Symposium CL
Inorganic Materials Systems for Optical and Photonic Applications

Session CL-1 - Optical Materials and Photonic Structures

CL-1:IL01  Multifunctional Materials for Electronics and Photonics
F. ROSEI, Centre for Energy, Materials and Telecommunications, INRS, Varennes (QC), Canada

The bottom-up approach is considered a potential alternative for low cost manufacturing of nanostructured materials. It is based on the concept of self-assembly of nanostructures on a substrate, and is emerging as an alternative paradigm for traditional top down fabrication used in the semiconductor industry. We demonstrate various strategies to control nanostructure assembly (both organic and inorganic) at the nanoscale, developing different approaches, including: (i) control of size and luminescence properties of semiconductor nanostructures, synthesized by reactive laser ablation [1]; (ii) we developed new experimental tools and comparison with simulations are presented to gain atomic scale insight into the surface processes that govern nucleation, growth and assembly [2,3]; (iii) we devised new strategies for synthesizing multifunctional nanoscale materials to be used for electronics and photovoltaics [4-6].
[1] K. Dunn et al, Phys.Rev.B 80, 035330 (2009)
[2] F. Ratto, F. Rosei, Mater.Sci.Eng.R 70, 243 (2010)
[3] O. Moutanabbir et al, Phys.Rev.B 85, 201416 (2012)
[4] C. Yan et al, Adv.Mater. 22, 1741 (2010)
[5] R. Nechache et al., Adv.Mater. 23, 1724 (2011)
[6] R. Nechache et al, Appl.Phys.Lett. 98, 202902 (2011)


CL-1:IL02  Highly Doped Organic-inorganic Hybrid Materials for Memory and Laser Applications
M. TAKAHASHI, Department of Materials Science, Osaka Prefecture University, Sakai, Osaka, Japan

Re-writable holographic memory and low-threshold whispering gallery mode laser are fabricated with organosilicophosphite organic-inorganic hybrid materials containing rhodamine 6G dye or rare earth ions.
To be highly processable by photothermal treatment and stable at room temperature after processing, the intrinsic viscoelastic property is improved by increasing the crosslinking density of the network structure, and the photothermal conditions for efficient transfer of the irradiated photons to thermal phonons are explored. The excellent rewritability and reliabilityof the fine processed structure are found by examining the writing/erasingrepetition.　Furthermore, the origins of the changes in refractive index due to　photothermal treatment are classified into density change and　photobleaching,
Low-threshold whispering gallery mode laser was fabricated by coating Er-doped hybrid materials on the surface of silica micro particles of 100 micrometers in a diameter. Because the excellent dispesivity and high concentration of the doped ions, the excellent laser oscillation property could be obtained.


CL-1:L03  Novel Brillouin- and Raman-Suppressing Optical Fibers
J. BALLATO, T. HAWKINS, Clemson University, Anderson, SC, USA; P. Dragic, University of Illinois - Urbana Champaign, USA

Optical fibers, already ubiquitous for telecommunications, are the subject of growing attention in high energy laser applications. Such applications include directed energy systems, laser marking and cutting, oil drilling, and sensing. Present and future demands to achieve higher power levels from and through fibers are held back by parasitic nonlinearities that begin to dominate as power levels increase. Known for many years to be problematic eventually, nonlinearities are now the main limitation in continued power-scaling in most optical fiber-based systems; especially in high power systems, and particularly high-power-per-unit-bandwidth systems. Of these, Stimulated Brillouin Scattering (SBS) possesses the lowest power threshold and therefore is more problematic as it impacts performance at lower power levels. However, stimulated Raman scattering can be problematic as well. It would be highly useful to numerous industrial and commercial sectors to have optical fibers with greatly reduced SBS and Raman gain. This paper will report the current state of all0glass optical fibers derived from crystals that possess novel yet practical core compositions exhibiting markedly reduced Brillouin and Raman gain.


CL-1:L04  Sintering Yb-doped Lu2O3 Laser Hosts to Transparency Using Commercial Powders
R.F. SPEYER, B. VITALE, M. SATIN, School of Materials Science and Engineering, Georgia Inst. of Technology, Atlanta, GA, USA

Commercial powders of Lu2O3 and Yb2O3 were sintered and post-HIPed to theoretical density and good transparency. Compositions in the range of 0-12 wt% Yb2O3 were synthesized. This material combination has an optimum thermal conductivity for application as a high power laser host. Optimized processing parameters, infrared transmittance, and lasing efficiencies are described.


CL-1:L05  Structures and Properties of a Novel MgAlON Transparent Ceramics
HAO WANG, XIAO LIU, BINGTIAN TU, WEIMIN WANG, ZHENGYI FU, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, China

Transparent spinel ceramics, such as aluminum oxynitride (γ-AlON) and Magnesium aluminate (MgAl2O4), are important candidates for optical windows, domes and lenses for ultraviolet, visible, and infrared application. In recent years, it is found that MgAlON spinel solid solution can be formed in MgO-AlN-Al2O3 system. Some researches have proved that MgAlON transparent ceramics possess some improved properties such as more stable at low-temperature than γ-AlON. However, the structure and properties of MgAlON transparent ceramics is still unclear.
In this work, the MgAlON powders with a series of composition were synthesized based on the MgO-AlN-Al2O3 phase diagram, which were subsequently densified by pressureless sintering. The crystal structure of these materials containing anion positions and occupancy fractions of Mg and Al atoms was confirmed by Rietveld refinement with X-ray powder diffraction data combining with the spinel structure modeling procedure. Then the bonding structure was quantitatively analyzed by the bond valence method, and their properties such as the optical, mechanical, thermal properties as well as microstructures of MgAlON transparent ceramics were investigated. The relationship among composition, properties and microstructure were clarified.


CL-1:IL06  Heterostructures Based on Chalcogenide Glasses for Photonic Applications
V. NAZABAL¹, M. CATHELINAUD¹, B. BUREAU¹, J. CHARRIER², H. LHERMITE³, P. NEMEC⁴, G. RENVERSEZ⁵, M. CHAUVET⁶, E. RINNERT⁷, F. COLAS⁷, M. EICH⁸, M. SCHMIDT⁹, J-L. ADAM¹, ¹Chemistry Sciences Institute of Rennes, Glass & Ceramics team, UMR-CNRS 6226, University of Rennes 1, Rennes cedex, France; ²FOTON, UMR CNRS 6082, Enssat, Lannion, France; ³IETR-Microélectronique, Université de Rennes 1, Campus de Beaulieu, Rennes cedex, France; ⁴Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic; ⁵Institut Fresnel, CNRS UMR 7249, Université d'Aix Marseille, Campus de Saint Jérôme, Marseille, France; ⁶FEMTO-ST, UMR 6174, Université de Franche Comté, Besançon, France; 7IFREMER, Service Interfaces et Capteurs, Dpt. Recherches et Développements Tech., Plouzané, France; ⁸Institute of Optical and Electronic Materials, Hamburg University of Technology, Germany; ⁹Institute of Photonic Technology, Jena, Germany

Chalcogenide glasses are well-known to present specific features as a wide transparency from visible to mid-IR, a low phonon energy, a photosensitivity to light exposure or a high linear and nonlinear refractive index. Indeed, their large Kerr nonlinearities at femtosecond time scale can reach values several orders of magnitude larger than that of silica glass with flexible two-photon absorption depending on their band-gap and insignificant free carrier absorption. Chalcogenide glasses are also an important class of amorphous materials appropriate for sensing applications. Development of mid-IR sensors is a challenge of great importance for the detection of biochemical molecules. During the last decade, chalcogenide glasses have been studied under the scope of the development of all-optical signal processing based on nonlinear effects for telecommunication systems or optical sensor for the detection of biochemical molecules. For mentioned integrated optical devices, one of the key steps is the elaboration and the fabrication of chalcogenide films and heterostructures.


