Advanced Photonic Applications Research Articles

Strongly polarized quantum-dot-like light emitters embedded in GaAs/GaNAs core/shell nanowires.

Recent developments in fabrication techniques and extensive investigations of the physical properties of III-V semiconductor nanowires (NWs), such as GaAs NWs, have demonstrated their potential for a multitude of advanced electronic and photonics applications. Alloying of GaAs with nitrogen can further enhance the performance and extend the device functionality via intentional defects and heterostructure engineering in GaNAs and GaAs/GaNAs coaxial NWs. In this work, it is shown that incorporation of nitrogen in GaAs NWs leads to formation of three-dimensional confining potentials caused by short-range fluctuations in the nitrogen composition, which are superimposed on long-range alloy disorder. The resulting localized states exhibit a quantum-dot like electronic structure, forming optically active states in the GaNAs shell. By directly correlating the structural and optical properties of individual NWs, it is also shown that formation of the localized states is efficient in pure zinc-blende wires and is further facilitated by structural polymorphism. The light emission from these localized states is found to be spectrally narrow (∼50-130 μeV) and is highly polarized (up to 100%) with the preferable polarization direction orthogonal to the NW axis, suggesting a preferential orientation of the localization potential. These properties of self-assembled nano-emitters embedded in the GaNAs-based nanowire structures may be attractive for potential optoelectronic applications.

A spin-optoelectronic detector for the simultaneous measurement of the degree of circular polarization and intensity of a laser beam

Simultaneous measurement of the degree of circular polarization and intensity of a laser beam is essential in advanced photonic applications. However, it is not feasible with conventional helicity dependent detectors where an additional detector is needed to measure the intensity. Here, we report the development of a spin-optoelectronic detector that can measure the degree of circular polarization and the intensity of a laser beam simultaneously. The principle of operation of device is based on the two independent fundamental phenomena occurring in Au/InP hybrid structures, namely, Inverse Spin Hall Effect (ISHE) and the Photo-Voltaic (PV) Effect. The magnitude of ISHE and PV signals is simultaneously measured across the two pairs of contacts that are made on the top of device. No cross talk is observed between the two detectors made on the same chip. The all-electronic compact device is fast, operates at room temperature, and opens up the possibility of many applications in an integrated optoelectronic platform.

The International Year of Light and Light-based Technologies

I report on the opening ceremony of the International Year of Light and Light-based Technologies 2015 (IYL2015), which took place at the UNESCO headquarters in Paris, France, on 19–20 January 2015. Over the two days, more than 1000 participants from all over the world learned more about the fundamental properties of light and advanced photonics applications, the history of optics and its applications through the centuries, light poverty and light pollution, and light for everyday life, health and research.

Tailoring the optical constants in single-crystal silicon with embedded silver nanostructures for advanced silicon photonics applications

Plasmonic effects associated with metal nanostructures are expected to hold the key to tailoring light emission/propagation and harvesting solar energy in materials including single crystal silicon which remains the backbone in the microelectronics and photovoltaics industries but unfortunately, lacks many functionalities needed for construction of advanced photonic and optoelectronics devices. Currently, silicon plasmonic structures are practically possible only in the configuration with metal nanoparticles or thin film arrays on a silicon surface. This does not enable one to exploit the full potential of plasmonics for optical engineering in silicon, because the plasmonic effects are dominant over a length of ∼50 nm, and the active device region typically lies below the surface much beyond this range. Here, we report on a novel method for the formation of silver nanoparticles embedded within a silicon crystal through metal gettering from a silver thin film deposited at the surface to nanocavities within the Si created by hydrogen ion implantation. The refractive index of the Ag-nanostructured layer is found to be 3–10% lower or higher than that of silicon for wavelengths below or beyond ∼815–900 nm, respectively. Around this wavelength range, the optical extinction values increase by a factor of 10–100 as opposed to the pure silicon case. Increasing the amount of gettered silver leads to an increased extinction as well as a redshift in wavelength position for the resonance. This resonance is attributed to the surface plasmon excitation of the resultant silver nanoparticles in silicon. Additionally, we show that the profiles for optical constants in silicon can be tailored by varying the position and number of nanocavity layers. Such silicon crystals with embedded metal nanostructures would offer novel functional base structures for applications in silicon photonics, optoelectronics, photovoltaics, and plasmonics.

Straightforward synthetic protocol for the introduction of stabilized C nucleophiles in the BODIPY core for advanced sensing and photonic applications.

