Optical properties and local structure of Dy^(3+)-doped chalcogenide and chalcohalide glasses

Dy^3＋-doped Ge-Ga-Se chalcogenide glasses and GeSe2-Ga2Se3-CsI chalcohalide glasses were prepared. The absorption, emission properties, and local structure of the glasses were investigated. When excited at 808 nm diode laser, intense 1.32 and 1.55 μm near-infrared luminescence were observed with full width at half maximum （FWHM） of about 90 and 50 nm, respectively. The lifetime of the 1.32 μm emission varied due to changes in the local structure surrounding Dy^3＋ ions. The longest lifetime was over 2.5 ms, and the value was significantly higher than that in other Dy^3＋-doped glasses. Some other spectroscopic parameters were calculated by using Judd-Ofelt theory. Meanwhile, Ge-Ga-Se and GeSe2-Ga2Se3-CsI glasses showed good infrared transmittance. As a result, Dy^3＋-doped Ge-Ga-Se and GeSe2-Ga2Se3-CsI glasses were believed to be useful hosts for 1.3 μm optical fiber amplifier.

Upconversion and Near Infrared Emission of Rare Earth Ions in Chalcohalide Glass at the Early Stage of Crystallization

Nd^(3+),Er^(3+)ions doped 0.9(Ge_(0.25)Ga_(0.10)S_(0.65))-0.1CsBr chalcohalide glass were prepared via melt-quenching method,and heat treated at 360℃ in high purity Ar gas atmosphere for different hours for the early stage of crystallization.The effect of heat treatment durations on visible upconversion luminescence and near infrared emission from Nd^(3+)ions and Er^(3+)ions were investigated.The specimens kept amorphous status until the heat treatment duration extended to 10 hours,for Ga_(2)S_(3) nano-crystal formation in glass matrix.The stark splitting in visible upconversion luminescence center at 600 nm from Nd^(3+)ions weakened,and disappeared,and the shape of infrared emission centered at 1550 nm from Er^(3+)ions changed,with the heat treatment duration increased.The lifetime of Nd^(3+):^(4)F_(3/2) level and Er^(3+):^(4)I_(13/2) level dropped,then increased with heat treatment duration increased.X-ray diffraction patterns and transmission electron microscope images confirmed the amorphous state and Ga_(2)S_(3) nano-crystals formation in glass matrix.The rare earth ions local environment changes with heat treatment duration were proposed,based on the emission and lifetime changes.This research will be helpful for the understanding of rare earth doped chalcohalide crystallization mechanism and processes.

STUDY ON THE INFRARED TRANSMITTING As_2Te_3-BASED CHALCOHALIDE GLASSES

This paper reports the formation and some properties of a new class of chalcohalide glasses in the As2Tef iodide systems. The As2Te3-Pb12, As2Te3-HgI2, As2Te3-CitI and As2Te3-AgI systems can form stable bulk glasses in wide composition regions ?and no bulk glass formation was found in the As2Te3-TH sys-tem. As2Te3-based glasses have glass transition tempera-

Investigation of 2.9 μm luminescence properties and energy transfer in Tm^(3+)/Dy^(3+) co-doped chalcohalide glasses

A series of chalcohalide glasses based on the composition of 0.9（Ge30Ga5Se65）-0.1CsI with different Tm3＋/Dy3＋-codoped ions concentrations were synthesized by melt-quenching technique.The absorption spectra and 2.9 μm mid-infrared fluorescence spectra of glass samples under 800 nm laser excitation were measured.The results showed that Tm3＋ was an efficient sensitizer,which could enhance the Dy3＋： 2.9 μm fluorescence intensity significantly.The effective energy transfer between the two rare-earth ions were mainly attributed to the resonance energy transfer from Tm3＋：3F4 to Dy3＋：6H11/2 level.Emission cross section of 2.9 μm mid-infrared luminescence was also investigated according to Judd-Ofelt theory,σe=2.51×10–20 cm2.

Properties of Ag^+ Ions Alloyed Chalcohalide Glasses in GeS_2-Ga_2S_3-AgI-Ag System

The thermal, physical and optical properties as well as chemical stability of Ag+ alloyed chalcohalide glasses in the Ge S2-Ga2S3-Ag I-Ag system were investigated via the Archimedes method, differential scanning calorimetry, infrared and visible transmission spectroscopy, respectively. The glass composition can be adjusted in a large range without any devitrification. These chalcohalide glasses are optically transparent in both visible and infrared regions. They also have an improved chemical stability in deionized water, compared to other chalcohalide glasses containing halides such as CsI.

ON STRUCTURES,PROPERTIES AND CHEMICAL BOND OF Te-Se-I GLASS AND OF ADDING As,Ge ELEMENTS ONE

Te-Se glass and adding As,Ge elements to it are studied with Selt-Consistent-Field Discrete Variatioal X(a) (SEF-DV-X(a)), one of the molecule orbital calculating methods in quantum chemistry. The chemical bonding is used to discuss the relations between structures and properties with the varations of compositions of the glasses. The calculated results show that the strength of covalent and ionic bonds are both in the order of Ge-Se > As-Se > Te-Se, which is consistent with the experimental result of the glass-transition temperature (T-g) of the corresponding grasses. The Te-I bond in which I atom is one-coordinate is stronger than that in which I atom is two-coordinate, As-I and As-As bonds are both stronger than the two types of Te-I bonds. The waek Te-I bonds have been replaced by the stronger As-I and As-As bonds, which is just the reason why As addition in TeX glasses can obviously improve the thermal and chemical properties.

