ABSTRACT
A new mixed halide, Cs(2)HgI(2)Cl(2), which contains the highly polar tetrahedron of anion (HgI(2)Cl(2))(2-), has been designed and synthesized by reaction in solution. In its single crystal, the isolated (HgCl(2)I(2))(2-) groups are arranged to form chains. The chains are then further connected into a three-dimensional framework through the Cs atoms that occupy the empty spaces surrounded by halide atoms. All the polar (HgCl(2)I(2))(2-) groups align in such a way that gives a net polarization, leading it to show a phase matchable second harmonic generation (SHG) effect as strong as that of KH(2)PO(4) (KDP) based on the powder SHG measurement. It also displays excellent transparency in the range of 0.4-41 µm with relatively high thermal stability. A preliminary measurement indicates that its laser-induced damage threshold is about 83 MW/cm(2), about twice that of AgGaS(2). This study demonstrates that Cs(2)HgI(2)Cl(2) is a promising nonlinear optical material in the infrared region.
ABSTRACT
Temperature dependent Raman spectra of BiB3 O6 crystal and its melt were recorded and the microstructure of BiB3 O6 melt was predicted. Multiple theoretical methods including quantum chemistry ab initio calculation and DFT (Density Function Theory) methods were applied to simulate the BiB3 O6 crystal and melt structure and Raman spectra. It was demonstrated that B-O triangles and Bi lattice in the crystal reveal little affected in structure while B-O tetrahedra shows severe distortion with increasing temperature, especially B-O tetrahedra disappears after being completely melt. The microstructure of BiB3 O6 melt consists of six-member ring, [B6 O12](6-), which varies in bond lengths and angles individually. Cation Bi behaves to balance the charge of anion cluster, and the oxygen coordination number of cation Bi is 3, different from the crystal situation in which cation Bi is coordinated with 6 oxygens.
ABSTRACT
The first two members in alkaline-earth/group XI/group XIII/chalcogen system, namely Ba(2)AgInS(4) and Ba(4)AgGa(5)Se(12), were synthesized along with a Li analogue Ba(4)LiGa(5)Se(12). Ba(2)AgInS(4) crystallizes in space group P2(1)/c. It contains [AgInS(4)](4-) layers built from AgS(3) triangles and InS(4) tetrahedra with Ba(2+) cations inserted between the layers. Ba(4)AgGa(5)Se(12) and Ba(4)LiGa(5)Se(12) adopt two closely-related structure types in space group P4[combining macron]2(1)c with structural difference originating from the different positions of Ag and Li in them. The three-dimensional framework in Ba(4)AgGa(5)Se(12) is composed of GaSe(4) tetrahedra with the Ba and Ag atoms occupying the large and small channels respectively, whereas that in Ba(4)LiGa(5)Se(12) is built from LiSe(4) and GaSe(4) tetrahedra with channels to accommodate the Ba atoms. As deduced from the diffuse reflectance spectra measurement, the optical band gaps were 2.32 (2) eV, 2.52 (2) eV, and 2.65 (2) eV for Ba(2)AgInS(4), Ba(4)AgGa(5)Se(12), and Ba(4)LiGa(5)Se(12), respectively.
ABSTRACT
A new ternary germanium phosphide, NaGe(3)P(3), was obtained for the first time with the use of NaP as the reactive flux. It crystallizes in the orthorhombic space group Pmc2(1). The basic structural unit is an unprecedented [Ge(3)P(7)] ring built from one Ge(P)(4) tetrahedron, one Ge(Ge)(P)(3) tetrahedron and one Ge(Ge)(P)(2) trigonal pyramid with Ge in mixed valences of 4+, 3+ and 1+. The bonding between a tetrahedrally coordinated Ge atom and a trigonal pyramidally coordinated Ge atom (with 4s(2) lone pair of electrons) is observed for the first time in inorganic compounds. These [Ge(3)P(7)] rings are connected with each other to form two-dimensional [Ge(3)P(3)](-) layers separated by Na(+) cations. An optical band gap of 2.06(2) eV was deduced from the diffuse reflectance spectrum. Based on the electronic structure calculation, NaGe(3)P(3) is an indirect gap semiconductor with the Ge 4s, Ge 4p and P 3p orbitals strongly hybridizing around the Fermi level.
ABSTRACT
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.
ABSTRACT
The new compound Ba(5)Ga(4)Se(10) has been synthesized for the first time. It crystallizes in the tetragonal space group I4/mcm with a = 8.752(2) Å, c = 13.971(9) Å, and Z = 2. The structure contains discrete [Ga(4)Se(10)](10-) anions and charge-compensating Ba(2+) cations. The novel highly anionic [Ga(4)Se(10)](10-) cluster is composed of two Ga(Se)(4) tetrahedra and two Ga(Ga)(Se)(3) tetrahedra with Ga in the 2+/3+ valence states. It also exhibits an unusually long Ga-Se distance of 2.705(2) Å, which has only been observed under high pressure conditions before. A band gap of 2.20(2) eV was deduced from the UV/vis diffuse reflectance spectrum.
