Jitka Pedlikova

Heavy metal oxide glasses: preparation and physical properties

Abstract Heavy metal oxide glasses have been investigated in the following systems: TeO2–PbO–PbCl2, TeO2–ZnO, Ga2O3–PbO–Bi2O3 glasses with low OH concentration were prepared. The influence of the processing conditions on the color, the structure and the optical properties of the prepared samples was also assessed. Mixtures of starting oxides were melted in various reactive conditions using Pt, Au, SiO2 and alumina crucibles. A set of physical measurements including chemical and X-ray analysis, scanning electron microscopy, absorption spectroscopy, ultraviolet and infrared absorption edges and thermo-physical properties, were carried out. Samples were doped with Nd, Pr and Er rare earth ions. Low temperature photoluminescence spectra show the expected rare earth transitions and the broad band emission of the base glass.

GeO2-PbO glassy system for infrared fibers for delivery of Er:YAG laser energy

Abstract Glasses based on GeO2 for optoelectronics application are studied. Attention is focused on the preparation of glasses of various compositions of the GeO2-PbO system under a reactive atmosphere for removing hydride impurities. The optical properties, such as infrared absorption and reflection spectra, refraction index, and absorption coefficients, influencing glass composition, are also studied.

Preparation and characterization of sulfide, selenide and telluride glasses

Abstract Chalcogenide glass systems As–S, As–Se, As–S–Se and Ge–Se–Te and those doped with rare-earth (RE) elements have been prepared and characterized by absorption spectroscopy, scanning electron microscopy and low-temperature photoluminescence. Photoluminescence spectra have been measured over a wide temperature range and the role of multi-phonon transitions in mediating the inner 4f–4f electronic transitions of excited RE3+ ions was demonstrated. A peculiar Pr related band at 1600 nm has been found in some samples. The shift of the dominant luminescence band to higher energies with increasing temperature has been observed. Both position and line width of the luminescence band are not strongly temperature dependent at lower temperatures but considerable dependence appears when room temperature is approached.

Sulfide and heavy metal oxide glasses for active fibers

Glass samples have been synthesized from sulfide and tellurite glasses. General chemical compositions are Ge0.25Ga0.10S0.65, Ge0.25Ga0.05As0.05S0.65, (TeO2)-(PbCl2)1-x with x equals 0.4 to 0.6 and (TeO2x-(ZnO)1-x with x equals 0.75 to 0.80. Samples doped with 500 to 12000 ppm rare earth in weight were also prepared. Sulfide glasses were made from pure components using a reactive atmosphere, which lead to glasses with a low OH content. Rare earth doped glasses are homogeneous when RE concentration is less than 3000 ppm. Heterogeneous inclusions arise beyond 1000 ppm RE when doping is made with chloride or oxide. Absorption and fluorescence measurements have been made. A YAG:Nd laser was used for excitation. The evolution of the fluorescence lifetime shown that the emission from the Pr3+ 1G4 level at 1.3 micrometers shows some concentration quenching above 1000 ppm Pr3+. The color and the optical quality of the tellurite glasses depend on crucible materials. Colorless samples are obtained with gold crucible while various colorations or defects are observed with Pt, SiO2 and Al2O3. Rare earth doping result in visible defects or inhomogeneities when concentration is larger than 1000 ppm. The chemical composition and the optical absorption of doped and undoped samples was examined. Fluorescence intensity of Pr and Dy is smaller in these HMO glasses than in the sulfide glasses, this results from higher phonon energy and higher OH concentration. Further development is required for future applications.