A straightforward synthetic protocol to directly incorporate stabilized 1,3-dicarbonyl C nucleophiles to the meso position of BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) is reported. Soft nucleophiles generated by deprotonation of 1,3-dicarbonyl derivatives smoothly displace the 8-methylthio group from 8-(methylthio)BODIPY analogues in the presence of Cu(I) thiophenecarboxylate in stoichiometric amounts at room temperature. Seven highly fluorescent new derivatives are prepared with varying yields (20-92%) in short reaction times (5-30 min). The excellent photophysical properties of the new dyes allow focusing on applications never analyzed before for BODIPYs substituted with stabilized C nucleophiles such as pH sensors and lasers in liquid and solid state, highlighting the relevance of the synthetic protocol described in the present work. The attainment of these dyes, with strong UV absorption and highly efficient and stable laser emission in the green spectral region, concerns to one of the greatest challenges in the ongoing development of advanced photonic materials with relevant applications. In fact, organic dyes with emission in the green are the only ones that allow, by frequency-doubling processes, the generation of tunable ultraviolet (250-350 nm) radiation, with ultra-short pulses.

CVD Growth of GeSnSiC Alloys Using Disilane, Digermane, Tin Tetrachloride and Methylsilane

Ge-Sn-Si-C alloys offer a large range of strain engineering which gives the possibility to tailor the material properties for advanced photonic, electronic, photovoltaic and thermoelectric applications. The benefits of Ge-Sn-Si-C alloys are possibilities to obtain a direct-to-indirect transition (for Sn-based alloys) [1], high carrier mobility [2] and low cost process [3]. In this study, Ge1-x-y-zSnxSiyCz layers (0.01≤x≤ 0.24, 0≤y≤0.12 and 0≤z≤0.01) have successfully grown on Ge and Si by using RPCVD technique. It was demonstrated that the quality of epitaxial layers is dependent on the growth parameters, layer thickness and the quality of Ge virtual layer. It was found that a proper strain balance in the matrix during the epitaxy where the Si and Si-C is adjusted carefully compared to Sn flux improves the incorporation of Sn in Ge matrix. This is explained by the compensation of tensile strain induced by Si or Si-C with the compressive strain caused by Sn in order to obtain the minimum energy in Ge matrix. Fig. 1a and 1b show RBS spectra of two GeSnSi samples when the first one has a constant Si flux whereas the sample in Fig. 1b has a graded Si flux within GeSnSi layer. The Sn incorporation improved from 3% to 24% when Si flux was graded.Incorporation of P and B in GeSnSiC matrix has been studied and the effect of dopant concentrations on Sn content has been investigated. A low boron concentration in range of 1017 cm-3 could be incorporated in the epi-layers whereas P-doping in range of 1019 cm-3could be achieved. All Ge1-x-ySnxSiyCz layers were grown at 280-330 °C at 20 torr in a RPCVD reactor. The gas precursors were Si3H8, Ge2H6, 1% B2H6 in H2, 5% PH3 in H2, and SnCl4as Si, Ge, B, P and Sn sources, respectively. The strain in the epi-layers was measured by high-resolution x-ray reciprocal lattice maps (HRRLMs). Transmission electron microscopy (TEM) was applied to detect the defects in the epi-layers and to observe the interfacial quality. The Sn, Si and C content in the samples was measured by Rutherford backscattering spectrometry (RBS) and HRRLMs. The atomic dopant concentration in the epi-layers was measured by secondary ion mass spectrometry (SIMS). Four-probe measurements were done to determine the resistivity of the doped layers.The quality of carrier and reactant gases in terms of oxygen and water vapor was investigated by residual gas analyzer (RGA). The RGA instrument was connected to the exhaust gas output and was situated in 20 mm distance from the reactant gas chamber. A RGA spectrum reveals any absorption or desorption of molecules with accuracy of ppt range. The results showed that the level of oxygen during epitaxy was as low as 10 ppb and the contamination concetration was found as low as 1017 cm-3. This low oxygen level during epitxy is due to the high purity of trisilane, digermane and tetrachloride precursors as well as the hydrogen carrier gas. Acknowledgment The Swedish Research Council (VR) is greatly acknowledged for supporting this work.

