Jianxiu Zhang

Growth and optical properties of a new nonlinear Na 3 La 9 O 3 (BO 3 ) 8 crystal

New nonlinear crystals Na(3)La(9)O(3)(BO(3))(8) (abbreviated as NLBO) with desired morphologies, high quality and weight exceeding 40g have been grown along different directions, such as [001], [110], and [100], by top-seeded solution growth(TSSG) method. The refractive indices were accurately measured over the full transmission range, and the second-order nonlinear optical coefficients were determined by the Maker fringe technique. The optimal phase-matching (PM) conditions and the corresponding effective nonlinear coefficient were calculated for second harmonic generation (SHG) at different wavelengths. In order to confirm the correctness of our calculation, we also performed the SHG experiments under 1064 and 800 nm pumping, respectively. In addition, we directly compared the SHG performance of NLBO with that of LBO under the same experimental conditions with the 1064 nm pumping source. As the results, a conversion efficiency of 58.3% at 532 nm was obtained for NLBO, and whereas only 21.5% was obtained for LBO, indicating that NLBO is a highly attractive nonlinear material for frequency conversion of pulses into the visible and ultraviolet.

Potassium zinc borate, KZnB3O6

The title compound, KZnB3O6 contains a remarkable [B6O12]6− group ( symmetry) formed by two rings linked by edge-sharing BO4 tetrahedra, a feature that has only been observed previously under high pressure conditions. These borate groups are connected through distorted ZnO4 tetrahedra in edge-shared pairs ( symmetry), forming a three-dimensional network whose cavities are filled by K+ cations.

Diode-pumped laser properties of Nd 3+ -doped La 2 CaB 10 O 19 crystal including two-frequency generation with 4.6 THz separation

We have studied under laser diode pumping near 800 nm the continuous wave laser operation of the Nd(3+) -doped La(2)CaB(10)O(19) biaxial noncentrosymmetric crystal. From Z-oriented samples we have obtained lasing at 1051.4 nm of Nd(3+) ions located in the regular La(3+) sites. Self-frequency doubling was obtained with samples oriented at the phase matching direction of the type I ee-o nonlinear interaction. With X-oriented samples, thanks to the existence of two La(3+) and Ca(2+)-sites for the Nd(3+) location, we have obtained a two-frequency laser working in dual polarization with a frequency difference unusually large of 4.6 THz.

High-efficiency third harmonic generation at 355nm based on La 2 CaB 10 O 19

La2CaB10O19 (LCB) crystals with size up to 55 × 35 × 25 mm3 have been grown by the top-seeded solution growth (TSSG) method. The refractive indices were accurately measured over the full transmission range, and the second-order nonlinear optical coefficients were determined by the Maker fringe technique. The phase-matching(PM) conditions were calculated for third-harmonic generation (THG) at different wavelengths. The THG experiments for type I and type II LCB crystals were performed. For type I LCB, a 355 nm UV light output of 5.0 mW corresponding to the conversion efficiency of 28.3% was generated under a picosecond Nd:YAG laser, and 16 W with the efficiency of 17.5% was generated under a nanosecond 1064 nm pumping source. For type II LCB, 3.5mW THG output with conversion efficiency of 21.1% was obtained under a picosecond Nd:YAG laser, and 7.6 W with the efficiency of 7.9% was generated under a nanosecond 1064 nm pumping source. The results indicated that the LCB crystal is a promising UV nonlinear optical material because of its good THG performance and nonhygroscopicity.

355nm laser generation based on Na 3 La 9 O 3 (BO 3 ) 8 crystal

Na3La9O3(BO3)8 (NLBO) single crystals with size up to 35 × 20 × 15 mm3 have been grown by the top-seeded solution growth (TSSG) method. The phase-matching (PM) conditions and the effective nonlinear coefficients were fully calculated for third-harmonic generation (THG) at different wavelengths. The THG experiments for NLBO crystals were performed for the first time. A 355 nm UV light output of 1.9 mW was successfully obtained under a picosecond Nd:YAG laser. Through the calculations of effective nonlinear coefficients, we believe that the output power and conversion efficiency will further increase if the high optical quality NLBO samples can be utilized.