CL-1:IL07  Optical Applications of Artifical Magnetic Lattices
M. INOUE, H. TAKAGI, Y. NAKAMURA, PANG BOEY LIM, T. GOTO, Toyohashi University of Technology, Tohohashi, Japan

Introduction of nano-scaled artificial structures into magnetic materials provides us a variety of opportunities for controlling light. Magnetophotonic crystals (MPCs) are such the materials, where optical-order periodic structures composed of magnetic and/or dielectric materials are introduced to create photonic band gap and to confine light in the vicinity of defects in the periodic structures. Magneto-optic (MO) spatial light modulators (MOSLMs) are one of the applications of one-dimensional MPCs. Spatial light modulator (SLM) is a real-time micro-device for modulating the amplitude, phase, or polarization of light. Our recent studies suggest that the microcavity structures with MO and electro-optic (EO) composite defects are useful. The theoretical calculations revealed that very small change in voltage applied to the EO layer resulted in the large change in Kerr rotation angle without modulating the magnetization. Recently, we developed the magnetic holographic displays, which produce real 3D images without any special glasses, first in the world. The reconstructed 3D image had wide viewing angle of about 23 deg. At the conference, fundamental properties of magnetophotonic media and their applications including non-destructive inspection will be presented.


CL-1:IL11  Transparent Nano-glass-ceramic for Photonic Applications: Distribution of RE-doping Elements in the Fluoride Nano-crystals Analysed by XAS and HR-TEM
A. DE PABLOS-MARTIN², M.J. PASCUAL¹, A. DURÁN¹, ¹Instituto de Cerámica y Vidrio (CSIC), Madrid, Spain; ²Fraunhofer Institute for Mechanics of Materials IWM, Halle, Germany

Rare-earth (RE) ions-doped oxyfluoride transparent glass-ceramics contain nano-crystalline phases with very low phonon energies like LaF₃, NaLaF₄ and NaYF₄, and combine the superior optical performance of low phonon energy phases with the high mechanical, chemical and thermal stability of oxide silicates.
The insertion of the doping RE ions in the fluoride nanocrystals enhances the radiative optical emission processes currently focused on up- and down-conversion emissions. Thus, a key point to confirm the suitability of these glass-ceramics is to identify and quantify the RE ions in the fluoride nano-crystals.
X-ray absorption spectroscopy (XAS) possesses a great selectivity to discern different local chemical environment and has been previously used to characterize RE-doped glass-ceramics. We have analysed the distribution and first coordination sphere of Tm³⁺ ions in the glass and glass–ceramics of composition 55 SiO₂.20 Al₂O₃.15 Na₂O.10 LaF₃ mol % doped with 1 mol % Tm₂O₃ by using X-ray absorption near edge structure spectroscopy (XANES) and extended absorption X-ray fine structure spectroscopy (EXAFS). 
TEM and Energy Dispersive X-Ray Spectroscopy (EDXS) were used to perform elemental distribution mappings of RE elements that allow to directly localising RE ions in the glass and glass-ceramics, this study adding unexcelled spatial resolution complementing the rather integral techniques used before.


CL-1:IL12  Nearfiled Characterization of Plasmonic Materials
R. VOGELGESANG, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany

In recent years surface plasmon polaritons (SPPs)-either propagating or localized at metal−dielectric interfaces-have attracted renewed interest. On the one hand, advances in nanotechnology made the fabrication of resonant plasmonic structures feasible even for visible wavelengths. On the other hand, a growing variety of near-field optical characterization techniques are coming of age. Resonant plasmonic structures for applications at terahertz to visible wavelengths can now be studied by means well beyond conventional far-field scattering micro-spectroscopy of particle ensembles. Single particles are now routinely performed and several techniques have become available to go beyond the spatial diffraction limit of resolution in imaging of nano-plasmonic effects. We will review developments of the last few years in techniques like two-photon luminescence (TPL), electron energy loss spectroscopy (EELS), photoemission electron microscopy (PEEM), and scanning near-field optical microscopy (SNOM), highlighting selected results and open questions from both experimental studies as well as theoretical modeling.


CL-1:L14  Glass-based Photonic Crystals: from Fabrication to Applications
A. CHIAPPINI¹, A. CHIASERA¹, C. ARMELLINI^{1, 2}, A. CARPENTIERO¹, A. LUKOVIAK^{1, 3}, M. MAZZOLA¹, S. NORMANI^1,4, D. RISTIC¹, S. VALLIGATLA^{1, 5}, I. VASILCHENKO^{1, 4}, S. VARAS¹, G.C. RIGHINI^{6, 7}, M. FERRARI^{1, 7}, ¹IFN - CNR CSMFO Lab., Povo, Trento, Italy; ²FBK Center for Materials & Microsystems, Povo, Trento, Italy; ³Institute of Low Temperature and Structure Research, PAS, Wroclaw, Poland; ⁴Dipartimento di Fisica, Università di Trento, Trento, Italy; ⁵School of Physics, University of Hyderabad, Hyderabad, India; ⁶IFAC - CNR, MiPLa.b, Sesto Fiorentino, Italy; ⁷Museo Storico della Fisica e Centro di Studi e Ricerche Enrico Fermi, Roma, Italy

The control of light transport is crucial to design and tailor new photonic devices with increased optical performance in the same manner as controlling electron transport is at the basis of semiconductor and electronic technology. In recent years different types of structures have been realized with the goal of controlling light propagation through interference phenomena; in particular deep attention has been dedicated to the fabrication and the study of 1D photonic crystals and 3D colloidal systems. In this paper the authors want to highlight some of the main results obtained in the field of glass based photonic crystal systems using complementary techniques such as rf-sputtering and sol-gel route. In the specific the paper will deal with the main conditions necessary for the fabrication of high quality photonic crystals. The second part will be focused on structural, optical and spectroscopic properties of the different systems discussed. Finally possible applications of the different structures will be addressed.
Acknowledgments: This research activity was performed in the framework of the SiMeCro- CARITRO project, ITPAR Phase III (2013-2015), MAE Significant Bilateral Project between Italy and Egypt (2013-2015), and CNES R&T project SHYRO (2011-2014).


CL-1:L15  Novel Photo-Thermo-Refractive Glassceramics: Structure, Properties, Photonic and Plasmonic Applications
N.V. NIKONOROV, V.A. ASEEV, V.D. DUBROVIN, A.I. IGNATIEV, A.I. SIDOROV, E.M. SGIBNEV, St. Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg, Russia

Three types of photo-thermo-refractive (PTR) glassceramics have been developed in the present work. After exposure to UV radiation and following thermal treatment the precursor silicate glass exhibits a growth of complicated crystalline phase of NaF-AgBr on silver nanoparticles in glass host and a negative refractive index. The first PTR glassceramics was doped with erbium and ytterbium ions. This material combines itself some opportunities: fabrication of lasers or amplifiers, recording of volume Bragg gratings, and fabrication of active waveguides and fibers. The second PTR glassceramics was doped with variable halides (fluorides, bromides and chlorides). The photo-thermo-induced crystallization results in a growth of variety of nanocrystalline phases of NaF, NaBr, NaCl, AgBr, AgCl and their combinations. The growth of silver bromide and chloride phases results in a positiv e increase of refractive index. The glass host of the third PTR glassceramics contains high refractive index oxides of metals that also allowed us to increase the refractive index modulation. The structure of silver clusters and nanoparticles, and haloid nanocrystals, as well as optical, spectral, luminescent and ion-exchangeable properties of three types PTR glassceramics have been demonstrated.


