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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Rare-Earth Doped Oxide Glasses and Fibers for Lasers Emitting in the 2÷3 μm Spectral Range
摘要： The aim of this investigation is the search of novel promising materials for solid-state and fiber lasers emitting in the spectral range 2÷3 microns, i.e. out of the range where the well-developed rare-earth doped silica fibers can successfully operate. We have stopped our choice on tellurite and calcium aluminate glasses. In contrast to silica glasses, both these glass types can contain high (>1021 cm-3) amounts of rare earth dopants. In contrast to ZBLAN glass that is widely used for mid-infrared fiber lasers, both tellurite and aluminate glasses can be quite stable to air moisture. Furthermore, calcium aluminate glasses are prominent for their extraordinary mechanical properties (better than those of fused silica). Our spectral investigations have shown that deeply dehydrated tellurite glasses (TG) are very suitable hosts for 2.3 μm Tm3+ lasers and can be also used as a host for 2.7 μm Er3+ lasers. As for calcium aluminate glasses (CAG), their phonon spectrum is not suitable for 2.7 for μm lasers. But the emission properties of Tm3+ ions in this host show some unusual feature. Two-micron Tm3+ emission band in CAG is anomalously widened and red shifted so that it overlaps well with the 2.3μm emission band. Thus continuous tuning of Tm doped CAG fiber laser from ~2μm up to ~2.4μm is conceivable. Figures 1 and 2 give some examples of bulk Tm-doped TG and CAG lasing properties. Fig. 1 shows the 2.3μm lasing parameters of 30 mm long TG sample when pumped by a pulsed ruby laser. CAG in similar conditions showed cascade lasing at 2.3μm and 2.1μm. Fig. 2 shows the lasing parameters of a quasi CW diode-pumped CAG chip laser, operating at the wavelength of 2.1 μm. Surely most practical applications of such laser glasses require fiber configuration. We have developed the laboratory technology of TG multimode and single-mode double-cladding fibers fabrication. In Tm doped TG fibers laser action at 1.9 μm and 2.3 μm was successfully demonstrated. Er doped fibers were also manufactured but 2.7 μm laser action in them requires highly reflective fiber Bragg gratings to be made in them. Fabrication of CAG fibers is a very complicated technological task due to high tendency of CAG to devitrification. Nevertheless, using “rod-in-tube” method we have prepared an optical fiber starting from Tm-doped CAG rod in a silica tube. Unfortunately, the core of this fiber contained too much SiO2 diffused from the cladding. The choice of a suitable lower-melting cladding glass should solve the problem. Thus, the properties of deeply dehydrated rare-earth doped tellurite and calcium-aluminate glasses are shown to be quite pertinent for lasers emitting in the 2÷3 μm spectral range.
关键词： rare-earth doped oxide glasses,mid-infrared spectral range,fiber lasers,tellurite glasses,calcium aluminate glasses
更新于2025-09-11 14:15:04
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Fields of application for laser beam polishing of optical glasses
摘要： Conventional manufacturing of freeform optics is expensive and elaborate. The laser beam as a polishing tool offers the possibility to produce optical surfaces fast and effective. The aim of new research on laser beam polishing of optical glasses is to achieve a polished surface finish irrespective of the surface geometrics. The carbon dioxide laser is applied to process pre-machined specimen with different roughness’s. During the polishing process an infrared camera is necessary to monitor the temperature on the surface. An annealing process reduces the process-related tensions. In addition, the cleaning process is investigated to minimize the surface damages. To characterize the surface topographic a white-light interferometer and a stylus instrument are applied. Laser beam polishing of minerals glasses such as N-BK7?, BF33? and fused silica enables surface roughness of less than Ra < 5 nm by form maintenance. By means of self-design setup, the adaption of laser beam polishing on glass cylinders, lenses or freeform is possible. As a result a parallel laser beam with a diameter of 12.65 mm is applied to process tilted surfaces up to 45°. With a laser parameter modulation, the angle-dependent absorption depending on the intensity of the laser radiation is considered.
关键词： white-light interferometer,surface finish,optical glasses,annealing process,cleaning process,infrared camera,carbon dioxide laser,laser beam polishing,stylus instrument
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - UV Luminescence in Ho:ZBLAN Glasses
摘要： Compact, short-wavelength lasers are continuously considered as one of the most attractive among all coherent light sources. A very wide range of applications such as data storage, photolithography, medical diagnostics and sterilization motivates research and development on new active materials which can efficiently emit light in the UV spectral range. There are three general methods to achieve UV and visible light emission. The first are semiconductor-based LEDs and laser diodes - in the recent years a rapid progress in the field of semiconductor lasers has been observed resulting in a variety of commercially available short-wavelength laser diodes. These impressive devices, however, are not free from some disadvantages, like poor quality of the beam and limited output power. That’s why other sources continue to attract researchers’ attention. The second method deploys nonlinear crystals, which enable obtaining short wavelength emission by the frequency multiplication. The third way to achieve UV and visible light is to directly use the optical transitions within rare earth ions in solid state media [1-2]. This work is focused on this last method.
