Piotr Miluski

Structural and optical study on antimony-silicate glasses doped with thulium ions.

Structural, spectroscopic and thermal properties of SiO₂-Al₂O₃-Sb₂O₃-Na₂O glass system doped with 0.2 mol% Tm₂O₃ have been presented. Synthesis of antimony-silicate glasses with relatively low phonon energy (600 cm(-1), which implicates a small non-radiative decay rate) was performed by conventional high-temperature melt-quenching methods. The effect of SiO₂/Sb₂O₃ ratio in fabricated Tm(3+) doped glass on thermal, structural and luminescence properties was investigated. On the basis of structural investigations decomposition of absorption bands in the infrared FTIR region was performed, thus determining that antimony ions are the only glass-forming ions, setting up the lattice of fabricated glasses. Luminescence band at the wavelength of 1.8 μm corresponding to (3)F₄→(3)H₆ transition in thulium ions was obtained under 795 nm laser pumping. It was observed that combination of relatively low phonon energy and greater separation of optically active centers in the fabricated glasses influenced in decreasing the luminescence intensity at 1800 nm.

Analysis of thermal and structural properties of germanate glasses co-doped with Yb3+/Tb3+ ions ☆

In the work the new glass compositions in the GeO2-GaO-BaO system have been prepared and thermal, structural properties of in germanate glasses co-doped with Yb(3+)/Tb(3+)ions were studied. Glasses were obtained by conventional high-temperature melt-quenching technique. The study of the crystallization kinetics processes of glasses co-doped with 0.7Yb2O3:0.7Tb2O3 was performed with DSC measurements. The activation energies have been calculated using Freedman analysis and verified with the Flynn-Wall-Ozawa method. In this order, the DSC curves have been registered with different heating rates, between 5 and 15 degrees/min. The structure of fabricated glasses has been studied by infrared and Raman spectroscopes. The effect of heat treatment on the structural properties was determined. In all glass samples the dominated infrared absorbance band at 800cm(-1) corresponds to asymmetric stretching motions of GeO4 tetrahedra containing bridging (Ge-O(Ge)) and non-bridging (Ge-O(-)) oxygens. Additionally, the influence of heat treatment on the luminescent properties was evaluated. Strong luminescence at 489, 543, 586 and 621nm corresponding to (5)D4→(7)FJ (J=6, 5, 4, 3) transitions was measured. The highest upconversion emission intensity was obtained in the germanate glass co-doped with 0.7Yb2O3/0.7Tb2O3.

Properties of Eu3+ doped poly(methyl methacrylate) optical fiber

Abstract. The proposition of trivalent europium as a luminescent dopant in poly(methyl methacrylate) (PMMA) host is presented. Optical characterization and fabrication technology of the Eu3+ doped polymeric fiber is shown. The proposed luminescent material exhibits an intense luminescence under 355- and 405-nm excitation. Additionally, the measured decay time (0.51 ms, D50→F72 transition) at third harmonic Nd:YAG excitation showed low luminescence quenching in Eu3+ chelate doped PMMA. The luminescent properties and influence of spectral attenuations on the luminescence shape in fabricated fibers are also presented.

NIR to visible upconversion in double – clad optical fiber co-doped with Yb 3+ /Ho 3+

Spectroscopic properties of a fabricated double – clad, off-set core antimony - germanate optical glass fiber co-doped with Yb3+/Ho3+ has been investigated. Upconversion luminescence of holmium ions at the wavelengths of 549 nm (5S2 (5F4) → 5I8) and 658 nm (5F5 → 5I8) was obtained as a result of the energy transfer between Yb3+ and Ho3+ ions. Glass characterized by highest intensity of upconversion luminescence (1Yb2O3/0.5Ho2O3 mol%) was used as core of double-clad optical fiber. Upconversion amplified spontaneous emission in the fabricated double – clad, off-set core optical fiber was obtained. The intensity emission ratio red (5F5→5I8)/green (5S2 (5F4)→5I8) of the fabricated optical fiber is several times higher than in bulk glass. Reabsorption of the ASE signal along the fiber resulting from Ho3+: 5S2(5F4) → 5I8,5F5 → 5I8 transitions transition was observed.

