X.F. Cheng

Preparation and Characterization of Nonlinear Optical Crystal Materials: Cadmium Mercury Thiocyanate and its Lewis Base Adducts

Cadmium mercury thiocyanate (CdHg(SCN) 4 , CMTC) and its two lewis base adducts: cadmium mercury thiocyanate dimethyl-sulphoxide (CdHg(SCN) 4 (H 6 C 2 OS) 2 , CMTD) and cadmium mercury thiocyanate glycol monomethyl ether (CdHg(SCN) 4 (C 3 H 8 O 2 ), CMTG) have been discovered as nonlinear optical (NLO) crystal materials. Their structural, optical and physicochemical properties were characterized by X-ray powder diffraction (XRPD), infrared spectroscopy, vis/UV/NIR spectra and thermal analysis. It is discovered that their transparency cutoffs lie in the UV region and CMTD crystals possess the shortest cutoff wavelength among the three crystal materials.

Characterization of mixed Nd:LuxGd1−xVO4 laser crystals

A series of laser crystals Nd:LuxGd1−xVO4 (x=0.14,0.32,0.50,0.61,0.70,0.80) was grown by the Czochralski method. The thermal properties, including the average linear thermal expansion coefficients, thermal diffusion coefficients, specific heats, and thermal conductivities, of the mixed crystals were obtained. The material constants Ms for the thermal stress resistance figure were calculated and showed that the thermal fracture limits of the mixed crystals should be comparable with that of Nd:YVO4. The polarization absorption spectra from 240to1000nm were measured at room temperature and the absorption cross sections at 809nm were calculated. Using the Judd-Ofelt theory, the theoretical radiative lifetimes were calculated and compared with the experimental results. Continuous wave laser performances were achieved with the mixed crystals at the wavelength of 1.06μm when they were pumped by a laser diode. Thermal, optical, and laser properties have shown variation as a function of x and proved that the mixed...

Spectroscopic and thermal behavior of ZnHg(SCN)4

Abstract The synthesis and purification of zinc mercury thiocyanate, ZnHg(SCN)4 (ZMTC), are described. The identity of the synthesized compound was characterized by elemental analysis, X-ray powder diffraction, infrared, Raman, and UV/Vis/NIR transmission spectra. The thermal stability and thermal decomposition of ZMTC crystal were investigated by means of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) measurements. The intermediates and final products of the thermal decomposition were identified by X-ray powder diffraction (XRPD).

Crystal growth and characterization of a new organometallic nonlinear-optical crystal material: MnHg(SCN)4(C3H8O2)

A potentially useful second harmonic generation (SHG) organometallic nonlinear-optical crystal: manganese mercury tetrathiocyanate glycol monomethyl ether, MnHg(SCN) 4 (C 3 H 8 O 2 ) (MMTG) has been prepared, and high optical quality single crystals have been successfully grown by the slow temperature-lowering technique. Its structural, physicochemical and optical properties are characterized by elemental analyses, infrared spectroscopy, transmission electron microscopy (TEM), X-ray powder diffraction, thermal analysis, powder SHG measurements and Vis/UV/NIR spectroscopy. The results of characterizations have shown that MMTG possesses good physicochemical stabilities up to 145 °C, exhibits powder SHG efficiencies close to that of urea. The UV transparency cutoff is 375 nm, and the transmission is 33.54% at 404 nm, the sample thickness was 2.76 mm, which is 6% greater than that of MnHg(SCN) 4 (MMTC).

Luminescence of CaS and MnS nanocrystallites co-activated sol–gel derived silica xerogel

Abstract CaS and MnS nanocrystallites co-activated sol–gel derived silica xerogel has been prepared by sol–gel processing. Their photoluminescence characteristics have been evaluated and compared with those of the undoped silica xerogel. Two emission bands have been observed from the doped sample, one at 440 nm while the other at 580 nm. CaS and MnS nanocrystallites embedded in sol–gel derived silica xerogel show sharp emission band. The novel luminescence phenomenon is attributed to the luminescent centers of CaS and MnS in the silica xerogel.

Growth, spectroscopic and thermal behavior of Cd(SCN)2(DMSO)2

Abstract Single crystals of the organometallic material, bis(dimethyl sulfoxide) cadmium thiocyanate (DSTC), Cd(SCN) 2 (DMSO) 2 were grown from aqueous solution. The grown crystals were characterized by elemental analyses, X-ray powder diffraction, Raman, infrared and optical transmission spectroscopy and thermal analysis. The UV transparency cutoff of DSTC crystal is 263xa0nm. It exhibits good physicochemical stability up to 134°C, and the final residue of thermal decomposition is CdS.

Preparation and properties of a novel nonlinear optical crystal: MnHg(SCN)4(H2O)2.2(C3H6CONCH3)

In this article, diaquatetrakis (thiocyanato) manganese(II) mercury(II)-N-methyl-2-pyrrolidone, MnHg(SCN) 4 (H 2 O) 2 .2(C 3 H 6 CONCH 3 ), (abbreviated as MMTWMP), a new organometallic nonlinear optical crystal material is reported. The structure, optical and thermal characterizations were determined by elemental analysis, infrared and Raman spectroscopy, X-ray powder diffraction, thermogravimetric analysis, differential scanning calorimetry, special heat, SHG measurements and UV/Vis/NIR optical transmission spectra. It belongs to the tetragonal crystallographic system, with cell parameters: a = 12.1294, c = 8.2238A, V = 1211.27 A 3 . Single crystals with dimensions up to 8 x 7 x 5 mm 3 have been obtained. The morphology of the crystals was indexed. The MMTWMP crystal exhibits good physicochemical stability at normal temperature and pressure. Its UV transparency cutoff is 360 nm, which is shifted to the violet by 13 nm, as compared with MnHg(SCN) 4 (MMTC); the optical transmission is 44. 82% at 404 nm, which is by 17.46% higher than that of MMTC.

Synthesis and optical properties of transparent ZnO–Ga2O3–SiO2 glass-ceramics embedded with cobalt-doped nanocrystals

Transparent ZnO–Ga2O3–SiO2 glass-ceramics embedded with Co2+:ZnGa2O4 nanocrystals were fabricated by the sol–gel method. X-ray diffraction, infrared spectroscopy and high-resolution transmission electron microscopy showed that the resulting material is composed of an amorphous silicate network and single-crystalline ZnGa2O4 particles. Analysis of the absorption and luminescence properties indicates that Co ions are trapped in the crystalline phase and located in the tetrahedral sites in ZnGa2O4 nanocrystals. The crystal field parameter Dq of 418xa0cm−1 and the Racah parameters B of 761xa0cm−1 and C of 3424xa0cm−1 were determined for tetrahedral Co2+ ions.