Laser sources for microwave to millimeter-wave applications [Invited

We present several laser sources dedicated to advanced microwave photonic applications. A quantum-dash mode-locked laser delivering a high-power, ultra-stable pulse train is first described. We measure a linewidth below 300 kHz at a 4.3 GHz repetition rate for an output power above 300 mW and a pulse duration of 1.1 ps after compression, making this source ideal for microwave signal sampling applications. A widely tunable (5–110 GHz), monolithic millimeter-wave transceiver based on the integration of two semiconductor distributed feedback lasers, four amplifiers, and two high-speed uni-traveling carrier photodiodes is then presented, together with its application to the wireless transmission of data at 200 Mb/s. A frequency-agile laser source dedicated to microwave signal processing is then described. It delivers arbitrary frequency sweeps over 20 GHz with high precision and high speed (above 400 GHz/ms). Finally, we report on a low-noise (below 1 kHz linewidth), solid-state, dual-frequency laser source. It allows independent tuning of the two frequencies in the perspective of the implementation of a tunable optoelectronic oscillator based on a high-Q optical resonator.

A new tetrakis β-diketone ligand for NIR emitting LnIII ions: luminescent doped PMMA films and flexible resins for advanced photonic applications

A new antenna molecule containing four benzoyltrifluoroacetone (BTFA) moieties anchored to a single carbon atom and connected through four flexible methoxy groups, namely 1,1′-(4,4′-(2,2-bis((4-(4,4,4-trifluoro-3-oxobutanoyl)phenoxy)methyl) propane-1,3-diyl)bis(oxy)bis(4,1-phenylene))bis(4,4,4-trifluorobutane-1,3-dione) [H4L], has been designed and synthesized. Using this ligand, a series of homo- and hetero-metallic LnIII complexes of general formula [LnL]NBu4 (where Ln = Sm (1), Gd (2), Er (3), Yb (4), Er0.5Yb0.5 (5), Er0.5Gd0.5 (6), Yb0.5Gd0.5 (7) and NBu4 = tetrabutyl ammonium) have been isolated. All these complexes have high molar absorption coefficients (>40 000 M−1 cm−1 around 330 nm in DMF) and display strong visible (SmIII) and/or, NIR (SmIII, ErIII, YbIII) luminescence in solid state and in DMF solution upon irradiation at the ligand-centred bands in the range 250–400 nm. Furthermore, these complexes have been doped into PMMA matrices yielding highly luminescent, photo-stable films and flexible resins made of fibres with average diameter 300–400 nm. Photoluminescence studies show that the newly designed ligand is an adequate sensitizer for SmIII, YbIII and ErIII luminescence. The emission quantum yields and the luminescence lifetimes at room-temperature are 3.4 ± 0.5% and 79.1 ± 1 μs for SmIII and 2.6 ± 0.4% and 12.1 ± 0.1 μs for YbIII in solid state. Furthermore the overall quantum yields and lifetime measurements for the mixed metallic complex show that YbIII → ErIII energy transfer occurs resulting in enhanced ErIII emission.

Supramolecular Chiral Structures: Smart Polymer Organization Guided by 2D Polarization Light Patterns

AbstractChiral periodic structures and photonic crystals have attracted a great deal of interest due to their applications in advanced photonics. As a consequence, the design and the fabrication of periodic microstructures in photosensitive materials have been widely investigated. Many achievements in the fabrication of such devices have been made over the last decade, but most of the established methods are still restricted to light intensity distribution with different structural shapes and minor attention has been devoted to exploit the vectorial nature of the light coupled with the response of polarization sensitive materials. Here, supramolecular chiral structuring in an amorphous azo‐polymer is demonstrated, coupling the strong and diversified photoresponse of the material with the holographic recording of 2D polarization patterns. The smart polymer organization guided by the complex light field induces periodic chiral microstructures, with spiral‐ or ribbon‐like shape and identical or opposite helicity, characterized by high stability and complete reconfigurability. The holographic structures are theoretically described by means of the Jones matrix method and experimentally investigated, confirming the simultaneous presence of both linear and circular photoinduced anisotropies. These results prove an alternative approach to design a new class of materials with periodic chiral arrangement.

