Engineering of Glasses for Advanced Optical Fiber Applications

Advanced optical applications (such as fiber optics)demand the engineering of innovative materialswhich provide the requisite optical performance in aform with specific functionality necessary for thedesired application. We will report on recent effortsto engineer new non-oxide glasses with tailoredphoto-sensitive response, and multi-component oxideglasses optimized for use in next generation Ramanamplification applications. The ultimate performanceof such glasses relies on control of the formation andstability of defective and/or metastable structuralconfigurations and their impact on physical as well aslinear and nonlinear optical properties. Direct laserwriting has drawn considerable attention since thedevelopment of femtosecond lasers and therecognition that such systems possess the requisiteintensity to modify, reversibly or irreversibly thephysical properties of optical materials. Such“structuring” has emerged as one of several possibleroutes for the fabrication of waveguides and otherphoto-induced structures

Emission efficiency at 1 µm from low Yb3+ concentrated tellurite glass-ceramics : Alternative materials for the future rare-earth metal shortage

Glasses in the TeO2-ZnO-Bi2O3 system were prepared with up to 2.5 mol% of Yb2O3 using standard melting process and their crystallization process was investigated for the first time. No concentration quenching was observed. The thermal treatment leads to surface precipitation of crystals, the composition of which depends on the Yb2O3 content. The addition of Yb2O3 in the tellurite network promotes the precipitation of Bi2Te4O11 crystals at the expense of Zn2Te3O8 crystals. The growing of these crystals in the low Yb3+ concentrated glass during a thermal treatment increases the interaction between the Yb3+ ions leading to an enhancement of the Yb3+ emission properties which reach those of highly Yb3+ concentrated tellurite glass. Our study suggests that a thermal treatment can be a practical alternative to increase the emission efficiency of the glass prepared with 0.5 mol% of Yb2O3 to the level of the as-prepared glass doped with 2.5 mol% of Yb2O3.Peer reviewe

Study of visible, NIR, and MIR spectroscopic properties of Er3+-doped tellurite glasses and glass–ceramics

In this paper, the structural, thermal, optical, and spectroscopic properties of Er3+-doped tellurite glasses with the composition 68.25TeO2–19.5ZnO–9.75X–2.5Er2O3 (in mol%) with X = BaO, Na2O, and Bi2O3 are reported. The glasses were prepared using the standard melt quenching method. The investigated glasses exhibit low phonon energy (∼745 cm−1) and low glass transition temperature varying between 300 and 350°C depending on the glass composition. The Raman spectra show a regular tellurite structure with variations in the number of bridging and non-bridging oxygens depending on the glass composition, the Na2O and Bi2O3-containing glasses having the most and the least polymerized network, respectively. A thermal treatment of the glasses leads to the formation of crystals, the composition of which depends on the glass composition, as revealed by X-ray diffraction analysis and confirmed using scanning electron microscope-energy-dispersive spectroscopy. The precipitation of Er-containing crystals in the Na2O and BaO-containing glasses leads to an increase in the intensity of the upconversion emissions. Although the Er3+ ions remain in the amorphous part of the Bi2O3-containing glass after heat treatment, it is the precipitation of Bi3.2Te0.8O6.4 crystals in this glass, which is thought to decrease the distance between the Er3+ ions leading to an increase in the intensity of the upconversion and mid-infrared emissions.publishedVersionPeer reviewe

Preparation of glass-based composites with green upconversion and persistent luminescence using modified direct doping method

AbstractNew oxyfluorophosphate glass-based composites which exhibit not only green upconversion under 980 nm pumping but also green persistent luminescence (PeL) after being UV charged were successfully prepared using the direct doping method. The composites are composed of a glass-ceramic with Er3+ doped CaF2 crystals and of the persistent luminescent particles with the SrAl2O4:Eu,Dy composition. In the standard direct doping method, the glass melt is quenched few minutes after adding the PeL particles in the melt held at a temperature lower than the melting temperature. It is demonstrated that the direct doping method should be modified when preparing oxyfluoride glasses with PeL particles to limit not only the decomposition of the PeL particles in the glass but also the fluorine evaporation occurring during the glass preparation. Here, the composites were prepared by quenching the melt right after adding the PeL particles. The modified direct doping method allows the preparation of glass-based composites with strong green upconversion and homogeneous green persistent luminescence.</p

