Analysis of Physics and Chemistry, Volume Lxxxvi
CHAPTER 1 COMPLEX STUDIES ON THE PHOTOLUMINESCENCE OF ER DOPED GES2 GA2S3 GLASSES FOR PHOTONIC APPLICATIONS 1 CHAPTER 2 RARE EARTH ACTIVATED GLASSES IN INTEGRATED OPTICAL DEVICES WITH DIFFERENT GEOMETRIC SHAPES FIBERS PLANAR WAVEGUIDES AND MICROSPHERES 49 CHAPTER 3 PHOTOLUMINESCENCE PROPERTIES OF LAYERED CRYSTALS AND THEIR ORGANIC INORGANIC HYBRID COMPOSITES 93 CHAPTER 4 RECENT PROGRESS IN THE PHOTOLUMINESCENCE PROPERTIES OF COMPOSITES BASED ON CONJUGATED POLYMERS AND CARBON NANOPARTICLES 123 CHAPTER 5 PHOTOLUMINESCENCE OF CARBON BASED NANOMATERIALS FULLERENES CARBON NANOTUBES GRAPHENE GRAPHENE OXIDE GRAPHENE AND CARBON QUANTUM DOTS 146 CHAPTER 6 ADVANCES IN PHOTOLUMINESCENCE PROPERTIES OF COORDINATION POLYMERS 176 CONTENTS CHAPTER 1 COMPLEX STUDIES ON THE PHOTOLUMINESCENCE OF ER DOPED GES2 GA2S3 GLASSES FOR PHOTONIC APPLICATIONS ABSTRACT CHALCOGENIDE GLASSES DOPED WITH RARE EARTH ELEMENTS ARE PARTICULARLY ATTRACTIVE MATERIALS BECAUSE OF THEIR APPLICATIONS IN INTEGRATED PHOTONICS THE CRUCIAL PARAMETERS FOR MANY OPTOELECTRONIC APPLICATIONS REQUIRE AN EXTENSIVE SEARCH FOR MATERIALS WITH IMPROVED CHARACTERISTICS IN PARTICULAR ERBIUM DOPED GLASSES ARE INTENSIVELY STUDIED DUE TO THE ER3 INTRA 4F EMISSION AT THE STANDARD TELECOMMUNICATIONS WAVELENGTH 1540 NM AMONG CHALCOGENIDE GLASSES GE S GA SYSTEM EXHIBITS A LARGER ENHANCED ER3 SOLUBILITY DUE TO THE SPECIFIC STRUCTURAL MODIFICATION INDUCED BY THE INTRODUCTION OF GA INTO THE GE S GLASS THIS CHAPTER IS DEDICATED TO 1 REVIEWING THE STUDIES ON OPTICAL PROPERTIES OF THE GES2 100 X GA2S3 X X 20 25 AND 33 MOL GLASSES DOPED WITH ER2S3 IN A WIDE RANGE FROM 1 8 TO 2 7 MOL BY ABSORPTION AND PHOTOLUMINESCENCE PL SPECTROSCOPY CONSEQUENTLY A SPECIAL ATTENTION HAS BEEN PAID TO THE FEATURES IN ABSORPTION EMISSION LOCAL ORDERING AND THEIR DERIVATIVES AS A FUNCTION OF EXCITATION WAVELENGTH ER3 DOPING LEVEL GA CONTENT AND TEMPERATURE FOR THE GES2 80 GA2S3 20 HOST COMPOSITION THE INFLUENCE OF EXCITATION ON THE STRONGEST PL BAND AT 1540 NM HAS BEEN STUDIED IN MORE DETAIL BY DECONVOLUTION INTO GAUSSIANS RESULTING IN THE CONVERSION OF THE FINE STRUCTURE OF EMISSION BANDS INTO SCHEMATIC STARK LEVELS ENERGY DIAGRAM USUALLY THE EMISSION BANDS ARE EXPLICITLY PRONOUNCED AT LOW TEMPERATURES ACCOMPANIED BY AN ENHANCED NARROWING EFFECT BASIC FEATURES IN THE DEVELOPMENT OF THE EMISSION BANDS OF HEAVILY DOPED SAMPLES HAVE BEEN EVALUATED WITH DECREASING TEMPERATURE FROM 300 K DOWN TO 4 2 K THE CONSIDERABLE ROLE OF THE HOST COMPOSITION ON THE LUMINESCENCE EFFICIENCY IS REGISTERED WITH THE OUTCOME THAT THE GES2 75 GA2S3 25 HOST APPEARS NEARLY OPTIMAL WITH THE DEVELOPMENT OF ALL POSSIBLE EIGHT EMISSION BANDS WHILE AT 33 MOL GA2S3 ONLY THREE BANDS ARE EMERGING WITH CONSIDERABLY LOWERED INTENSITY THIS RESULTS FROM THE NONUNIFORM DISTRIBUTION OF THE DOPING ATOMS BY INCREASING THE NUMBER OF METAL GA GA BONDS BESIDES CSBR ADDITION INTO THE STUDIED GLASSES RESULTS IN AN INCREASE OF THE PL DECAY TIME INDICATING THEIR POTENTIAL SUITABILITY FOR OPTICAL AMPLIFIERS OPERATING IN THE THIRD TELECOMMUNICATION WINDOW AROUND 1540 NM THE UP CONVERTED FLUORESCENCE SPECTRA OF ER DOPED