Luminescent Lanthanide Complexes for Advanced Photonics Applications

Luminescent lanthanide complexes have been overviewed for advanced photonics applications. Lanthanide(III) ions (<TEX>$Ln^{3+}$</TEX>) were encapsulated by the luminescent ligands such as metalloporphyrins, naphthalenes, anthracene, push-pull diketone derivatives and boron dipyrromethene(bodipy). The energy levels of the luminescent ligands were tailored to maintain the effective energy transfer process from luminescent ligands to <TEX>$Ln^{3+}$</TEX> ions for getting a higher optical amplification gain. Also, key parameters for emission enhancement and efficient energy transfer pathways for the sensitization of <TEX>$Ln^{3+}$</TEX> ions by luminescent ligands were investigated. Furthermore, to enhance the optophysical properties of novel luminescent <TEX>$Ln^{3+}$</TEX> complexes, aryl ether-functionalized dendrons as photon antennas have been incorporated into luminescent <TEX>$Ln^{3+}$</TEX> complexes, yielding novel <TEX>$Ln^{3+}$</TEX>-cored dendrimer complex such as metalloporphyrins, naphthalenes, and anthracenes bearing the Fr<TEX>$\acute{e}$</TEX>chet aryl-ether dendrons, namely, (<TEX>$Er^{3+}-[Gn-Pt-Por]_3$</TEX> (terpy), <TEX>$Er^{3+}-[Gn-Naph]_3$</TEX>(terpy) and <TEX>$Er^{3+}-[Gn-An]_3$</TEX>(terpy)). These complexs showed much stronger near-IR emission bands at 1530 nm, originated from the 4f-4f electronic transition of the first excited state (<TEX>$^4I_{13/2}$</TEX>) to the ground state (<TEX>$^4I_{15/2}$</TEX>) of the partially filled 4f shell. A significant decrease in the fluorescence of metalloporphyrins, naphthalenes and anthracene ligand were accompanied by a strong increase in the near IR emission of the <TEX>$Ln^{3+}$</TEX> ions. The near IR emission intensities of <TEX>$Ln^{3+}$</TEX> ions in the lanthanide(III)-encapsulated dendrimer complexes were dramatically enhanced with increasing the generation number (n) of dendrons, due to the site-isolation and the light-harvesting(LH) effects. Furthermore, it was first attempted to distinguish between the site-isolation and the light-harvesting effects in the present complexes. In this review, synthesis and photophysical studies of inert and stable luminescent <TEX>$Ln^{3+}$</TEX> complexes will be dealt for the advanced photonics applications. Also, the review will include the exploratory investigation of the key parameters for emission enhancement and the effective energy transfer pathways from luminescent ligands to <TEX>$Ln^{3+}$</TEX> ions with <TEX>$Ln^{3+}$</TEX>-chelated prototype complexes.

Monolithic, Hierarchical Surface Reliefs by Holographic Photofluidization of Azopolymer Arrays: Direct Visualization of Polymeric Flows

AbstractHierarchically ordered, monolithic surface reliefs have attracted a great deal of interest due to their applications in advanced photonics and interface sciences. While many impressive achievements in fabrication of such surface reliefs have been made over the last decade, all established methods are still restricted by a number of factors, such as limited control of structural features, inherently induced structural defects, impractically low throughput, and technical barriers caused by mechanical contact. Herein, a deterministic and scalable fabrication of hierarchically ordered, monolithic surface reliefs by holographic photofluidization of azopolymer line arrays is demonstrated. In particular, it is shown that the structural features of monolithic surface reliefs including shapes and modulation heights can be deterministically tunable by adjusting the polarization and irradiation time of the holographic interference pattern. Moreover, by a direct visualization of azopolymeric flow according to the light polarization, a long‐standing question about the origin of surface‐relief‐grating formation on azopolymer film is addressed in terms of polymeric flows. Finally, as proof of concept for the practical application of the obtained hierarchical surface reliefs, dependence of wetting properties on modulating height is demonstrated.

Eighth International Workshop on Epitaxial Semiconductors on Patterned Substrates and Novel Index Surfaces