CL-1:IL16  Transparent Nanoceramics for Optical Applications
W. STREK, P. GLUCHOWSKI, L. MARCINIAK, D. HRENIAK, Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw, Poland

The method of fabrication of transparent nanocrystalline ceramics of rare earth compound is presented. It is based on low temperature high pressure technique by using hot isostatic compacting at relatively low temperature 400-600 °C and high pressures 2-8 GPa. The examples of nanoceramics produced from different rare earth oxides are presented. The best quality transparent nanoceramics were obtained for RE:YAG nanocrystals synthesized by Pechini method characterized by 30-40nm size of grains. The different optical properties of RE doped nanoceramics were investigated. In particular application of RE:YAG nanoceramics for lighting, up-convertors, high temperature thermometry and anti-Stokes white emission are presented.


CL-1:L17  Upconversion Energy Transfer in Antimony - Germanate Glass Co-doped with Yb³⁺/Tm³⁺/Ho³⁺ Ions
D. DOROSZ, M. KOCHANOWICZA, J. ZMOJDAA, Bialystok University of Technology, Department of Power Engineering, Photonics and Lighting Technology, Bialystok, Poland



CL-1:IL20  Development of Novel LED Phosphor Materials using New Synthesis Techniques
K. TODA, Niigata University, Niigata, Japan

For rapid screening and synthesis of LED phosphors, we have applied novel synthesis techniques such as "Melt synthesis" and "CVD using silicon monoxide gas". These novel techniques are powerful tool for rapid screening and improvements of LED phosphor materials.
Acknowledgment
This work was partly supported by the project of Center for Transdisciplinary Research, Niigata University and NEDO, New Energy and Industrial Technology Development Organization (Rare Metal Substitute Materials Development Project Development of Technology for Reducing Tb and Eu Usage in Phosphors for Fluorescent Lamp by High-speed Material Synthesis and Evaluation).


CL-1:L23  Role of Cu+ and Crystal Water on Blue Luminescence of Copper Doped Hydronium Alunite
Y. KUROKI, S. KIMURA, T. OKAMOTO, Nagaoka University of Technology, Nagaoka, Niigata, Japan; M. TAKATA, Japan Fine Ceramics Center, Nagoya,Japan, and Nagaoka University of Technology, Nagaoka, Niigata, Japan

Alunite, KAl3(SO4)2(OH)6, is one of the most abundant sulfate minerals. The general formula for alunite is AB3(SO4)2(OH)6, where A can be K+, Na+, Rb+, Tl+, Ag+, NH4+, H3O+, Ca2+, Pb2+, Sr2+, Ba2+, Hg2+, Ce3+, and B can be Al3+, Fe3+, Cu2+, Zn2+. Natural Alunite is generally potassium deficient; this is commonly compensated by the hydronium ion (H3O+). Alunite in which K has been completely substituted by H3O+ is often called hydronium alunite ((H3O)Al3(SO4)2(OH)6) and it does not occur naturally. Our　research group demonstrated that copper-doped hydronium alunite ((H3O)Al3(SO4)2(OH)6:Cu) as a novel phosphor was successfully synthesized under hydrothermal conditions. The blue cathodoluminescence (CL) and photoluminescence (PL) peaks at about 420 nm was observed from the phosphor. In our previous studies, it was reported that the luminescence is related to the presence of Cu+ ion and structural water ( OH+ and/or H3O+ ions). In this study, the effect of the coordination environment for Cu+ and the amount of H3O+ on the luminescence properties will be discussed from the results of X-ray diffraction, X-ray fluorescence analysis, X-ray photoelectron spectroscopy, CL and PL.


CL-1:IL25  Bulk Single Crystal Growth of Oxides and Fluorides for Optical Applications
K. SHIMAMURA, E.G. VÍLLORA, National Institute for Materials Science, Tsukuba, Japan

Optical technology progress in a wide range of applications, and still demands the further development. Here, novel single crystals with advantageous characteristics will be introduced.
β-Ga2O3 exhibits the largest band gap (Eg = 4.8 eV) among TCOs. 1 and 2 inch size β-Ga2O3 single crystals were grown by the FZ and EFG techniques, respectively. Epitaxial growth of InGaN-MQW on β-Ga2O3 was realized by the MOCVD technique. Vertical structured blue LEDs on β-Ga2O3 with different packaging styles were demonstrated.
A new concept of high-brightness white LEDs based on Ce:YAG single crystal phosphor plates (SCPPs), which can overcome the conventional temperature- and photo-degradation problems, is proposed. SCPPs demonstrated excellent thermal stability with no temperature quenching, high values of luminous efficacy and increased quantum efficiency.
Tb3(Sc1-xLux)2Al3O12 (TSLAG), CeF3 and PrF3 single crystals have been designed and grown for high-power laser machinery. They showed a higher visible-UV transparency and a larger Faraday rotation than Tb3Ga5O12. They are therefore very promising material in particular for new magneto-optical isolator applications in the UV-VIS-NIR wavelength.
Authors would like to thank to Koha Co., Ltd., and Fujikura Ltd., for the collaboration.


CL-1:L26  Investigations on Luminescence Characteristics and Influence of Doping and Co-doping Different Rare Earth Ions of White Phosphorescence Materials Having Different Luminescent Centers
E. KARACAOGLU, B. KARASU, E. ÖZTÜRK, Karamanoglu Mehmetbey University, Karaman, Turkey

The white-light emitting phosphors activated by different types of rare earths were synthesized by the conventional high-temperature solid state reaction method under weak reductive atmosphere. The crystallization, particle sizes, particle morphology and photoluminescence properties of the samples have been investigated systematically by using powder X-ray diffraction (XRD), laser particle size analyser, scanning electron microscopy (SEM), photoluminescence fluorometer, respectively. The comparative results of SEM and laser particle size analysis revealed that the relatively regular morphology, smaller particle size and narrow size distribution can be achieved for the phosphor synthesized by the solid state reaction method including dry-milling below 170 meshes. The effects of rare earth oxides such as Eu2O3, Dy2O3, Ce2O3, Sm2O3, etc. on the luminescence properties of the different host materials were studied. Remarkable enhancement in luminescence characteristics of some host materials was observed when different types of rare-earth oxides were doped and co-doped and the most appropriate one was chosen, then the optimum amount of rare earths were also determined.