GESGA 90 CSBR 10 GLASSES ARE DISCUSSED AND A SCHEMATIC ENERGY LEVEL DIAGRAM OF THE UP CONVERSION EMISSION IN ER3 IONS IS PROPOSED KEYWORDS CHALCOGENIDE GLASSES OPTICAL PROPERTIES PHOTOLUMINESCENCE RARE EARTH IONS UP CONVERSION FLUORESCENCE 1 INTRODUCTION THE UNIQUE PROPERTIES OF CHALCOGENIDE GLASSES HAVE BEEN STUDIED FOR DECADES PROVIDING APPLICATIONS IN THE ELECTRONICS INDUSTRY IMAGING AND MORE RECENTLY IN PHOTONICS ESPECIALLY THERE HAS BEEN A GROWING RESEARCH INTEREST IN GLASSES DOPED WITH RARE EARTH RE ELEMENTS BECAUSE OF THEIR EXHIBITED ATTRACTIVE PARAMETERS WHICH MAKE THEM KEY MATERIALS FOR PHOTONIC DEVICES SUCH AS LASERS OPTICAL AMPLIFIERS FREQUENCY CONVERTORS AMONG MANY OTHER APPLICATIONS IN THE VISIBLE NEAR AND MID INFRARED 2 ANNALEN DER PHYSIK UND CHEMIE BAND LXXXVI SPECTRAL REGIONS 1 5 IN COMPARISON WITH DIFFERENT GLASSY HOSTS CHALCOGENIDE GLASSES OFFER SEVERAL ADVANTAGES 6 8 THE FIRST ONE IS THE LOW PHONON ENERGY WHICH RESULTS IN THE DECREASE OF NON RADIATIVE RECOMBINATION RATES AND CONSEQUENTLY LEADS TO HIGHER RADIATIVE EFFICIENCIES OF THE OPTICAL TRANSITIONS BETWEEN RE3 ELECTRON ENERGY LEVELS SECONDLY THE SHIFT OF THE LONG WAVELENGTH ABSORPTION EDGE TO LONGER WAVELENGTHS ENSURES ENLARGED TRANSPARENCY IN THE INFRARED REGION THE HIGH REFRACTIVE INDEX OF THESE GLASSES IS RESPONSIBLE FOR THE HIGH SPONTANEOUS EMISSION PROBABILITIES AND THEREFORE TO ENLARGED EMISSION CROSS SECTIONS THE COMBINATION OF LOW PHONON ENERGIES SMALLER OPTICAL BAND GAP AND HIGH REFRACTIVE INDEX LEADS TO HIGHER QUANTUM EFFICIENCIES OF THE RADIATIVE ELECTRON TRANSITIONS BETWEEN THE ENERGY LEVELS OF RE3 IONS IN SULFIDE GLASSES WHICH REMAIN RELATIVELY QUENCHED IN CONVENTIONAL RE DOPED OXIDE AND HALIDE GLASSES 6 BESIDES CHALCOGENIDE GLASSES ARE CHARACTERIZED BY GOOD GLASS FORMING ABILITY HIGH VALUES OF THE GLASS TRANSITION TEMPERATURE AND THERMAL STABILITY 9 12 AMONG CHALCOGENIDE SYSTEMS IT HAS BEEN FOUND THAT GE S GA GLASSES HAVE ALREADY BEEN TESTED AS ATTRACTIVE HOSTS BECAUSE OF THE ER3 INTRA 4F EMISSION AT A TELECOMMUNICATIONS WAVELENGTH OF AROUND 1540 NM 5 8 13 16 CURRENTLY THE 4I13 2 4I15 2 TRANSITION AT 1 5 M IS THE MOST IMPORTANT SINCE ER DOPED OPTICAL FIBERS CAN BE USED AS AMPLIFIERS NAMELY AT THIS WAVELENGTH 5 7 13 THE PREFERRED BONDING STATE OF THE ER3 ION HAS AN INCOMPLETE 4F ELECTRONIC SHELL SURROUNDING FROM THE OUTER WORLD BY CLOSED 5S AND 5P SHELLS AND AS A RESULT SHARP OPTICAL INTRA 4F TRANSITIONS CAN BE REALIZED 13 INTEREST HAS BEEN ALSO FOCUSED ON ERBIUM ABOUT INFRARED TO VISIBLE UP CONVERSION FLUORESCENCE IN PARTICULAR FOR 1 06 M EXCITATION TWO PHONON AND PHONON ASSISTED ENERGY TRANSFER ACCOUNT FOR THE 2H11 2 4I15 2 4S3 2 4I15 2 AND 4F9 2 4I15 2 TRANSITIONS LEADING TO INTENSE GREEN EMISSION AT 530 AND 555 NM AND LESS INTENSE ONE AT 670 NM RESPECTIVELY 17 FOR THE 1 54 M EXCITATION MUCH HIGHER UP CONVERSION HAS BEEN OBTAINED WITH THE RED EMISSION SIGNAL AT 670 NM THAN WITH THE GREEN ONE IT IS CONFIRMED THAT CHOOSING GLASSY HOST WITH THE LOWEST PHONON ENERGY ASSOCIATED WITH NON RADIATIVE LOSS WILL RESULT IN THE MOST EFFICIENT UP CONVERSION 18 BESIDES THE EFFICIENCY OF UP CONVERSION FLUORESCENCE 3 ANNALEN DER PHYSIK UND CHEMIE BAND LXXXVI