Doped Phosphate Laser Glass Research Articles

Energy transfer mechanisms and non-radiative losses in Nd3+ doped phosphate laser glass: Dopant concentration effect study

The aim of the present work is to show a simple quantitative theoretical study on the relaxation mechanisms of the 4F3/2 levels of the Nd3+ ions in the widely used meta-phosphate laser glass system (P2O5–Al2O3–BaO–K2O) for the studied concentration range of the Nd3+ ions from 0.10 × 1020 to 8.15 × 1020 ions/cm3. Auzel's diffusion-limited model for energy transfer has been adopted in the present study for estimating zero concentration level lifetime, τ0 of 4F3/2 levels in the Nd3+ ions present in the studied glass matrix. Primarily, the relaxation mechanisms are dominated by radiative decay (krad) and energy transfer to hydroxyl groups (kOH) present in the glass network structure up to the dopant, Nd3+ concentration 0.78 × 1020 ions/cm3. Later on, with increasing dopant ion concentration, fluorescence from trivalent Nd3+ ions is unfortunately quenched by the interaction between Nd3+ ions, also known as concentration quenching. The concentration quenching of the fluorescence lifetime has been analysed using proposed Inokuti-Hirayama (I–H), Yokota-Tanimoto (Y-T) and Brushtein (B) models and found to be migration-assisted cross-relaxation mechanisms at or beyond 1.47 × 1020 ions/cm3 dopant concentration. The diffusion coefficient, D derived from the Y-T model and the energy migration rate, Wm attained from the B model has demonstrated diffusion-based energy migration initially at about >1.47 × 1020 ions/cm3 Nd3+ concentration and after that, it has switched to a hopping mechanism with further increasing ion concentration, >2.97 × 1020 ions/cm3. Critical quenching concentration, Q and critical radius, R0 for the studied glass composition have also been determined and correlated to the experimental results. No evidence for ion clustering has been found within the studied dopant ion concentration range (0.10 × 1020 - 8.15 × 1020) ions/cm3 with respect to the estimated R0. Finally, the contribution of the individual relaxation process to the experimentally recorded emission spectra and measured lifetime, τexp has been investigated in order to identify the most suitable Nd3+ ion concentration for developing large-aperture high-energy/high-peak-power lasers and optical amplifiers. Therefore, the present work is expected to be significant in aiding to formulate an effective glass composition for construction of compact high-power lasers and optical amplifiers.

稀土掺杂光功能玻璃及器件应用（特邀）

The luminescence and laser properties of rare earth are produced by the transition of 4f electrons between different energy levels. Due to its special properties, rare earth ions doped optical-functional glass have played important roles in high power laser system, whether as active or passive components. Nd3+, Er3+ doped phosphate laser glass, which have high rare earth ion doping concentration, preparation characteristics with large size and high uniformity, can be used in high energy laser as an important gain medium material; Volume Bragg grating based on Ce3+-doped Photo-Thermo-Refractive glass, is a multifunctional optical components in high power laser system, owing to its excellent wavelength and angular selectivity, high diffraction efficiency, high thermal stability and high damage threshold. In this paper the latest progress of Nd3+, Er3+ doped phosphate laser glass and Volume Bragg grating base on Ce3+-doped Photo-Thermo-Refractive glass were reported.

Effect of PbO on the spectral and thermo-optical properties of Nd3+-doped phosphate laser glass

Nd3+-doped P2O5-K2O–Al2O3–BaO-PbO phosphate glasses with various PbO/BaO ratios were synthesized using the melt quenching technique. Raman, absorption, and emission spectra were measured to investigate the effects of PbO/BaO ratios on the structures and spectroscopic properties of the glasses. The emission cross-sections of the Nd3+-doped phosphate glasses were calculated using the Judd–Ofelt theory, and were found to increase from 4.37 × 10−20 to 4.50 × 10−20 cm2 as the PbO/BaO ratio increased. In addition, thermo-optical properties were measured using an interferometric technique. The thermo-optical coefficients, which were −1.49 × 10−6, −1.65 × 10−6, and −1.64 × 10−6 K−1, respectively, were all largely negative values. The thermal expansion coefficients of the three glass samples varied within a small range. The results showed that increasing the PbO/BaO ratio of phosphate glasses can improve the laser properties while maintaining their good thermo-optical properties.