ABSTRACT
Single crystals of tribarium diyttrium hexaborate, which crystallized in the cubic system, have been obtained by spontaneous crystallization from a high-temperature melt using Li(2)O-BaO-B(2)O(3) as flux. Its structure is composed of isolated [B(2)O(5)](4-) groups, irregular BaO(9) polyhedra and regular YO(6) polyhedra which occupy alternate sites running along the [111] direction. Irregular BaO(9) polyhedra and regular YO(6) polyhedra construct a three-dimensional framework, which is reinforced by [B(2)O(5)](4-) groups.
ABSTRACT
In the crystal structure of the title organic salt, C(16)H(19)N(2) (+)·C(9)H(11)O(3)S(-)·H(2)O, the cations pack head-to-tail within a sheet and are aligned in opposite directions in neighboring sheets. The benzene ring of the anion makes an angle of 76.99â (6)° with the plane of the cationic chromophore. The cations are situated in the ab plane, whereas the benzene rings of the anions lie in the ac plane.
ABSTRACT
The new compound BaAl(4)Se(7) has been synthesized by solid-state reaction. It crystallizes in the non-centrosymmetric space group Pc and adopts a three-dimensional framework built from AlSe(4) tetrahedra and with Ba(2+) cations in the cavities. The material has a large band gap of 3.40(2) eV. It melts congruently at 901 °C and exhibits a second harmonic generation (SHG) response at 1 µm that is about half that of AgGaS(2). From a band structure calculation, BaAl(4)Se(7) is a direct-gap semiconductor with strong hybridization of the Al 3s, Al 3p, and Se 4p orbitals near the Fermi level. The calculated birefractive index is about 0.05 for wavelength longer than 1 µm and major SHG tensor elements are: d(15) = 5.2 pm V(-1) and d(13) = 4.2 pm V(-1).
ABSTRACT
The new compound BaGa(4)Se(7) has been synthesized for the first time. It crystallizes in the monoclinic space group Pc with a = 7.6252 (15) Å, b = 6.5114 (13) Å, c = 14.702 (4) Å, ß = 121.24 (2)°, and Z = 2. In the structure, GaSe(4) tetrahedra share corners to form a three-dimensional framework with cavities occupied by Ba(2+) cations. The material is a wide-band gap semiconductor with the visible and IR optical absorption edges being 0.47 and 18.0 µm, respectively. BaGa(4)Se(7) melts congruently at 968 °C and exhibits a second harmonic generation response at 1 µm that is approximately 2-3 times that of the benchmark material AgGaS(2). A first-principles calculation of the electronic structure, linear and nonlinear optical properties of BaGa(4)Se(7) was performed. The calculated birefractive indexΔn = 0.08 at 1 µm and the major SHG tensor elements are: d(11) = 18.2 pm/V and d(13) = -20.6 pm/V. This new material is a very promising NLO crystal for practical application in the IR region.
ABSTRACT
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.
Subject(s)
Crystallization/methods , Manufactured Materials , Optical Devices , Refractometry/instrumentation , Equipment Design , Equipment Failure Analysis , Materials Testing , Nonlinear DynamicsABSTRACT
In the title compound, K(9)Al(3)(PO(4))(6), the anionic substructure is built of inter-linked [PO(4)] and [AlO(4)] tetra-hedra. Each O atom of the [AlO(4)] tetra-hedron is common to a positionally different [PO(4)] tetra-hedron; thus, each [AlO(4)] tetra-hedron is surrounded by four positionally different [PO(4)] tetra-hedra. On the other hand, each [PO(4)] tetra-hedron shares its two O atoms with two positionally different [AlO(4)] tetra-hedra; 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 [AlO(4)] and [PO(4)] tetra-hedra. 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 3.31â Å. There are channels in the anionic substructure oriented along the [10] direction that are filled by K atoms.
ABSTRACT
The title compound, KZnB(3)O(6) contains a remarkable [B(6)O(12)](6-) group ( symmetry) formed by two rings linked by edge-sharing BO(4) tetra-hedra, a feature that has only been observed previously under high pressure conditions. These borate groups are connected through distorted ZnO(4) tetra-hedra in edge-shared pairs ( symmetry), forming a three-dimensional network whose cavities are filled by K(+) cations.
ABSTRACT
Crystals of ß-Zn(3)(BO(3))(PO(4)) have been grown by the Kyropoulos method. The asymmetric unit contains three Zn sites, three B-atom sites (all with symmetry 3), two P sites (both with m symmetry) and nine O-atom sites (four with m symmetry). The fundamental building units of the title structure are isolated BO(3) triangles and PO(4) tetra-hedra, which are bridged by ZnO(4) tetra-hedra or ZnO(5) trigonal bipyramids through common O atoms, leading to a three-dimensional framework structure. Some significant structural differences between the ß-polymorph and the α-polymorph are discussed.
ABSTRACT
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.