Microstructure and Thermal Properties of (1-x) As_2S_3-xCdCl_2 Glassy System

The homogeneous glass samples of the (1-x)As 2S 3 xCdCl 2 where x=0 and 0.05 were prepared by the conventional melt quenched method.The addition of 5mol% CdCl 2 enhanced the glass transition temperature of pure As 2S 3 glass sample by about 30℃.Based on the experimental data,the microstructure is considered to be that the discrete molecule species of AsCl 3 and nanocrystal CdS is homogeneously dispersed in the disordered polymer network formed by AsS 3 pyramids interconnected by sulfur bridges.

Microstructure and Thermal Properties of the GeS_2-In_2S_3-CsI Glasses

The-homogeneous GeS2-In2 S3-CsI glassy samples were prepared by conventional melt-quenching method. When the molar ratio of In2 S3 to Csl remains 1, the non-crystalline region can extend to the composition 0.4GeS2-0.3In2S3-0.3 CsI. And with the addition of CsI, the glass-forming ability of this serial glass reaches its maximum at the composition 0.8GeS2-0.1 In2 S3 -0.1CsI. According to the Raman spectra, the microstructure of these glasses is mainly constituted by [ GeS4 ] and [ InS4-xIx ] tetrahedra, which are interconnected by the bridging sulfur atoms ; meanwhile, the ethane-liked structural units [ S3 Ge-GeS3 ] can be formed because of the lacking of sulfur ; Cs ^＋ ion, which is added from CsI , exists as the nearest neighbor of I-ion in the glassy network.

STRUCTURES,PROPERTIES AND QUANTUM CHEMISTRY STUDIES OF As-S-X(X=Cl,Br,I)AND As-Y-Br(Y=S,Se,Te)GLASSES

As-S-X (X = Cl, Br, I) and As-Y-Br (Y = Sd Se, Te) glasses are studied with Self-Consistent-Field Discrete Variational X(a)(SCF-DV-X(a)) tone of the molecule orbital calculating methods in quantum chemistry. The chemical bonding is studied to discuss the relations between structures and properties with the variations of compositions of the glasses. The calculated results show that the strength of covalent and ionic bonds are both in the order of As-S-Cl > As-S-Br > As-S-I as well as As-S-Br > As-Se-Br > As-Te-Br, it is consistent with the experimental result of the glass-transition temperature (Tg) of the corresponding glasses. The differences of chemical bond strength and Tg among As-S-X (X = Cl ,Br ?I) glasses a-re larger are larger than those among As-Y-Br(Y = S, Se, Te) glasses and the largest difference of chemical bond strength is that of ionic bond of As-X among As-S-X (X = Cl, Br, I) glasses,so the variations of X (X = Cl, Br, I), the end atoms on the chains in the glasses, play the more important role to affect the structure and property of the glasses.

50GeSe_2-25In_2Se_3-25CsI glass doped with Tm^(3+),Tm^(3+)/Ho^(3+) and Tm^(3+)/Er^(3+) foramplifiers working at 1.22 μm

Se-based chalcohalide glass of 50GeSe2-25In2Se3-25CsI was prepared. The thermal and optical characterizations revealed that this host was thermally and optically superior for practical applications. Strong emission centered at 1.22μm was observed in all Tm3＋ sin- gle-doped, Tm3＋/Ho3＋ and Tm3＋/Er3＋ co-doped samples with an excitation of 808 nm wavelength. The emission was attributed to the Tm3＋： 3Hs-→3H6 transition. The co-doping of Ho3＋ or Er3＋ largely broadened the width and slightly strengthened the intensity of the 1.22 gm emis- sion. The possible energy transfer processes and luminescence kinetics were figured. In addition, its potential application as the host material for novel optical amplifiers was discussed.

CsCl Effected Ultrafast Third-order Optical Nonlinearities of GeS_2-Sb_2S_3 Chalcogenide Glasses

A series of alkali halide doped chalcohalide glasses （100-x）（0.9GeS2-0.1Sb2S3）-xCsCl （x=5, 10, 15 and 20 mole fraction） were prepared. The absorption spectra and Raman scatting spectra of these glasses were measured. The optical band gaps Eopt were obtained from ultraviolet absorption edges. Z-scan technique was utilized to investigate the third-order nonlinear optical properties of GeS2-Sb2S3-CsCl glasses. The value of Eopt increases and the third-order optical nonlinearity decreases with increasing CsCl content. Decreasing lone-pair electron and broadening the band-gap will provide less transition paths for nonlinear process, which play a key role in ultrafast third-order nonlinear optical responses of these chalcohalide glasses.