掺钕磷酸盐激光玻璃除水工艺

Nd3+-doped phosphate laser glass with the composition of 64P205-5.9A12O3-7.1K2O-19BaO-4.0Nd203(Wt%)was prepared by means of reaction atmosphere dehydration process.The dehydration efficiencies of O2+POCl3and O2+SOCl2were studied,and the influence of identical dehydrator on the fluorescence lifetime of the prepared Nd3+-doped phosphate laser glass with different dehydration time,dehydration temperature and bubbling flux were also analyzed.The results showed that the dehydration efficiency of POCl3overmatches SOCl2;the dehydration rate is the fastest at the initial bubbling stage,dehydration temperature raising benefits eliminating moisture;but it′s more appropriate to dehydrate under 1 200℃due to influence from smelting equipment and process;prolonging the dehydration time and increasing the bubbling flux are beneficial to improving dehydration efficiency;dehydration efficiency of glass is mainly influenced by the interface reaction between OH and dehydrator;fluorescence lifetime is increased with the extension of the dehydrate time and it tends to a stable valve finally;there is an optimum value for bubbling flux that is 0.8litres every minute in the experiment.

掺钕磷酸盐激光玻璃除水工艺

掺钕磷酸盐激光玻璃除水工艺

Analytical performance of host elements measurement in neodymium doped phosphate laser glasses using ICP-AES

A simple and reliable analytical method was developed using inductively coupled plasma atomic emission spectrometry (ICP-AES) for rapid simultaneous determination of aluminium, barium and potassium as host materials in neodymium doped phosphate laser glass. The method has been developed by checking the spectral interferences for the optimal line selection including determination of linearity and selectivity. The sensitivity was investigated using calibration curves obtained in presence of the matrix. Accuracy and precision of the proposed method was studied by the analysis of standard reference materials of different glass matrices and spiked in sample solution. The obtained recoveries and %RSD of those analytes were very satisfactory and as well as having no significant matrix effect. The developed method can be applied for routine analysis of phosphate laser glasses.

Investigation on the Spectroscopic Properties of Yb3+-doped Phosphate Glass

A series of the Yb3+ -doped phosphate laser glass have been prepared under high temperature and different doping content and the fluorescence and absorption spectrum is observed, respectively. The influences of the Yb3+ -doped content on the spectral properties of the glass are analyzed and the optimal mole fraction is 4 %. The emission cross-section and fluorescent lifetime is calculated with McCumber theory. Furthermore, the integrated absorption cross-section, the full width at half maximum of the emission spectra and the laser performance parameters such as least particle count, saturation pump intensity and lowest pump intensity of Yb3+ -doped laser glass is calculated.

An efficient erbium doped phosphate laser glass for high average power pumping

An efficient Er-doped phosphate laser glass CrE5 designed for high average power pumping laser operating at 1540 nm, especially for eye-safe laser surgery, was developed. This glass possesses high thermal shock resistance and excellent laser properties. The CrE5 glass can withstand 1.6 times more flashlamp pump power than ordinary phosphate glass. The ion-exchange surface strengthened glass can further endure >45% more pump power. Laser slope efficiency of 1.71% and output energy of 3.03 J were achieved at 1 Hz. The calculated laser output energy density was 15.4 J/cm 2. The laser output energy was only limited by the available pump energy in this work, and not by the thermal damage of the laser glass.

Influence of addition of B2O3 on properties of Yb3+-doped phosphate laser glass

The three host glasses doped with Yb3+ were prepared by means of conventional melt quenching technology, and the influence on physical and spectral properties of phosphate glass due to addition of B2O3 was investigated and compared with silicate glass. The results show that due to the existence of OH− impurities which induce the non-radiative route, the fluorescence lifetime of phosphate glass is shorter, so silicate glass has better spectral properties than phosphate glass. Silicate glass has more excellent thermal-mechanical properties than phosphate glass, but with the addition of B2O3, thermal-mechanical properties of phosphate glass are improved greatly without fluorescence quenching effect, and this kind of borophosphate glass will be the candidate to be used in high average power solid state laser.

Study of a new ytterbium doped phosphate laser glass

Physical, and spectral properties of a new commercial ytterbium doped phosphate laser glass with big size, NEW/Yb, was researched. Assessing from thermal mechanical property, nonlinear property, crystalline phase, micro defects and spectroscopic properties of NEW/Yb and Kigre’s QX/Yb glasses, it is found that thermal-optical properties and glass internal quality of NEW/Yb glass are superior to QX/Yb glass. For NEW/Yb, the emission cross-section and fluorescent lifetime have a value of 0.53×10 pm2 and 2.2 ms, which are higher than those of QX/Yb.