Optical fibre temperature sensor based on fluorescein and rhodamine codoped polymer layer

The article presents the luminescent based optical fiber transducer. The new construction of polymer optical fibre sensor with resonant energy transfer is shown. The idea and fabrication process of low cost optode is presented. The fluorescein and rhodamine B codoped polymethylmethacrylate (PMMA) sensitive layer exhibits the wide range of absorption spectrum ensures high source to optode spectrum alignment. The luminescent response under 430 and 470nm Light Emitting Diode (LED) source is shown. The experimental characteristic of sensor in the range from 293 K to 403 K is shown. The article presents also the potential applications of presented sensor.

Rare-earth doped materials for optical waveguides

In the paper the analysis of luminescence emission in the VIS spectra range of fabricated multicomponent glasses doped with rare-earth ions and PMMA doped with dyes were presented. Up-conversion emission in: germanate glass co-doped with 0.5Yb₂O₃/0.75Eu₂O₃ mol% under 976 nm excitation has been investigated. Down-conversion mechanism was analyzed in phosphate glasses doped with 0.5 mol% Tb₂O₃ and PMMA co-doped with fluorescein and rhodamine B. Phosphosilicate glasses doped with Er³⁺ ions have been also studied in order to fabricate target for manufacturing planar waveguides by RF-sputtering deposition. Fabricated materials can be used for fabrication of optical fibers. In result blue up-conversion emission in double-clad optical fiber with Yb³⁺/Tm³⁺- doped core was presented.

The xanthene dyes doped PMMA microspheres for optical sensor applications

The numerous applications of luminescent glass and polymeric microspheres are well known. The polymeric structures are popular as they assure good processability (solid and porous structures) and high doping level. The article presents the suspension polymerization process of polymeric (PMMA) microspheres doped by xanthene dyes: Fluorescein (Fl) and Rhodamine B (RhB). The bright luminescence at wavelengths 510nm 595nm respectively was recorded. The shape and dimension distributions of fabricated microspheres were optically determined. The article presents also potential applications of fabricated luminescent microspheres.

Yb3+/Ho3+-codoped antimony-silicate optical fiber

The emission properties of Yb³⁺/Ho³⁺-codoped antimony-silicate optical fiber has been investigated. Luminescence at 2.1 μm corresponding to ⁵I₇→ ⁵I₈ transition in holmium was obtained by energy transfer between Yb³⁺ and Ho³⁺ ions. According to the Dexter-Miyakawa model, the parameters of energy migration C_DD of the ²F_5/2 (Yb³⁺) ↔ ²F_5/2 (Yb³⁺) transition and direct energy transfer C_DA of the 2F5/2 (Yb³⁺) → ⁵I₆ (Ho³⁺) transition was calculated. The optimization of the activator content and the concentration ratio were conducted with the purpose of maximizing the efficiency of energy transfer. It made possible to select best-suited glass which was used to manufacture double-clad optical fiber. Strong and narrow bands of spontaneous emission which formed as a result of energy transfer between ytterbium and holmium ions were observed in the fiber under exciting with radiation at 978 nm wavelength.

Measurement of refractive index using capillary waveguide

The properties of medium can be often determined using its refractive index. For example the concentration of solution or dosage of components in solution can be obtained using measuring of refractive index of liquid media. This paper presents the fabricate process and properties of double layer capillary waveguide sensor for measurement of refractive index of liquids. It also presents theoretical analysis and results of experiments using this sensor.

Structural and optical properties of antimony-germanate-borate glass and glass fiber co-doped Eu3+ and Ag nanoparticles

In the paper analysis of structural and luminescent properties of antimony-germanate-borate glasses and glass fiber co-doped with 0.6AgNO3/0.2Eu2O3are presented. Heat treatment of the fabricated glass and optical fiber (400 °C, 12 h) enabled to obtain Ag nanoparticles (NPs) with average size 30-50 nm on their surface. It has been proofed that silver ions migrate to the glass surface, where they are reduced to Ag0 nanoparticles. Simultaneously, FTIR analysis showed that heat treatment of the glass and optical fiber increases the local symmetry of the Eu3+ site.