Experimental analysis of overall thermal properties of Nd:La2CaB10O19 crystals

Pure or rare-earth-ion-doped La2CaB10O19 (LCB) is a promising optical material for nonlinear frequency conversion, laser and self-frequency doubling applications. In this paper, the thermophysical properties of Nd3+-doped LCB (Nd:LCB) crystals were measured and compared with those of pure and of Yb3+- and Er3+-doped LCB, as well as other borate nonlinear optical crystals. The melting points of rare-earth-doped LCB crystals are lower than that of pure LCB. Thermal expansion coefficients along the a, b, c, c*, a*, 〈110〉 and 〈110〉* directions have been measured, and the principal expansion coefficients were calculated to be 1.85 × 10−6, 4.13 × 10−6 and 8.79 × 10−6 K−1. The measured specific heat of Nd:LCB is lower than that of pure LCB, resulting in a larger internal temperature gradient under irradiation by a pulsed laser beam. The measured thermal expansion anisotropy of Nd:LCB is stronger than that of pure LCB. The thermal conductivities of Nd:LCB along the c and c* directions are smaller than those along other crystallographic directions.

Growth, optical and electrical properties of a nonlinear optical crystal NaBa4Al2B8O18Cl3

A transparent NaBa4Al2B8O18Cl3 (NBAC) crystal with dimensions of 38 × 36 × 10 mm3 was successfully grown by the top-seeded solution growth method using a new flux NaF–NaCl. The crystallization region of NBAC is revealed in a quasi-ternary system of NBAC–NaF–NaCl. By means of eliminating the extrinsic UV absorption of Fe3+ impurity, the UV absorption edge was redetermined to be 183 nm rather than the previously reported 230 nm. The nonlinear optical (NLO) coefficients of NBAC were measured by the Maker fringe technique, which gave results of d15 = 1.27d36(KDP) = 0.49 pm V−1; d33 = 2.25d36(KDP) = 0.88 pm V−1. Calculations on the local dipole moment reveal that the NLO effect of NBAC is attributable to ClNaBa4 polyhedra, BO3 triangles, and ClBa4 tetrahedra. In addition, the ac dielectric and conductivity were measured using complex I–V method.

Diode-pumped laser and self-frequency-doubling properties of a Nd 3+ :Na 3 La 9 O 3 (BO 3 ) 8 crystal

We report efficient, diode-pumped, self-frequency doubling (SFD) in the newly developed laser crystal Nd3+:Na3La9O3(BO3)8 (Nd:NLBO). More than 730 mW of fundamental output power at 1072 nm was achieved with a slope efficiency of 16.2%. With incident pump power of 8 W, 29 mW of green cw laser emission at 536 nm was observed with proper phase matching. This initial performance and the good optical properties of the crystalline host are encouraging for the development of a high power diode-pumped SFD visible light laser source.

Nonapotassium trialuminium hexa­phosphate

In the title compound, K9Al3(PO4)6, the anionic substructure is built of interlinked [PO4] and [AlO4] tetrahedra. Each O atom of the [AlO4] tetrahedron is common to a positionally different [PO4] tetrahedron; thus, each [AlO4] tetrahedron is surrounded by four positionally different [PO4] tetrahedra. On the other hand, each [PO4] tetrahedron shares its two O atoms with two positionally different [AlO4] tetrahedra; the other two phosphate O atoms are terminal ones coordinated by K atoms. The terminal O atoms are usually closer to the K atoms than the bridging O atoms between the [AlO4] and [PO4] tetrahedra. There are nine symmetry-independent K atoms in the structure. The coordination numbers of the K atoms are 6 or 7 or 8 up to a distance of 3.31 Å. There are channels in the anionic substructure oriented along the [10] direction that are filled by K atoms.