Session CL-2 - Advances in Characterization Techniques

CL-2:IL01  Sm-doped Glasses and Glass-ceramics for use in High-dose, High-resolution Medical Applications
S. KASAP, G. OKADA, C. KOUGHIA, S. VAHEDI, University of Saskatchewan, Canada; G. BELEV, T. WYSOKINSKI, D. CHAPMAN, The Canadian Light Source, Saskatoon, Canada; A. EDGAR, Victoria University of Wellington, New Zealand; J. UEDA, S. TANABE, Kyoto University, Japan

Sm3+ and Sm2+ ions embedded in solids exhibit different photoluminescence (PL) characteristics, and the PL emission bands can be easily distinguished. The x-ray induced conversion of Sm3+ to Sm2+ upon the absorption of radiation in a medium containing Sm3+ ions provides a means of measuring the deposited dose. Further, by using confocal fluoroluminescence microscopy, one can scan and obtain the spatial distribution of converted Sm2+ ions and hence extract the x-ray bean dose profile. We demonstrate that Sm-doped glasses that involve the Sm3+to Sm2+conversion upon x-ray irradiation can be used in Microbeam Radiation Therapy (MRT) where high-dose monitoring over the micron length scale is required. We review the current status of research, and provide new results on two basic Sm-doped glass systems (Sm-doped fluorophosphate and fluroaluminate glasses) and one glass-ceramic system based on an oxyfluoride glass with CaF2:Sm3+ nanocrystals. Experiments show that only a few selected glasses actually evince the Sm3+ to Sm2+ conversion. We describe the synthesis, structural and optical characterization, and the use of these three material systems in measuring large doses and dose profiles over the micron scale.


CL-2:L03  Near- and Mid-infrared Spectroscopic Ellipsometry for Accurate Determination of Optical Parameters of Ge-Sb-Se Glasses
P. NEMEC¹, M. OLIVIER¹, E. BAUDET², P. BENDA³, A. KALENDOVA³, V. NAZABAL^{1, 2}, ¹Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic; ²Institut des Sciences Chimiques de Rennes, UMR CNRS 6226, Equipe Verres et Céramiques, Université de Rennes 1, Rennes, France; ³Institute of Chemistry and Technology of Macromolecular Materials, Faculty of Chemical Technology, University of Pardubice, Pardubice, Czech Republic

Promising infrared transmitting materials are represented by Ge-Sb-Se glasses, which already showed excellent transparency in mid-infrared and are supposed to have high optical nonlinearity.
In this work, chalcogenide glasses from Ge-Sb-Se system with different antimony content were fabricated and their basic physico-chemical properties (chemical composition, thermal characteristics, density) were evaluated. Optical properties of the glasses were accurately studied using transmission spectroscopy, prism coupling technique and particularly spectroscopic ellipsometry covering broad spectral range (0.3-20 microns). Refractive index data show very good agreement between ellipsometry and prism coupling techniques in near-infrared range. Moreover, the reliability of infrared spectroscopic ellipsometry was demonstrated for precise determination of refractive index of chalcogenide glasses in middle-infrared spectral region. This technique, newly employed for chalcogenide glasses, has demonstrated its effectiveness for rapid, non-destructive and relatively precise measurement of refractive index.
The Czech Science Foundation (Project 13-05082S), CR MEYS (Project CZ.1.07/2.3.00/30.0058) and the CNRS PICS (Projet International de Cooperation Scientifique) program supported this work.


CL-2:IL04  Advances in Atomic Scale Characterization of Semiconductor Quantum Dots
H. EISELE, Technische Universität Berlin, Institut für Festkörperphysik, Berlin, Germany

During the past years, the development of III-V based semiconductor nanostructures has been expanded from the basic In(Ga)As/GaAs(001) system to almost all other III-V materials. The variety of III-V quantum dot nanostructures are promising candidates for device applications, such as lasers, semiconductor optical amplifiers, detectors, solar cells, and even nano-memories [1]. For all of these applications the quantum dots need to be tailored during the self-assembled growth process, in order to achieve the desired physical and/or (opto)-electronic properties. This tailoring process is mostly driven by non-equilibrium thermodynamics during the self-assembled growth process and limited by the growth kinetics. Furthermore, all quantum dot nanostructures need to be covered fully by matrix material, i.e., the self-assembled structures needs to be capped again. During this capping process the quantum dot structures and therewith their physical and (opto)-electronic properties do change again [2,3]. Therefore, it is necessary to study the atomic structure of such quantum dot depositions within the final device sample geometry, such as by cross-sectional scanning tunneling microscopy (XSTM) [4,5]. In this contribution I will present the structural characterization of different quantum dot systems with atomic resolution. I will discuss the influences of the various growth parameters on the sample growth and further on the quantum dot capping process. I will show how precisely the structural parameters such as size, shape and especially chemical composition can be determined on the atomic scale: this precise characterization enables not only a deep understanding of the growth and capping process but, most importantly, allows to optimize the growth conditions for a desired device application.
Specifically, for the about 7-8% compressively strained standard material systems In(Ga)As/GaAs(001), GaSb/GaAs(001), and InGaAs/GaP(001) typically quantum dots are comparably small in size. Further enhanced quantum dot material deposition leads to quantum rings (QR) and to destroyed material structures, such as nano voids [6-8]. Due to the surface reconstructions during the growth process, on quaternary materials, such as GaInAsP, InAs can form elongated structures in form of quantum dashes [9]. While these quantum nanostructure are based on the Stranski-Krastanov growth mode, in other material systems like the sub-monolayer growth of InAs/GaAs or the tensile strained growth of GaAs/GaSb(001) show a completely different growth behavior, which is more complicated to control and results in less ordered geometrical structures [10,11].
1. D. Bimberg, Electron. Lett. 44, 168 (2008).
2. H. Eisele et al., J. Appl. Phys. 104, 124301 (2008).
3. H. Eisele et al., Appl. Phys. Lett. 101, 233107 (2012).
4. W. Wu et al., Appl. Phys. Lett. 71, 1083 (1997).
5. H. Eisele et al., Appl. Phys. Lett. 75, 106 (1999).
6. A. Lenz et al., in Physics of Quantum Rings (Springer, Berlin, 2014).
7. A. Lenz et al., Appl. Phys. Lett. 85, 3848 (2004).
8. C. Prohl et al., Appl. Phys. Lett. 102 123102 (2013).
9. A. Lenz et al., Appl. Phys. Lett. 95, 203105 (2009).
10. A. Lenz et al., Appl. Phys. Express 3, 105602 (2010).
11. A. Lenz et al., Appl. Phys. Lett. 102, 102105 (2013).


Session CL-3 - Light Management for Active Applications

CL-3:IL01  Persistent Luminescence in ZnGa2O4:Cr, a Biomarker for Long-term in Vivo Bioimaging
B. VIANA¹, A. BESSIERE¹, S.K. SHARMA¹, D. GOURIER¹, N. BASAVARAJU², K.R. PRIOLKAR², L. BINET¹, A.J. BOS³, P. DORENBOS³, T. MALDINEY⁴, C. RICHARD⁴, D. SCHERMAN⁴, ¹Chimie-ParisTech, LCMCP, UMR - CNRS 7574, Paris Cedex, France; ²Department of Physics, Goa University, Goa, India; ³Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands; ⁴UPCGI; U 1022 Inserm; Université Paris Descartes, Chimie-ParisTech, Paris cedex, France

Optical imaging constantly demands more sensitive tools for biomedical research and medical applications. Long-lasting phosphorescence (LLP) nanoparticles emitting in the near-infrared (NIR) have been recently introduced to enable highly sensitive in vivo imaging of small animals with complete avoidance of tissue autofluorescence. The imaging technique has been improved by enhancing the LLP efficiency of various NIR-emitting LLP phosphors. In this presentation, we will present a new generation of LLP biomarkers based on chromium-doped zinc gallate (ZnGa2O4:Cr) whose LLP is exceptionally intense and most of all, can be re-activated in vivo through living tissues by using simple orange/red LEDs light.
When doped with Cr3+ ions, ZnGa2O4 (ZGO) becomes a high brightness LLP material with an emission spectrum perfectly matching the transparency window of living tissues. It allows in vivo mouse imaging with a better signal to background ratio than classical quantum dots. ZGO:Cr nanoparticles can be observed for tens of hours in living mice and the slow accumulation of LLP nanoparticles in tumors can be imaged. Mechanisms and small animal imaging will be presented.