关键词： short-wavelength emission,Ho:ZBLAN glasses,optical spectroscopy,rare earth ions,UV luminescence
更新于2025-09-11 14:15:04
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Waveguide laser potency of samarium doped BaSO4-TeO2-B2O3 glasses: Evaluation of structural and optical qualities
摘要： A series of samarium ions (Sm3+) doped barium-sulfur-telluro-borate glasses of composition (70-x)B2O3-15BaSO4-15TeO2-xSm2O3 (x ranged from 0.0 to 2.5 mol%) was prepared by melt-quenching method and examined via diverse analytical tools. Influence of changing Sm3+ doping contents on the structures and optical attributes of the proposed glasses was determined. The XRD pattern of as-quenched samples verified their glassy states. The FTIR spectra displayed the vibrational modes of tellurites and borates functional groups in the corresponding range of 460–850 cm?1 and 700–1650 cm?1. The EDX elemental maps confirmed the homogeneous distribution of the traced elements in the glass matrix. The UV–Vis–NIR absorption spectra of glasses exhibited nine distinct bands compatible with the transition from lower 6H5/2 state to the excited 6P3/2, 4I11/2, 6F11/2, 6F9/2, 6F7/2, 6F5/2, 6F3/2, 6H15/2 and 6F1/2 states of Sm3+. The photoluminescence spectra showed four emission bands allotted to magnetic dipole 4G5/2 → 6H5/2 (moderate green at 562 nm), electric dipole dominated 4G5/2 → 6H7/2 (intense orange at 598 nm), electric dipole 4G5/2 → 6H9/2 (moderate red at 645 nm) and 4G5/2 → 6H11/2 (weak red at 703 nm) transitions in Sm3+, respectively. Glasses containing Sm2O3 contents above 1.0 mol % disclosed luminescence intensity quenching. Evaluated Judd-Ofelt intensity parameters Ω2, Ω4, and Ω6 were discerned from 1.48 × 10?20–4.2 × 10?20 cm2, 2.31 × 10?20–4.31 × 10?20 cm2 and 1.26 × 10?20–1.99 × 10?20 cm2 respectively. Furthermore, the lifetime of the samples decreases with increase in Sm3+ contents as unraveled by decay curve analysis. The achieved excellent spectroscopic properties of the proposed glass composition suggested their effectiveness as visible laser for waveguide applications.
关键词： Borate glasses,Samarium ions,Waveguide laser,Bonding parameter,Radiative properties
更新于2025-09-11 14:15:04
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Physical, structural, thermal and spectroscopic investigation of Sm2O3 doped LAB glasses for orange LED
摘要： In this article, Sm2O3 doped Lithium Alumino-borate (LABS) glasses were prepared by melt-quench technique. Physical, structural, thermal and spectroscopic properties are investigated by various techniques. The emission spectra consist of three sharp peaks at 562.5, 599, 645.5 nm within the 4f electronic configuration of Sm3+ ions and two feeble emission peaks at 691, 711 nm of Sm2+ ion at 402 nm excitation. Among all prepared glass samples, glass doped with 0.5 mol % Sm2O3 (LABS-4) shows highest emission intensity with CIE chromaticity coordinates x = 0.55 and y = 0.44 in the orange zone of the chromaticity diagram. The CIE plot and the images of glass samples show; the glass doped with 0.5 mol % Sm2O3 emit intense orange light at 402 nm excitation and can be useful for intense orange LED application.
关键词： CIE Chromaticity,Orange emission,LABS glasses,Sm2O3,Photoluminescence
更新于2025-09-11 14:15:04
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High-throughput screening of laser additive manufactured metallic glass via ultrasonic wave
摘要： Laser additive manufacturing (LAM) technology provides an opportunity to fabricate bulk metallic glasses (BMGs) without any dimensional constraint and achieve the large-scale applications of BMGs. However, flaws, such as cracks, gas porosity, and crystalline phases, are always formed accompanied by the process of LAM, which seriously worsens the mechanical and physical properties of the resulting BMGs. Here, we present a novel method that involves ultrasonic wave technique to high-throughput screen the optimum process parameters for the LAM of BMG. A parameter library, constituted by a series of rectangular BMG samples, is rapidly fabricated by the LAM method under continuously changed combinations of laser power and travel speed. the ultrasonic attenuation factor, which is sensitive to the flaws, is used as the monitor to screen the parameters of the BMGs fabricated by the LAM. Using this approach, the laser power of 1300 W and travel speed of 600 mm/min are estimated as the optimum parameter combination for the LAM of a Zr51ti5ni10cu25Al9 (Zr51) BMG with the slightest flaws. The amorphous-phase dominated microstructure and the sufficiently high tensile strength of the subsequent fabricated large-sized Zr51 BMG sample verify this optimum parameter combination.
