Zhongsen Yang

Synthesis, structure and properties of a new nonlinear optical material: zinc cadmium tetrathiocyanate

In this communication, a new nonlinear optical crystal of coordination complex, zinc cadmium tetrathiocyanate (ZnCd(SCN)4), is reported. It was successfully synthesized through several reactions in water. For the crystal structure, optical and thermal characterization were determined by elemental analysis, X-ray diffraction, infrared spectroscopy, differential scanning calorimeter, thermogravimetric analysis, and transmission spectrum. It belongs to the tetragonal system, space group I4, with a = 11.135(2), c = 4.3760(10) A, and z = 2. It exhibits powder SHG efficiencies superior to that of cadmium mercury thiocyanate (CMTC) and over 10 times that of urea, and the UV transparency cutoff is 290 nm, which is shifted to violet band 90 nm, compared with that of CMTC.

Thermal and laser properties of Nd:YVO4 crystal

Nd:YVO 4 crystal has been grown by Czochralski method. The data of thermal expansion and specific heat have been measured. The thermal expansion coefficients along a- and c-axis are α 1 = 2.2 × 10 -6 /K, and α 3 = 8.4 × 10 -6 /K respectively. The specific heat is 24.6 cal/mol K at 330 K. The large anisotropy along c- and a-axis of thermal expansion coefficients is explained by the structure of YVO 4 crystal. 921 mW output laser at 1.06 μm has been obtained with a 3 mm × 3 mm × 1 mm crystal sample when pumped by 1840 mW cw laser diode, and the slope efficiency is 55.5%.

Thermal and crystallographic properties of a new NLO material, urea-(d) tartaric acid single crystal

Abstract The crystallographic and thermal properties including thermal expansion coefficients and specific heat as well as differential scanning calorimeter (DSC), thermogravimetric analysis (TG) curves for a single crystal of a new organic nonlinear optical material, urea-(d)tartaric acid (UDT) are reported. It is orthorhombic and belongs to the D 2 point group and P2 1 2 1 2 1 space group, a = 17.229(6)A, b = 9.824(3)A, c = 5.056(2)A, V = 855.77A 3 , Z = 4 and D m = 1.63 g/cm 3 . The second harmonic generation (SHG) of UDT, based on powder measurement, is three times higher than that of KDP. Its transparency range is from 240 to 1395 nm.

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.

Raman spectra and laser properties of Yb-doped yttrium orthovanadate crystals

Yb-doped yttrium orthovanadate YbxY1−xVO4 (YYV), with x=0.02, crystallizes with a zircon-type structure in the tetragonal system, conforming to the space group I41/amd. The lattice constants are a=0.7122(5) and c=0.6291(3) nm at room temperature. The primitive cell contains four formula units. The Raman spectra and crystallography show no distortion of the VO4 and Y/YbO8 groups. The crystal field is similar to that of the YVO4 crystal and is suitable for the dopant Yb3+ ions. A strong absorption at 975 nm arises from the 2F7/2 to 2F5/2 transition; with a bandwidth of 70 nm it may provide a useful pump band for InGaAs diode lasers. This band is about seven times broader than that of Nd-doped yttrium aluminum garnet and more than three times as broad as that of Nd-doped yttrium orthovanadate. The measured absorption of the YYV is compared to Judd–Ofelt (JO) theory. When applied, the JO theory of parity-forbidden electric-dipole transitions of rare earth ions on noncentrosymmetric sites demonstrates good agr...

A Novel Nonlinear Optical Complex Crystal with an Organic Ligand Coordinated through an O Atom: Tetrathiocyanatocadmiummercury‐Dimethyl Sulfoxide

A novel nonlinear optical complex crystal with an organic ligand coordinated through an O atom: tetrathiocyanatocadmiummercury-dimethyl sulfoxide, [CdHg(SCN) 4 (H 6 C 2 OS) 2 ], (CMTD) is reported for the first time. Single crystals have been grown by temperature-lowering method, the crystal structure has been determined, and some physical properties are given. The relations between the crystal structure and nonlinear optical properties are also discussed.

Thermal properties of a new organometallic nonlinear optical material, triallylthiourea mercury bromide (ATMB)

Abstract Crystallographic, thermal expansion and specific heat data obtained for a single crystal of a new organometallic nonlinear optical material, triallylthiourea mercury bromide (ATMB), are reported. It is trigonal (space and point groups are R3c and C3v respectively) with lattice parameters a = b = 11.580 A , c= 28.939 A , V = 3375 A 3 . There are six formula units per cell and the density is 2.10 g/cm3. The second harmonic generation intensity, obtained on a powder sample, is 2.5 times greater than that of urea.

Space charge induced electroluminescence spectra shift in organic light-emitting diodes

The electroluminescence spectra of organic light-emitting diodes can be tuned by controlling the space charge density in the emission layer, and both red and blue shifts in the electroluminescence spectra are realized. The origin of the space charge induced spectra shift is ascribed to the space charge redistribution as response to the dipole moment variation of the organic emitters at excitation and ground states. The space charge density in the emission layer can be controlled by simply designing the device structure and layer configuration, which may have potential for optimizing the color coordinates of organic light-emitting diodes.

Facile sol-gel combustion synthesis and photoluminescence enhancement of CaZrO3:Sm3+ nanophosphors via Gd3+ doping

Abstract CaZrO3:Sm and CaZrO3:Sm, Gd nanophosphors were synthesized by a facile and efficient sol-gel combustion method. Their structure and optical properties were studied. The photoluminesce (PL) results showed that the phosphor could be efficiently excited by irradiation at wavelengths in the visible light region (350-430 nm). The CaZrO3:Sm nanophosphor exhibited strong yellow-green, orange and red emissions with peak wavelength centered at 565 nm (4G5/2→6H5/2), 601 nm (4G5/2→6H7/2) and 645 nm (4G5/2→6H9/2), respectively. The incorporation of Gd3+ ions could greatly improve the luminescence intensity. The highest emission intensity was observed with 2 mol.% Gd3+ doped CaZrO3:3 mol.% Sm powder. The material had potential application in the development of materials for LEDs and other optical devices in the visible region.

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.