CL-3:IL02  Transformation Optics and Invisibility Cloaks
B. ZHANG, Nanyang Technological University, Singapore, Singapore

Transformation optics, which utilized Einstein's relativity theory into optical material engineering, has emerged as an active research field in the past few years for its unprecedented power in light control, especially for its application in invisibility cloaking. The research in optical cloaking also has inspired the application of thermal cloaking to hide objects from temperature fields. On the other hand, these invisibility cloaks are typically difficult to implement in practice because of their strict requirement in materials' properties. Here, we propose some simplifications of previous transformation-based invisibility cloaks in both optics and thermodynamics. The simplified optical cloak utilized incoherence of natural light that does not require transformation of electromagnetic space such that superluminal propagation can be avoided. The simplified thermal cloak utilized an untra-thin layer to realize three-dimensional thermal cloaking for conductive heat transfer. Both have been demonstrated in experiments.


CL-3:L03  Thermo-Chromo-Luminescent Compounds: Mn(II) doped ZnAl2O4 as Thermal History Sensor
L. CORNU, V. JUBERA, M. DUTTINE, M. MÉNÉTRIER, M. GAUDON, CNRS, Univ. Bordeaux, ICMCB, UPR 9048, Pessac, France

Thermo-chromo-luminescent materials get tunable photoluminescence wavelength with a variation of temperature and can be used as thermal sensor.
In spinel structure matrix ZnAl2O4, the cations distribution in both sites (tetrahedral and octahedral) is known to depend on synthesis temperature. The cations distribution can be described by the d parameter (inversion rate) with the composition formulae (Zn(1-d)Ald)[Al(2-d)Znd]O4, d (0 ≤ d ≤ 1). The compounds are obtained using the Pechini synthesis process.
Firstly, the cations distribution of the ZnAl2O4 un-doped matrix was studied versus the synthesis temperature by XRD, SEM, diffuse reflectance and luminescence measurements. Optical measurements have evidenced that this host matrix exhibits three low intense emission bands, at different wavelengths. These emissions can be correlated to various matrix defects: cationic vacancies, cation interstitial position and antisite cations (zinc in octahedral sites).
Secondly, the influence of the thermal history on the luminescence of the Mn(II)-doped ZnAl2O4 compounds was studied. A drastic switch of the luminescence color, from red to green, which is associated to Mn(II) in octahedral and tetrahedral sites, takes place between the samples elaborated at 1200°C and 1350°C, respectively.


CL-3:L05  Optical Sensing Properties Based on a Reversible Redox Process
L. CORNU, M. GAUDON, P. VEBER, A. VILLESUZANNE, S. PECHEV, O. TOULEMONDE, M. JOSSE, R. DECOURT, V. JUBERA, ICMCB-CNRS, Pessac Cedex, France

Development of selective and specific sensor has been attracted considerable attention for a decade. Optical sensing systems are compatible with distance testing keeping the excitation and detection system out of the sensing zone. They are suited to the on board technologies and multiple light sources and detectors are now available for the obtaining of compact and robust systems. To detect an event means that a significant change of the optical properties has to occur.
We focus this work on an interesting luminescent materials that presents a reversible redox phenomenon under irradiation or temperature. The ignition and the extinction of the blue and red emission is related to the oxidation and reduction processes between trivalent cerium and indium ions under UV irradiation. Single crystals are grown using the Bridgman technic. The irradiated crystal zones are stable during at least a decade if not irradiated or heated. This strong stability suggests a local reorganization of the atomic array. A hypothesis based on DFT calculation is proposed to support the luminescence observations performed between 10 K and 300 K. Cycling of the materials also illustrates the capability of these materials to be used as optical sensors.


CL-3:IL06  Development of Efficient Solar-pumped Laser for Renewable Energy Source
S. WADA¹, T. OGAWA¹, M. HIGUCHI², ¹RIKEN, Saitama, Japan; ²Hokkaido University, Japan

With global environmental and energy issues receiving much attention, research is being intensively carried out worldwide to develop clean, efficient energy sources. Sunlight is an important source of clean energy. One way of using solar energy is to convert it to laser energy. Solar-pumped laser technology involves focusing sunlight with a lens onto laser crystals to produce laser beams from a resonator. Since electrical power is not required for such laser technology, this next-generation technology offers great promise for the future. However, since the conversion efficiency from solar energy to laser energy is only a few percent, solar-pumped lasers are not yet in practical use. Problems include the difficulty in concentrating the sunlight and the inefficiency of laser oscillation. To improve the efficiency of solar-pumped lasers, the selection of a suitable crystal is the most important factor.
In the work, we attempted to grow new laser crystals to increase the absorption of solar energy with wide spectrum. Nd3+,Cr3+-codoped YVO4 and CaYAlO4 crystals were grown for the first time to the best of our knowledge. Excellent optical properties of these crystals were obtained for the uses as the solar-pumped laser materials.


CL-3:IL07  Femtosecond Laser Processing of Glass Materials for Assembly-free Fabrication of Photonic Microsensors
LEI YUAN, XINWEI LAN, JIE HUANG, HAI XIAO, Department of Electrical and Computer Engineering, Clemson University, Clemson, SC, USA

Research and development in photonic micro/nano devices and structures have experienced a significant growth in recent years, fueled by their broad applications as sensors for in situ measurement of a wide variety of physical, chemical and biological quantities. Recent advancement in ultrafast and ultraintense pulsed laser technology has opened a new window of opportunity for one-step fabrication of micro- and even nano-scale 3D structures in various solid materials. When used for fabrication, fs lasers have many unique advantages such as negligible cracks, minimal heat-affected-zone, low recast, and high precision. These advantages enable the unique opportunity to fabricate integrated sensors with unprecedented performance, enhanced functionalities and improved robustness. This talk summarizes our recent research progresses on the understanding, design, fabrication, characterization of various photonic sensors for energy, defense, environmental, biomedical and industry applications. Femtosecond laser processing/ablation of various glass materials (fused silica, doped silica, sapphire, etc.) will be discussed towards the goal of one-step fabrication of novel photonic sensors and new enabling photonic devices. A number of new photonic devices and sensors will be presented.


CL-3:IL09  Nanoscale Chemical Imaging of Plasmonic Hot-spots beyond the Diffraction Limit
B. LAHIRI*, G. HOLLAND, V. AKSYUK, A. CENTRONE, Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland, USA; *Present Address: School of Engineering, University of Glasgow, Glasgow, UK

For many applications, such as organic photovoltaics, therapeutics etc. it is required to determine both the physical and chemical properties of nanomaterials at the local level. At the same time, the ability to image plasmonic and photonic modes at nanoscale is fundamental to new optical devices used in numerous applications such as solar energy harvesting, single molecule sensing etc. Although, we have large number of high resolution imaging techniques available (e.g. SEM, AFM etc.) that provides morphological information at the nanoscale, the chemical information of nanomaterials are obtained over a large-scale area (typically at tens of micrometre for FTIR), thereby resulting in information being obtained as an average over a number of heterogeneous nano-objects. Photo Thermal Induced Resonance (PTIR) is a new technique that circumvents this problem by combining the lateral resolution of an Atomic Force Microscopy and the chemical specificity of IR spectroscopy to locally characterize nanomaterials. In this work, the PTIR technique was applied to image dark and bright plasmonic modes of asymmetric split ring resonators with nanoscale resolution along with mapping the local absorption enhancement of polymers coated on A-SRRs, revealing hot-spots with huge local enhancement.
 