关键词： High-throughput screening,Bulk metallic glasses,Ultrasonic wave testing,Optimum process parameters,Laser additive manufacturing
更新于2025-09-11 14:15:04
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Femtosecond laser-induced large area of periodic structures on chalcogenide glass via twice laser direct-writing scanning process
摘要： We presented a theoretical and experimental study for the evolution of femtosecond laser direct-writing induced large area of periodic surface structures on As2S3 glass. The laser direct-writing induced large area of low spatial frequency LIPSS (LSFL) structures can be fabricated with the overlap rate increases from 65% to 80%. The evolution process can be defined by the competition between the laser fluence and pulse overlap rate. What is more important is that, based on secondary femtosecond laser scanning process, the interaction between the initial LSFL structures induced by the first scanning and the laser pulse of the second scanning process can induce local field enhancement effect, which can directly split the surface periodic structures of LSFL. Such new sub-sequent high spatial frequency LIPSS (HSFL) fabrication process is quite different from the traditional multi-pulse induced HSFL and can be used to fabricate large-area HSFL structures.
关键词： Nano-fabrication,Femtosecond laser,LIPSS,Chalcogenide glasses
更新于2025-09-11 14:15:04
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[IEEE 2019 21st International Conference on Transparent Optical Networks (ICTON) - Angers, France (2019.7.9-2019.7.13)] 2019 21st International Conference on Transparent Optical Networks (ICTON) - Direct Laser Writing Using Chalcogenide Thin Films
摘要： Direct laser writing has been performed in thin AMTIR-1 layers. By using 10 ns laser pulses, 250 nm thick lines have been written by tightly focusing the laser beam on the thin film layers. The possibility to enhance this resolution by using the Sb2Te3 material as super-resolution mask is also discussed.
关键词： saturable absorption,direct laser writing,Z-scan,super-resolution,nonlinear optics,chalcogenide glasses
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Polarization Dependance Engineering of Chalcogenide Optical Fiber Couplers
摘要： Chalcogenide (ChG) glasses are well known as key materials for the fabrication of optical fiber components compatible with optical transmission in the mid-infrared. Recently, single-mode ChG optical fiber couplers (OFCs) have been proposed for broadband coupling as well as for wavelength multi/demultiplexing [1]. From silica fibers, it has been shown that a proper engineering of fused optical fiber couplers can lead to polarization beamsplitting [2]. Here, we explore the polarization properties of single-mode OFCs made out of ChG glass. We show that by an appropriate engineering of their aspect ratio, the polarization dependence of OFCs is adjusted from highly polarization dependent down to polarization independent.
关键词： mid-infrared,polarization dependence,aspect ratio,Chalcogenide glasses,optical fiber couplers
更新于2025-09-11 14:15:04
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Non-linear changes of performances caused by introduction of chloride ions into Er3+-doped fluorozirconate glass
摘要： The effect of chloride ions on the properties of Er3+-doped fluorozirconate glass is systematically studied. We first observed a nonlinear mutation of the glass-forming abilities and fluorescence properties of glass when 1 mol% fluoride ions were replaced by chloride ions. The results differed from previous reports. In order to explain this special phenomenon, we investigated the changes of the structure and the Judd-Ofelt theory of glass before and after halogen anion substitution. The results indicate that part of the fluorozirconium octahedral network was destroyed and transformed into a chain structure due to the bridging chlorine atoms, of which the electronegativity is lower than F-. With the increase of Cl-, the glass-forming abilities gradually recovered due to the decrease of the liquid’s temperature. Therefore, a non-linear mutation of the glass-forming abilities was exhibited. Furthermore, the predictor χ, the ratio between the Judd–Ofelt parameters ??4 and ??6, and the reduction in phonon density caused a mutation on the fluorescence properties of glass, such as the intensity and lifetime. This research could provide a new reference for the anion modification of fluoride glass.
关键词： Non-linear changes,Halide glasses,Fluorescence properties,Thermal stability
更新于2025-09-11 14:15:04