Optical properties of As2S3 layers deposited from solutions obtained by chemical reaction

AbstractThis paper deals with three approaches for the preparation of arsenic sulfide layers from solutions. First approach employs arsenic sulfide solutions obtained by dissolving powder of arsenic sulfide glass in n-propylamine. Second approach, a novel one, employs amorphous arsenic sulfide precipitated by chemical reaction of arsenic trichloride and ammonium sulfide. The precipitate was dissolved in n-propylamine. Third original approach relays on the same chemical reaction carried out in a mixture of n-propylamine and water that prevents the precipitation. By using all the approaches input arsenic sulfide solutions with a concentration of 0.33 mol/l were fabricated and applied onto glass slides by dip-coating method with withdrawing velocities of 50, 100, 200, and 250 mm/min. Applied layers dried in vacuum at 60 °C for 1 h and thermally treated at 180 °C for 30 s were characterized by optical and atomic force microscopy as well as by transmission spectroscopy in a wavelength range of 300–2500 nm. Refractive indices, thicknesses and band gaps were estimated from measured spectra. A maximum refractive index of about 2.15 at 600 nm and thicknesses up to 220 nm were determined on layers fabricated from input solutions obtained by dissolving of arsenic sulfide glass. Arsenic sulfide layers prepared on the basis of the arsenic sulfide precipitation exhibit refractive indices up around 1.90 and thicknesses up to 410 nm. Photonic band gap values on a level of 2.2 eV have been determined on these layers. On the other hands, composite layers prepared by reaction of arsenic trichloride and ammonium sulfide in the solution of n-propylamine and water exhibited low transparencies, refractive indices around 1.7 and thicknesses of about 2 µm. Three methods for the preparation of input solutions of arsenic sulfide A,B,C are presented. The solutions are applied by dip-coating method, layers dried at temperatures lower than 180 °C. Morphologies, refractive indices n at 600 nm, optical bandgaps Eg, etc. are determined.HighlightsThree approaches for the preparation of arsenic sulfide layers from solutions presented.Arsenic sulfide glass dissolved in propylamine enables to obtain layers with refractive indices up to 2.15 and thicknesses up to 220 nm.Arsenic sulfide precipitated by chemical reaction of arsenic(III) chloride and ammonium sulfide in water and dissolved in propylamine makes possible refractive indices of about 1.9.Composite absorbing layers with refractive indices around 1.65 result from chemical reaction of arsenic(III) chloride and ammonium sulfide in water and propylamine.Maximum optical bandgap of about 2.3 eV can be achieved.

Optical fibers of As2S3 glasses: preparation and characterization

Chalcogenide glasses based on arsenic sulfide (As2S3), arsenic selenide or telluride are known to exhibit high optical nonlinearities which are necessary for advanced applications in telecommunications. Both, standard optical fibers and microstructured fibers have been fabricated from chalcogenide glasses. In this paper we deal with As2S3 solid core fibers and capillary fibers coated with a polymer jacket of UV acrylate. The guiding mechanism employing the reflection on boundary of high-index glass (a refractive index of about 2.4) and hollow cavity (n=1) was confirmed by ray-optic calculations. Fibers were drawn from input As2S3 rods and tubes. The rods were prepared from extra pure arsenic and sulfur by their melting in an evacuated ampoule. The tubes were prepared by using rotational melting technique in an evacuated ampoule rotating at 1600 rpm. Rods and tubes were elongated into fibers by using a fiber drawing facilities for preparation of optical fibers from soft optical glasses. Temperatures in a range 300-400 °C and drawing velocities of about 0.1 m/s were used. Fibers were prepared either without any polymeric jacket or they were provided by a jacket of UV acrylate (n ∼ 1.5). Fibers with diameters from 0.2 to 0.4 mm were fabricated. Dimensions of prepared fibers were measured by optical microscopy without prior polishing. Transmission properties of prepared fibers were characterized by measuring angular distributions of output power at the wavelength of 670 nm. Optical losses of fibers exceeding 2 dB/m were determined by using the cut back method.

