A.V. Kurochkin

Er3+ to glass matrix energy transfer in Ga–Ge–S:Er3+ system

Abstract Spectroscopic characteristics (spontaneous emission probabilities, radiative lifetimes, oscillator strengths, branching ratios and quantum efficiency) of Er 3+ in Ga 2 S 3 –GeS 2 –Er 2 S 3 glassy system are investigated by use of Judd–Ofelt theory. Lifetime measurements 4 S 3/2 level of Er 3+ in Ga 2 S 3 –GeS 2 –Er 2 S 3 glasses with various Er 3+ concentrations and optical gap energy are performed. Estimations of the non-radiative relaxation rate and the multiphonon relaxation rate demonstrate the occurrence of energy transfer from Er 3+ ion to the electronic states of the glass matrix. The way of the practical application of this non-radiative energy transfer is suggested.

Up-conversion fluorescence in Er-doped chalcogenide glasses based on GeS2-Ga2S3 system

Abstract The up-conversion fluorescence excited with 813 and 1550 nm light is investigated in glasses of the Ga2S3–GeS2–Er2S3 system. The influence of the glassy matrix composition and Er concentration on the luminescence and absorption spectra is studied. Increasing the Ga content relative to Ge decreases the erbium concentration quenching effect. The efficiency of up-conversion fluorescence has a strong dependence on thermal history of the sample. Annealing of the glasses and decreasing the synthesis temperature increase the luminescence intensity.

Up-conversion luminescence efficiency in Er-doped chalcogenide glasses

Abstract The efficiency of up-conversion luminescence of Er 3+ ions (excited by laser light operating at 810 nm) in the GeS 2 –Ga 2 S 3 :Er 2 S 3 system strongly depends on the energy position of the fundamental absorption edge. This dependence is due to non-radiative energy exchange between the electronic subsystem of the glassy matrix and excited levels of Er 3+ ions. In chalcogenide glasses Ge and Ga atoms are fourfold coordinated. Except for the M (M=Ge, Ga)–S heterobonds, the rest are M–M homobonds. These homobonds can be detected with Raman spectroscopy. The energy position of the absorption tail of the fundamental band depends on the concentration of M–M homobonds. When the concentration of these bonds increases the absorption edge shifts to longer wavelengths and the intensity of up-conversion luminescence decreases. The relative concentration of M–M bonds depends not only on composition of the glassy matrix but also on the synthesis and on concentration of extrinsic impurities such as OH − , SH − and –CH 2 –. Another cause of reduction of up-conversion luminescence intensity is the inhomogeneous distribution of REI in the Ga 2 S 3 –GeS 2 glasses. The simple model describing dependence of luminescence intensity on type of REI distribution in the glassy matrix is discussed.

Sol-gel synthesis and luminescent properties of YVO4 : Eu nanoparticles

Experimental results on the synthesis of luminescent YVO4: Eu nanoparticles with the method of metalopolymer gel decomposition are presented. The sizes of the coherent scattering regions according to the X-ray diffraction data range from 25 to 40 nm and increase with the increase of the annealing temperature from 800 to 1000°C. It was shown that the obtained nanoparticles demonstrate good luminescent properties. The luminescence intensity and lifetime of the excited state increase with the increase of the annealing temperature. Nanoparticles are good candidates to use as luminescent labels.

Laser-Induced Copper Deposition on the Surface of an Oxide Glass from an Electrolyte Solution

Continuous copper patterns were grown on the surface of oxide glass substrates through laserinduced chemical liquid-phase deposition (LCLD). The deposition was performed with the use of a continuouswave argon laser operating in a multimode regime. The deposition occurred as a result of the reducing chemical reaction initiated by laser radiation. Continuous metal patterns were produced by scanning focused laser radiation along the substrate-electrolyte interface. The morphology and the chemical composition of the deposited patterns were examined with the use of a CEM-SCAN 4 DV scanning electron microscope equipped with an energy-dispersive spectrometer. The morphology of the deposited patterns was investigated as a function of the laser radiation power and the number of scans. It was demonstrated that high-quality continuous patterns can be fabricated using one scan of the laser beam.

Glasses of the Ga2S3-GeS2 system doped with rare-earth ions (Nd3+,Er3+) as active optical materials

Physical-chemical and optical properties of glassy system Ga-Ge-S, doped with Nd3+, Er3+ were treated from viewpoints of differential-temperature analysis, Raman and luminescence spectroscopy. Strong correlation between network structure and luminescence efficiency of Ga-Ge-S:Nd, Er system is established. Increase of Ga2S3 contents in Ga-Ge-S:Nd, Er system leads to forming of ternary structure units and enhances luminescence efficiency.

Non-radiative energy transfer from Er3+ ions to the electronic states of the chalcogenide glass matrix

Lifetime spectroscopy of the chalcogenide systems Ga-Ge-S:Er 3+ and Ga-Ge-S-Se:Er 3+ has shown that the non-radiative energy transfer from rare-earth ions to the electronic states of the chalcogenide matrix is important. Numerical calculations of transition probabilities (W R , W mph , W CR ) allowed estimation of the probability of the energy transfer to the chalcogenide matrix. It was found that when the optical bandgap of the matrix approaches the Er 3+ level, the probability of such energy transfer process will increase as long as a complete resonance is not achieved.

The environment of Nd3+, Sm3+, Yb3+ in chalcogenide glasses containing gallium and germanium

Abstract The first coordination sphere of Nd 3+ , Sm 3+ and Yb 3+ in glasses of the germanium chalcogenide–gallium chalcogenide system is studied by analyzing the optical transmission spectra of 0.85GeCh 2 ·0.15Ga 2 Ch 3 glasses (where Ch=S, Se or Te) doped with chalcogenide of these metals. It is shown that the spectral shift in absorption bands of Nd 3+ is a linear function of the mean electronegativity of chalcogens in the glasses, which indicates the coincidence between the average composition of the first coordination sphere of neodymium ions and the composition of anionic subsystem in the glasses under investigation. Spectral shift of absorption bands of Sm 3+ and Yb 3+ is a non-linear function of the mean electronegativity of chalcogens in the glasses.

Temperature hysteresis of AgI phase transition in AgI–chalcogenide glass nanolayered films

Using a method of laser ablation, a number of AgI–chalcogenide glass nanolayered films has been obtained with different thicknesses of the layers (10, 25, 50, and 100 nm). In order to study α ⇆ β phase transition in AgI, X-ray phase analysis has been carried out in the temperature range from 30 to 200°C. A correlation between the layer thickness and the temperature of the α → β phase transition during the lowering of the temperature is found. An explanation of the correlation is proposed.

YVO 4 :Nd 3+ nanophosphors as NIR-to-NIR thermal sensors in wide temperature range

We report on the potential application of NIR–to–NIR Nd3+-doped yttrium vanadate nanoparticles with both emission and excitation operating within biological windows as thermal sensors in 123–873 K temperature range. It was demonstrated that thermal sensing could be based on three temperature dependent luminescence parameters: the luminescence intensity ratio, the spectral line position and the line bandwidth. Advantages and limitations of each sensing parameter as well as thermal sensitivity and thermal uncertainty were calculated and discussed. The influence of Nd3+ doping concentration on the sensitivity of luminescent thermometers was also studied.