Investigation of Yb 3+ -doped alumino-silicate glasses for high energy class diode pumped solid state lasers

In contrast to Yb 3+ which is a well-investigated optically active ion, the spectroscopic properties of its divalent counterpart Yb 2+ in glasses are hardly investigated, although Yb 2+ might have a notable influence on the luminescence properties of Yb 3+ -doped glasses even at low Yb 2+ concentrations because of its strong f-d transitions. In this paper, we report on the preparation and spectroscopic properties of Yb 2+ -doped aluminosilicate glasses that were produced using the normal meltquench technique. The glass composition is 20CaOÁ20Al 2 O 3 Á60SiO 2 (mol%). To achieve a sufficient amount of Yb 2+ in the samples, different methods were applied to influence the red-ox equilibrium during glass melting: firstly, under argon atmosphere and additional argon bubbling, and secondly by the addition of metallic aluminum powder to the batch. The strongly reduced samples show a greenish to brownish yellow coloring which could be attributed to the strong absorption of Yb 2+ ions in the UV to blue spectral range. The absolute Yb 2+ concentration in the glass and the molar extinction coefficient of Yb 2+ was obtained by spectroscopic measurements. If irradiated with UV light, the Yb 2+ -doped samples show a broad fluorescence emission in the wavelength range from 450 to 700 nm with a peak at around 515 nm.silicate, optical glasses, aluminosilicate glasses, ytterbium II, photoluminescence | INTRODUCTIONIn contrast to the well-studied Yb 3+ ions, investigations of its lower oxidation state Yb 2+ are hardly reported for melt-quenched glasses. However, Yb 2+ might occur besides the widely used Yb 3+ , and hence information on its optical properties and its red-ox behavior are quite essential. The optically active ion Yb 3+ is used in highpower laser materials, laser fibers and scintillator materials but also as sensitizer for energy transfer and up-conversion processes. 1-3 Recently, the Yb 3+ ion was proposed to improve the solar cell efficiency by utilizing the quantum cutting effect, as it emits close to the efficiency maximum of silicon-based solar cells at around 1000 nm. 4-6 To collect large parts of the solar spectrum, broad band f-d absorption in the UV to blue spectral region is needed. This can for example be achieved by the addition of by Ce 3+ and Eu 2+ . Additionally, the absorption and emission wavelengths of these ions can be tuned to fit the spectral requirements for quantum cutting in connection with Yb 3+ . 7,8 However, the problem in Eu 2+ /Yb 3+ and Ce 3+ / Yb 3+ co-doped materials is the formation of Eu 3+ /Yb 2+ or Ce 4+ /Yb 2+ charge transfer states, which both quench the Eu 2+ or Ce 3+ emissions which is needed for the quantum cutting process. 9,10 To determine whether these charge transfer states are formed, a good knowledge on the spectral properties of Yb 2+ in the host material is required. On the other hand, also the Yb 2+ /Yb 3+ ion pair has been proposed for quantum cutting, since Yb 2+ -as Ce 3+ and Eu 2+ -shows broad and strong absorption in the UV to visible range because of f-d transiti...

Section: Introductionmentioning

confidence: 63%

Spectroscopic properties of Yb²⁺ in aluminosilicate glass

Assadi

Herrmann

Damak

et al. 2017

“…Their OH concentrations could be minimized by bubbling of the melt with dry gases and/or by adding fluoride to the glass composition . The glasses show exceptionally high absorption and emission cross sections, and smoother and broader absorption and emission spectra than the fluoride phosphate glass and the crystalline calcium fluoride . However, this was the case for all aluminosilicate glasses that had been doped with Yb 3+ .…”

Section: Resultsmentioning

confidence: 99%

“…Fluorescence lifetimes of Sm 3+ ‐ and Eu 3+ ‐doped samples were measured using a homemade experimental setup . Yb 3+ ‐doped samples were optically characterized with the methods given in Refs and .…”

Section: Methodsmentioning

confidence: 99%

New Aluminosilicate Glasses as High‐Power Laser Materials

Herrmann

Rüssel

2015

Self Cite

In the past few years, aluminosilicate glasses of an extremely broad compositional range have been prepared and analyzed to scan this glass type for its potential use as high-power laser material. The tested network modifier ions included Li + , Na + , K + , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , Zn 2+ , Pb 2+ , Y 3+ , and La 3+ . Preliminary investigations have been conducted with Sm 3+ -and Eu 3+doped glasses; selected glass compositions have also been prepared with Yb 3+ doping for laser testing. It has been found that low refractive indices/low average molecular weights/low densities of the glasses in most cases support relatively long fluorescence lifetimes of the doped ions. It was further concluded that the phonon energy of the molecular network of the glasses does not affect the fluorescence properties of the doped samples. The mechanical properties such as Young's modulus, Vickers hardness, and fracture toughness generally increase with increasing field strength of the network modifier ion for constant stoichiometric ratios of the glass components. The lowest potential thermal stress values were found for zinc and magnesium aluminosilicate glasses, which also have relatively high field strengths. Taking all these facts into account, a ternary lithium aluminosilicate and a mixed lithium magnesium aluminosilicate glass doped with Yb 3+ have been prepared in high optical quality and tested with respect to their laser performance. The fluorescence lifetime values are somewhat lower than in wellestablished Yb 3+ -doped laser materials, such as fluoride phosphate glass or single crystalline calcium fluoride. Nevertheless, the aluminosilicate glasses show exceptionally high absorption and emission cross sections, smooth and very broad amplification profiles, as well as much better thermomechanical properties. Quantum efficiencies close to unity could be reached by consequently removing dissolved OH from the glass melt. *andreas.herrmann@uni-jena.de

“…In general, glasses containing B 2 O 3 , GeO 2 , TeO 2 , and Nb 2 O 5 have larger σ emi values. In addition to the glasses listed in Table , a new type Yb 3+ ‐doped aluminosilicate glass was also reported . This glass has a broader emission band and good thermo‐mechanical properties.…”

Section: Ytterbium Laser Glassesmentioning

confidence: 99%

“…Glass codes used in Table 6 Table 6, a new type Yb 3+doped aluminosilicate glass was also reported. 50,56,57 This glass has a broader emission band and good thermomechanical properties. However, high melting temperature and difficulty in reducing hydroxyl content in glass are main obstacles for the fabrication of high-quality aluminosilicate laser glass.…”

Section: Ytterbium Laser Glassesmentioning

confidence: 99%

Progress in Nd³⁺, Er³⁺, and Yb³⁺ doped laser glasses at Shanghai Institute of Optics and Fine Mechanics

Zhang

Jiang

2017

This paper reviews the progress made on Nd3+, Er3+, and Yb3+ doped laser glasses at SIOM, China. Key properties of Nd: phosphate and Nd: fluorophosphate (FP) laser glasses are presented and compared with the commercial laser glasses from Hoya and Schott. Also reviewed are properties of four types of Er: phosphate glasses. The development of a continuous, large‐scale melting platform producing high‐quality Nd: phosphate laser glass at SIOM is briefly described. Our study on the Stark splitting of Yb3+: 2F7/2 level indicates that mixed‐glass formers can significantly improve the Stark splitting, resulting enhancement of lasing performance of Yb: phosphate glass.