Optical fibers of As 2 S 3 glasses: preparation and characterization

Chalcogenide glasses based on arsenic sulfide (As2S3), arsenic selenide or telluride are known to exhibit high optical nonlinearities which are necessary for advanced applications in telecommunications. Both, standard optical fibers and microstructured fibers have been fabricated from chalcogenide glasses. In this paper we deal with As2S3 solid core fibers and capillary fibers coated with a polymer jacket of UV acrylate. The guiding mechanism employing the reflection on boundary of high-index glass (a refractive index of about 2.4) and hollow cavity (n=1) was confirmed by ray-optic calculations. Fibers were drawn from input As2S3 rods and tubes. The rods were prepared from extra pure arsenic and sulfur by their melting in an evacuated ampoule. The tubes were prepared by using rotational melting technique in an evacuated ampoule rotating at 1600 rpm. Rods and tubes were elongated into fibers by using a fiber drawing facilities for preparation of optical fibers from soft optical glasses. Temperatures in a range 300-400 °C and drawing velocities of about 0.1 m/s were used. Fibers were prepared either without any polymeric jacket or they were provided by a jacket of UV acrylate (n ∼ 1.5). Fibers with diameters from 0.2 to 0.4 mm were fabricated. Dimensions of prepared fibers were measured by optical microscopy without prior polishing. Transmission properties of prepared fibers were characterized by measuring angular distributions of output power at the wavelength of 670 nm. Optical losses of fibers exceeding 2 dB/m were determined by using the cut back method.

Optical fibers of As2S3glasses: preparation and characterization

Chalcogenide glasses based on arsenic sulfide (As2S3), arsenic selenide or telluride are known to exhibit high optical nonlinearities which are necessary for advanced applications in telecommunications. Both, standard optical fibers and microstructured fibers have been fabricated from chalcogenide glasses. In this paper we deal with As2S3 solid core fibers and capillary fibers coated with a polymer jacket of UV acrylate. The guiding mechanism employing the reflection on boundary of high-index glass (a refractive index of about 2.4) and hollow cavity (n=1) was confirmed by ray-optic calculations. Fibers were drawn from input As2S3 rods and tubes. The rods were prepared from extra pure arsenic and sulfur by their melting in an evacuated ampoule. The tubes were prepared by using rotational melting technique in an evacuated ampoule rotating at 1600 rpm. Rods and tubes were elongated into fibers by using a fiber drawing facilities for preparation of optical fibers from soft optical glasses. Temperatures in a range 300-400 °C and drawing velocities of about 0.1 m/s were used. Fibers were prepared either without any polymeric jacket or they were provided by a jacket of UV acrylate (n ∼ 1.5). Fibers with diameters from 0.2 to 0.4 mm were fabricated. Dimensions of prepared fibers were measured by optical microscopy without prior polishing. Transmission properties of prepared fibers were characterized by measuring angular distributions of output power at the wavelength of 670 nm. Optical losses of fibers exceeding 2 dB/m were determined by using the cut back method.

Special glasses for passive and active IR fibers for medical and biomedical applications

General chemical compositions of prepared glasses with low OH group concentrations are Ge0.25Ga0.10S0.65, Ge0.25Ga0.05As0.05S0.65, (TeO2)x - (PbCl2)1-x with x equals 0.4 to 0.6 and (TeO2)x - (ZnO)1-x with x equals 0.75 to 0.80. Samples doped with 500 to 12000 ppm rare earth in weight were prepared. Rare earth doped glasses are homogeneous when RE concentration is less than 3000 ppm. Heterogeneous inclusions arise beyond 1000 ppm RE when doping is made with chloride or oxide. Electron microscopy, absorption and fluorescence measurements have been made. YAG:Nd. Ar, He-Ne lasers were used for excitation of photoluminescence. The color and optic quality of the tellurite glasses depend on crucible materials. Rare earth doping results in visible defects or inhomogeneities when concentration is larger than 1000 ppm. The chemical composition and the optical absorption of doped and undoped samples was examined. Fluorescence intensity of Pr and Dy is smaller in these HMO glasses than in the sulfide glasses, which results from higher phonon energy and higher OH concentration. Further development is required for future applications.

Infrared materials and optical fibers for the transmission of Er:YAG and CO laser radiation

Our attention was focused on chalcogenide, heavy metal oxide glasses (TeO2/ - PbO, PbCl(subscript 2) and sapphire fibers. Improving of the purity of these glasses was achieved by their preparation in a halogen reactive atmosphere, the concentration of hydride impurities were diminished below 10-4 mol%. The values of optical losses are below 1 dB/m at 3 and 5 micrometer. The attention was focused on sapphire fibers too. The fibers about 1 mm in diameter and 200 - 300 mm in length were prepared. Their optical losses are below 1 dB/m at 3 micrometer.