Spectroscopic properties of Er3+ doped germanate glasses before and after a heat treatment process

In this paper structural, thermal and optical properties of Er3+ doped germanate glasses with the composition of 63.0GeO2-9.8Ga2O3-11.1BaO-4.9X-8.8Na2O-2.5Er2O3 (in mol%), where X = ZnO, TiO2, Al2O3 and Y2O3 are reported. The investigated glasses exhibit low phonon energies (<1000 cm−1) and high glass transition temperature varying between 588 and 642 °C. The Raman spectra evidence about different polymerization degree of the glasses. The thermal treatment leads to the precipitation of various crystals, the composition of which depends on the glass composition. According to the spectroscopic properties Er3+ ions are suspected to have similar local environment in the as-prepared glasses. However, Er-doped crystals are expected to precipitate upon devitrification, which leads to significant change of the spectroscopic properties, in particular increase in the intensity of upconversion and MIR emissions is observed. It is demonstrated that the glasses with Y2O3, ZnO and TiO2 are promising glasses especially for MIR applications.publishedVersionPeer reviewe

Femtosecond laser photo-response of Ge23Sb7S70 films

Ternary chalcogenide glass films from identical parent bulk glasses were prepared by thermal evaporation (TE) and pulsed laser deposition (PLD) and subjected to 810-nm femtosecond laser exposure at both kHz and MHz repetition rates. The exposure-induced modification on the glass film\u27s surface profile, refractive index, and structural properties were shown to be a function of laser irradiance, the number of laser pulses per focal spot, and repetition rate. Film response was shown to be related to deposition technique-related density and the number of glass bonds within the irradiated focal volume. The induced changes resulted from a reduction in glass network connectivity among GeS4/2, GeS4, S-S and S3Ge-S-GeS3 units

Development of novel integrated bio/chemical sensor systems using chalcogenide glass materials

This paper reviews ongoing progress in the design and fabrication of new, on-chip, low loss planar molecular sensors. We report the details of device design, material selection and manufacturing processes used to realise high-index-contrast (HIC), compact micro-disk resonators. These structures have been fabricated in thermally evaporated As- and Ge-based chalcogenide glass films with PDMS (polydimethylsiloxane) micro-fluidic channels using standard UV lithography. Discussed are findings that demonstrate that our novel chalcogenide-based micro-fluidic device can be used as highly sensitive refractive index sensors

Celebrating Optical Glass - the International Year of Glass (2022) : feature issue introduction

We introduce the Optical Materials Express feature issue that celebrates historic and recent advances in optical glass. In honor of the United Nations declaring 2022 to be the International Year of Glass (IYOG), this issue comprises a collection of twenty-seven manuscripts that highlight processing, characterization/metrology and applications where glass has changed our world.publishedVersionNon peer reviewe

Effect of the addition of Al2O3, TiO2 and ZnO on the thermal, structural and luminescence properties of Er3+-doped phosphate glasses

Er-doped phosphate glasses were fabricated by melt-quenching technique. The changes in their thermal, structural and luminescence properties with the addition of Al2O3, TiO2 or ZnO were studied. Physical and thermal properties were investigated through density measurement and differential thermal analysis. Structural characterization was performed using the Raman and Infrared spectroscopy. In order to study the influence of the composition on the luminescence properties of the glasses, the refractive index, the luminescence spectra and the lifetime values were measured. The results show that with the addition of Al2O3 and TiO2 the phosphate network becomes more connected increasing the glass transition temperature, whereas the addition of ZnO does not show significant changes in the optical, thermal and structural properties but it leads to a larger emission cross-section at 1540 nm as compared to the other glasses. As the site of the Er3+ is not strongly affected by the change in the glass composition, we think that the emission properties of the glasses depend on the glass structure connectivity, which has an impact on the Er3+ ions solubility.Comment: 32 pages, 9 figures, 1 tabl