absorption at 976 nm with a full-width at half-maximum of 14 nm. The absorption and emission cross-sections are 1.16×10−20 and 3.51×10−20 cm2, respectively. The fluorescence lifetime is 0.95 ms. The ground-state energy level splitting is calculated to be 640 cm−1. In comparison with other Yb-doped laser crystals, the calculated parameters show that Yb:LCB crystal satisfies the fundamental spectral condition for laser emission. [Copyright &y& Elsevier]