 
Session CL-4 - Advances in Research and Applications

CL-4:IL01  Multi-harmonic Generation in Micro-structured Ferroelectrics
M.O. RAMIREZ, L. MATEOS, P. MOLINA, L.E BAUSÁ, Dpto. Física de Materiales and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Madrid, Spain

Ferroelectric patterning is often used in advanced photonics and optoelectronic devices to increase their operational bandwidth and functionality providing novel and unique performances. In fact, alternate ferroelectric domains structures with increasingly smaller sizes and periods are ever more required to control the generation and light distribution in several scientific and technologically relevant fronts.
Here, careful processing based on e-beam lithography and poling has been employed to demonstrate a step forward in the range of harmonic generation with currently available broadband sources in the VIS-NIR. We experimentally show the possibility to obtain widely tunable simultaneous second to fifth harmonic generation of conical waves by combining multiple quasi-phase matching interactions in a fully dense square lattice of alternate ferroelectric domains with a poling period Λ~2 μm, which represents the shortest period achieved in 2D bulk optically active LiNbO₃ crystal.


CL-4:IL02  Bioanalytics using Single Plasmonic Nanostructures
J. WIRTH, T. SCHNEIDER, N. JAHR, O. STRANIK, F. GARWE, A. CSAKI, W. FRITZSCHE, Institute of Photonic Technology (IPHT), Jena, Germany

Novel requirements for bioanalytical methods are raised by emerging trends such as personalized medicine or pathogen detection in environment and food. Here, novel tools for diagnostics are needed, to be used outside of dedicated laboratories and with less qualified personnel, and with minimal costs. Plasmonic nanostructures promise to provide sensing capabilities with the potential for ultrasensitive and robust assays in a high parallelization. Upon binding of molecules, the localized surface plasmon resonance (LSPR) of these structure is changed, and can be used as sensoric readout. We present here the use of individual nanostructures (such as gold nanoparticles) for the detection and manipulation of biomolecules (e.g. DNA) based on optical approaches [1]. The presented examples iclude nanoholes in Cr films for easy detection of nanoparticles [2,3], single nanoparticle sensing of DNA [4] using a dark-field setup [5], and manipulation of individual molecules by light based on plasmonic energy conversion [6].
[1] Philosophical Transactions A 369, 3483 (2011).
[2] Int J Env Anal Chem 93, 140 (2013).
[3] J Phys Chem C 117, 7751 (2013)
[4] J Nanopart Res 15, 1531 (2013)
[3] Angew Chem Int Ed 51, 11208 (2012)
[6] Nano Letters 7 (2), 247 (2007).
[7] Nano Letters 11 (4), 1505 (2011).


CL-4:IL03  A New Promising Scintillator Material, Gd2Si2O7:Ce, for Gamma- and Alpha-rays
J.H. KANEKO, Graduate School of Engineering, Hokkaido University, Sapporo, Japan

Gd2Si2O7:Ce (GPS) and related scintillators have been developing more than ten years by Hokkaido University and Hitachi Chemical Ltd. Originally GPS was developed to satisfy the needs of neutron radiography and scattering experiments because of its largest neutron capture cross section for thermal neutrons in all elements and emission of internal electrons after neutron capture of gadolinium. Development of GPS started as an alternative Gd-containing scintillator for neutrons which render compatible a light yield that is higher than that of Gd2SiO5 (GSO) and which provide a counting rate that is higher than that of GOS. The GPS powder synthesized using the solid state reaction not only enabled the measurement of neutrons; its light yield was higher than that of GSO single crystal. A single crystal of GPS was grown using a floating zone (FZ) method. It presented a light yield that was more than three times higher than that of GSO and energy resolution of 5.0% for 662 keV gamma-rays. Additionally, ρZeff4 of GPS is approximately two times larger than NaI:Tl and has neither self-radioactivity nor hygroscopicity.
The possibility of crystal growth of GPS using top-seeded solution growth (TSSG) was found by slow cooling floating zone experiments. In addition, rare-earth pyrosilicates including GPS have polymorphism according to a mean ionic radius of rare-earth elements. The GPS showed orthorhombic structure for cerium concentration of 0–10% and triclinic structure of 10–60%. An orthorhombic GPS grown by TSSG method had 1.4 times light yield larger than that of NaI:Tl and energy resolution of 4.6% was achieved. Moreover, GPS scintillators had excellent scintillation properties under high-temperature environment. Especially, light yield of an orthorhombic GPS was steady from room temperature to 250 Centigrade. Even at 300 Centigrade, light yield of 75% at room temperature was kept by the orthorhombic GPS.


CL-4:IL04  Development of Confined Photonic Structures for Sensing
S. PELLI, D. FARNESI, G.C. RIGHINI, Istituto di Fisica Applicata "Nello Carrara" - CNR, Sesto Fiorentino (Firenze), Italy and Museo Storico della Fisica Centro Studi e Ricerche "Enrico Fermi", Roma, Italy; A. BARUCCI, F. BALDINI, S. BERNESCHI, F. COSI, A. GIANNETTI, G. NUNZI CONTI, S. SORIA, S. TOMBELLI, C. TRONO, Istituto di Fisica Applicata "Nello Carrara" - CNR, Sesto Fiorentino (Firenze), Italy

Sensors based on confined optical structures can offer many advantages in terms of sensitivity, resistance to harsh environments, compatibility with locations where electronic devices pose safety problems. Miniaturised devices can be noninvasively introduced inside the patient body and allow localised medical diagnosis.
This paper will report on the micro- and nano-optical structures developed in our laboratory, namely optical whispering gallery microbubble resonators (WGMR) and silica nanotips.
The former exhibit high quality factor (> 107) resonances, being consequently very sensitive to changes to the resonator structure caused by molecules which bind to the internal functionalised wall of a microbubble. Therefore, by a suitable selective sensing layer implemented on their surface, WGMR can be used as very sensitive sensors for point of care applications.
Silica nanotips are produced by chemical etching of monomode or multimode silica optical fibres. The tip, with dimension down to 40 nm cross-section when bare and 100 nm when metal coated, is able to enter the cells without damaging them. The tip can either carry light inside the cell to locally excite specific molecules, or, when functionalised, can react with them. Detection can be carried out by e.g. a confocal microscope.


Poster Presentations

CL:P01  Fast UV Interconfigurational 5d-4f Luminescence of Pr3+ in Li6Y(BO3)3
M. TREVISANI, F. PICCINELLI, I. CARRASCO RUIZ, M. BETTINELLI, Dept. Biotechnology, University of Verona, Italy

Luminescent materials doped with Pr³⁺ are currently being actively investigated, as they can show allowed 5d-4f optical transitions located in the UV and visible regions. These transitions find numerous applications in important technological fields, such as the development of scintillators [1]. There is a variety of radiation detector applications that require a fast scintillation decay time [2]. This is particularly true for a diagnostic imaging technique such as PET, where a very high time resolution is necessary to suppress random coincidences of incoming γ-rays allowing for high image quality [1]. This has led to the proposed use of the Pr³⁺ ion as activator for advanced scintillators. In fact, compared to Ce³⁺, the 5d-4f emission of Pr³⁺ is characterized by shorter decay times.
In this contribution we investigate the 5d-4f transitions of Pr³⁺ in Li₆Y(BO₃)₃ powders in order to study the possibility of obtaining a potential fast scintillator material. The synthesis and the structural characterization of this material will be described in detail. Luminescence spectra and decay curves measured using synchrotron radiation will be presented and discussed.
[1] C. Ronda, J. Gondek, E. Goirand, T. Jüstel, M. Bettinelli and A. Meijerink, Mater. Res. Soc. Symp. Proc. 1111 (2009) 1111-D08-01.
[2] P.A. Rodnyi, Rad. Measur. 33 (2001) 605.


CL:P02  Preparation and Study of Optical Properties of Transparent Thulium Doped Yttrium-aluminum Garnet Ceramic (Tm:YAG)
A. SIDOROWICZ, Warsaw University of Technology, Warsaw, Poland, Institute of Electronic Materials Technology, Warsaw, Poland; M. NAKIELSKA, A. WAJLER, H. WEGLARZ, Institute of Electronic Materials Technology, Warsaw, Poland; A. OLSZYNA, Warsaw University of Technology, Warsaw, Poland

In this study thulium oxide powder has been prepared by thulium nitrate precipitation with different molar concentration (0.1M, 0.15M, 0.25M) using ammonium hydrogen carbonate as a precipitating agent. The aim of this work was to investigate the relation between precipitation parameters (pH, precipitation temperature) and the properties of thulium oxide nanopowders obtained after precursors calcination. Tm2O3 powders and precursors were characterized by DTA-TG, XRD, SEM, BET techniques and were compared with commercially available powders. The mixtures for reaction sintering of Tm:YAG, containing the powders produced and commercially available, were prepared and consolidated. Finally, Tm:YAG ceramics obtained by reactive sintering (1830oC/6h) using different powders Tm2O3 have been compared in respect to microstructure and transmittance. The resulting Tm:YAG ceramics were characterized by emission spectra and fluorescence dynamics measurement.
The project was financed by the National Science Centre Fund granted based on the decision no. DEC-2011/01/N/ST8/02648.


CL:P04  Synthesis and Optical Characterization of M-a-SiAlON (M=Ca, Ba, Sr) Doped by Europium
D. MICHALIK, T. PAWLIK, M. SOPICKA-LIZER, R. LISIECKI, Silesian University of Technology, Katowice, Poland

Oxynitrides compounds are interesting for white LED industry because more covalent matrix's bonds in comparison to oxides enable to obtain higher color temperature of wLED. The SiAlON's luminescence material doped by rare earth ions with high mechanical and chemical resistance and broad emission band may become an alternative for garnets phosphors. The goal of the study was to investigate influence of parameters of the synthesis on luminescence properties of M-α-Sialon doped with Eu2+ in order to estimate its potential for YAG:Ce replacement in WLEDs. The compound of general formula EuxM1-xSi9,6Al2,4O0,8N15,2, where M=Ca, Ba, Sr, was prepared by the solid state reaction method from the mixture of the relevant oxides, nitrides and carbonates. Synthesis was carried out in the temperature range of 1400-1700 °C for 2-8h in a reduction atmosphere (N2+CO). The structure and morphology of obtained powders were analyzed by XRD and SEM/EDS methods, respectively. Content of nitrogen/oxygen was also analyzed. Optical properties were investigated by excitation, emission and reflection spectra and compared to PL properties of standard YAG:Ce. The obtained specimens show a significant effect of synthesis parameters on the phase composition and intensity of emission of M-α-Sialon:Eu2+ powder.


CL:P06  Influence of m and n Parameters of Ca-α-sialon:Eu Solid Solution on Phosphor's Optical Properties
T. PAWLIK, D. MICHALIK, M. SOPICKA-LIZER, S. SERKOWSKI, Department of Material Science, Silesian University of Technology, Gliwice, Poland

Ca-α-sialon doped by Eu2+ is promising material for white LED phosphor due to strong UV absorption and yellow broad band emission of activator. The general formula of α sialon enables changing matrix composition by altering m (Al-N) and n (Al-O) parameters of cross- substitution. Changes of the neighboring Eu ligands in the host crystal lattice would trigger important modification of the photoluminescence properties because of different crystal field splitting and the energy of the d orbital. The aim of this study was to correlate the matrix solid solution parameters with photoluminescence spectra features.
The specimens of Ca-α-sialon:Eu2+ with m, n parameters in the range of 0.5-2.5 and 0.25-1.75 respectively, were prepared by solid state reaction in the reductive atmosphere of a graphite furnace. The phase composition of the obtained specimens was characterized by XRD with Rietveld refinement, microstructure and morphology by SEM/EDS technique. The photoluminescence spectra (excitation, emission) were also recorded. Results shows that m/n parameters have significant influence on the final optical properties.


CL:P09  Formation and Investigation of the Metallic Particles in the Fluorine Phosphate Glasses
E.V. KOLOBKOVA, V.A. ASEEV, N.V. NIKONOROV, St. Petersburg State University of Information Technologies, Mechanics, and Optics, Saint-Petersburg, Russia

Composite optical materials containing metallic nanoparticles (NP) are promising materials for nonlinear optics and photonics owing to the strong electric fields arising near the surface of NP's due to excitations of surface plasmons, as well as due to possibilities of mutual photon-plasmon transformations. In present work the some specific features of the formation and behavior of silver NPs in fluorine phosphate glasses with varied fluorides concentration are studied by optical absorption and photoluminescence (PL) upon introduction of Ag+ directly into the batch of glassy systems, or via ion exchange. The evolution of the optical properties of silver-doped glasses through thermal treatment and the subsequent formation of NP's are discussed. Silver species in various oxidation and aggregation states (molecular clusters Agn, where n=1, 2, 3 and metallic nanocrystals with AgBr(F) cladding) were observed in a glasses. Influence of the fluorine ions on the growth of nanopartcles is discussed in terms of chemical damping effect and formation complicated structures core/cladding.


CL:P11  Optical Properties of Translucent YAG/YAG-Ce Ceramics
J. PLEWA, T. JÜSTEL, Münster University of Applied Sciences, Steinfurt, Germany

Luminescent screens are widely applied in fluorescent light sources in order to convert the radiation of the primary source into a spectrum suitable for the application aimed at.
While luminescent powders and ceramics show strong scattering and thus solely limited transmission of the incident radiation, translucent ceramics and in particular single crystals show much less or almost no scattering. Light sources based on inorganic InGaN LEDs comprise either a powder layer or a translucent ceramic, whereby the latter has a in general a better homogeneity, thermal conductivity, and thermal stability.
Our experimental work thus focused on the development of translucent YAG:Ce (0.1 - 0.6%) and YAG ceramics, whereby the thickness and scattering properties are optimized to achieve white pcLEDs with an isotropic emission spectrum. The ceramics were made from a YAG/YAG:Ce precursor obtained from a combustion method by uniaxal and isostatic pressing with subsequent sintering at 1600 - 1700 °C.
For the optimization of the package gain and spatial uniformity of the LED spectrum ceramic stacks comprising two ceramic layers, viz. one YAG and one YAG:Ce layer, were fabricated. The reflection, emission, and transmission spectra of these stacks as function of the orientation to the LED chip were recorded.
It was demonstrated that the scattering of blue light in the YAG layer has a strong impact on the overall spectrum achieved by the whole LED package.


CL:P12  Growth Control of Epitaxial CaMoO4 Thin Films by Pulsed Laser Deposition
T. DAZAI, Y. HAMASAKI, S. YASUI, M. ITOH, Tokyo Institute of Technology, Yokohama, Japan

Molybdate materials have attracted attention for solid-state laser and phosphors applications because of their high luminescent efficiency and they may be candidate to Electro Luminescence (EL) device. One of molybdate materials, CaMoO4 (CMO) with scheelite-type structure, has [MoO4]2- units and light-green luminescence could be emitted by their degeneracy structures. It is well known that CMO has been investigated as host materials of phosphors due to superior emission. In the present study, we focused on the smooth surface film of CMO for a display application. CMO films were fabricated on (100) SrTiO3, (100) YSZ, (100) MgAl2O4 substrates by Pulsed Laser Deposition (PLD). Substrate temperature and oxygen pressure under deposition were kept 600 °C and 100 mTorr, respectively. A result of XRD indicated that CMO thin films on (100) SrTiO3, (100) YSZ and (100)MgAl2O4 substrates were grown epitaxially and along [001] direction. In addition, prepared films showed light-green emission of 400 nm to 700 nm wave number under UV lamp irradiation, which was from [MoO4]2- units. Root-mean square (rms) roughness of epitaxial thin films on (100)SrTiO3 (100)YSZ and (100)MgAl2O4 substrates are 2.8, 2.9 and 4.2 nm. This results suggest that CMO thin film could be applied to display device.


CL:P13  Rare Earth Doped Glasses for Displays and Light Generation
U. CALDIÑO¹, M. BETTINELLI², M. FERRARI³, E. PASQUINI^{4, 5}, S. PELLI⁴, A. SPEGHINI^{2, 4}, G.C. RIGHINI^{4, 6}, ¹Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, México, D.F., México; ²Dipartimento di Biotecnologie, Università di Verona, and INSTM, UdR Verona, Verona, Italy; ³IFN - CNR CSMFO Lab., Povo, Trento, Italy; ⁴Istituto di Fisica Applicata Nello Carrara, C.N.R., Sesto Fiorentino (Firenze), Italy; ⁵Dipartimento di Fisica e Astronomia, Università di Firenze, Sesto Fiorentino (Firenze), Italy; ⁶Museo Storico della Fisica e Centro Studi e Ricerche "Enrico Fermi",Roma, Italy

Glasses are very versatile materials, also because of the ease of doping them with various elements and compounds. In particular, rare-earth-doped glasses have greatly contributed to the development of optical amplifiers, lasers, active optical waveguides and white-light-emitting devices. White light emitting diodes (W-LEDs) and colour LEDS obtained by the combination of an UV emitting LED, such as AlGaN-based LED, with a glass phosphor exhibit very interesting properties. They can be efficient for long time and are reliable, safe, energy saving and environmental-friendly: properties which make them quite versatile and attractive for the replacement of conventional incandescent and fluorescent lamps.
In the present contribution we report the luminescence characteristics of zinc-sodium-luminosilicate glasses variously doped, namely either singly doped with Eu3+, Tb3+ or Sm3, or co-doped with Tb3+-Eu3+, Tb3+-Sm3+ and Tb3+-Ce3+. These glasses have also proved to be suitable for ion exchange and therefore for the production of active optical waveguides.


CL:P14  Structural and Optical Characterization of an Elpasolite Matrix: a new type of Opto-thermo Chemical Sensor
L. CORNU, M. GAUDON, P. VEBER, S. PECHEV, O. TOULEMONDE, M. JOSSE, R. DECOURT, V. JUBERA, CNRS, Univ. Bordeaux, ICMCB, UPR 9048, Pessac, France

An increasing demand of sensitive and selective materials is required in several fields as scintillators or sensors. The Elpasolite-type compounds of formula A2BB'X6 (X= halides) belong to the Perovskite family. B and B' cations are distributed in octahedral sites whereas A cation are located in twelve-fold coordinated environment. Among these materials, we have focussed our interest in the Rb/K/In fluorite. Doped with cerium, it possesses the reversible capability under UV irradiation to oxidize and to reduce the trivalent elements leading to a strong contrast of the luminescence properties. Specific temperatures determined through calorific capacity and dielectric constant determination confirmed the existence of two phase transitions at 263 K and 282 K, respectively. The three allotropic forms were determined by XRD measurements performed on single crystal acquisitions. The optical properties showed interesting radiative de-excitation of trivalent cerium unexpectedly located in several environments of this matrix. Magnetic measurements were finally performed to quantify the properties of trivalent cerium stabilized in the host lattice.


CL:P15  Pure Excitonic Emission of ZnO Nanoparticles: Synthesis and Optical Characterization
E. ILIN, C. AYMONIER, S. MARRE, P. MARTIN, R. BROWN, S. LACOMBE, V. JUBERA, ICMCB-CNRS, Pessac Cedex, France

Zinc oxide (ZnO) has been intensively studied for many years because of its potential application in several fields as piezoelectric transducers, optical waveguides, surface acoustic wave devices, transparent conductive oxides, photo-catalysis or sensors. Synthetic route is determining with regard to the optical properties. Strong defects' emissions are generally detected when using soft chemistry syntheses whereas excitonic emission is predominant for well-crystallized materials obtained by chemical vapor deposition, for instance. We have successfully synthesized UV only-emitted nanoparticles using a supercritical synthetic routes. Experimental parameters were optimized to modulate the size of particles and the photocatalytic activity. Growth mechanism was proposed to explain such unexpected pure excitonic emission. Steady state luminescence and decay time measurements leads to the identification of the exciton nature involved in the radiative electron-hole recombination.


CL:P16  Performance of DLC and Si-DLC Films on Ti6Al4V for Aerospace Applications
L.L. FERREIRA¹, P.A. RADI¹, A.S. DA SILVA SOBRINHO¹, L.V. SANTOS², M. MASSI^{1, 3}, ¹Instituto Tecnológico de Aeronáutica, ITA/CTA, São Jose dos Campos - SP, Brazil; ²Universidade do Vale do Paraíba, IP&D/UNIVAP, São Jose dos Campos - SP, Brazil; ³Instituto de Ciência e Tecnologia, ICT/UNIFESP, São Jose dos Campos - SP, Brazil

DLC thin films present interesting properties for aerospace applications as solid lubrificant on mobile parts of satellites, but they suffer degradation by atomic oxygen at orbits of altitude between 100 and 300 km. Various experiments have been performed in order to improve the corrosion resistance of DLC by doping it with several alloy elements. In order to reaches this enhancement DLC and Si-incorporated DLC (Si-DLC) films were deposited on Ti6Al4V substrates by Plasma Enhanced Chemical Vapor Deposition (PECVD) using a DC-pulsed power supply and hexane and hexamethyldisiloxane as carbon, hydrogen and silicon sources. A ball-on-plate tribometer was used to perform tribological tests on untreated and DLC and Si-DLC treated Ti6Al4V surface at air ambient using a Ti6Al4V ball. The tests were performed on reciprocating mode and the track distance was 10 mm. The wear track and ball scratch were inspected using an optical profiler and the lost volumes were calculated. The corrosion tests were conducted in plasma of oxygen using a reactive ion etching (RIE) reactor. The results show that Si-DLC films properties were improved and the corrosion resistance increased more than 100 times compared with DLC films.
Acknowledgments: This work was supported by CNPq-AEB, CAPES and FAPESP.