This year, Italy hosted the VIII ESPS-NIS workshop. It was organized by the L-NESS Inter-University Laboratory (Politecnico di Milano and Universita di Milano Bicocca) in Como (Italy) under the auspices of Prof. Leo Miglio. The program of 10 invited speakers, 30 contributed and numerous posters covered a wide range of topics, all connected with the study of substrate patterning and high index substrate influence on the growth and the control of semiconductor nanostructures. Presentation was given on novel patterning techniques, both top-down and bottom-up, and the effect of patterning on self-organized dots and wires. In particular, wires have recently attracted a wide attention, since they are important both in fundamental physics and in advanced electronics and photonics applications. New concept bottom-up patterning techniques, like metallic droplet nano-drilling and droplet epitaxy local artificial substrates, were presented. Epitaxy of graphene on patterned substrates was also a topic of the workshop. The possibility of controlling, by substrate patterning, the nucleation site and the strain relaxation of self-organized Stranski–Krastanow dots in Ge/Si and InAs/GaAs systems has motivated a strong effort as evidenced by the number and the quality of the contribution presented. Some very interesting features involve strain engineering, position and size control, defectivity reduction. In addition, patterned substrates epitaxy inevitably involves growth on high index planes, which stimulated the understanding the effects of epitaxial growth of semiconductors on non-(100) surfaces. The ESPS-NIS meeting discussed all these aspects, which include material growth, characterization, theory and device topics related to patterned substrates, novel index substrates and low dimensional structures. Once more the meeting achieved its aim of being a forum for lively discussion of up to date work, allowing the interaction of specialist of different fields of semiconductor science and technology put together by the common interest in the effects of patterning and surface orientation on nanostructure fabrication. The vast potential of interrelation of nanotechnology, patterning and surface science was highlighted. The organizing committee would like to thank the speakers for their considerable efforts in making this workshop a success. A fundamental role in the organization was also played by the personnel of the the Centro di Cultura Scientifica Alessandro Volta of Como. Finally, special thanks are due to the University of Milano Bicocca and the Politecnico di Milano, Polo di Como whose sponsorship made this international workshop possible. ESPS-NIS VIII Conference Chair: Prof. Leo Miglio (University of Milano Bicocca) Program committee: Chair: Prof. Stefano Sanguinetti (University of Milano Bicocca) Dr Francesco Montalenti (University of Milano Bicocca) Dr Roman Sordan (Politecnico di Milano) Dr Daniel Chrastina (Politecnico di Milano) Local organizing Committee Dr Giovanni Isella (Politecnico di Milano) Dr Emiliano Bonera (University of Milano Bicocca) Dr Monica Bollani (CNR—Milano) Dr Alessandra Cazzaniga (Centro Volta)

Development of Simulation Tools to Study Optical Properties of One-Dimensional Photonic Crystals

Photonic crystals (PCs) have become a key subject due to its enormous applications in advanced photonics. The simulation tools have been developed using MATLAB software to analyze the optical and physical parameters. Significant variation in refractive index contrast from 1.65 to 2.5 has been observed which remarkably affects to the forbidden bandwidth. The bandwidth of photonic bandgap and reflectance shows great dependency on frequency and incidence angle of light. The broad region of reflectance bands demonstrates that the light propagation is strictly prohibited in these regions. The peak value of effective index is found to be 42.32 for its corresponding value of group velocity nearly equals to zero. The group velocity approaches to '0' at frequency 0.2894 which indicates the initial point of a forbidden bandgap.

Two‐Dimensional Electronic Conjugation: Statics and Dynamics at Structural Domains Beyond Molecular Wires

Chemical architectures supporting a high degree of electronic conjugation serve as important functional components in devices and materials for advanced electronic and photonic applications. Increasing the spatial dimensionality of such constructs can fundamentally modify their optoelectronic properties and significantly alter intra- and intermolecular interactions that are crucial for understanding and controlling charge/energy-transfer processes. In this article, emerging design principles in the construction of well-defined conjugated platforms beyond molecular wires are highlighted. Both covalent and noncovalent approaches can be strategically employed to position one-dimensional (1D) substructures in a spatially well-defined manner in order to enhance both structural and functional complexity in a two-dimensional (2D) setting. A predictable and controllable switching mechanism can be designed and implemented with mobile 2D electronic conjugation that operates by correlated motions of inherently rigid 1D subunits. This emerging "dynamic" approach complements and challenges the prevailing "static" paradigm of conjugated chemical architectures.

Synthesis and Photophysical Properties of Luminescent Lanthanide Complexes Based on Dansyl-N-Methyl-Aminobenzoic Acid for Advanced Photonics Applications

ABSTRACT Novel luminescent Ln(III)-chelated complexes based on dansyl-N-methyl-aminobenzoic acid exhibited the strong near IR emission bands of the characteristic 4I13/2 → 4I15/2 transition of Er(III) ion around 1530 nm and the characteristic 4F3/2 → 4F9/2, 4F3/2 → 4F11/2 and 4F3/2 → 4F13/2 transitions of Nd(III) ion around 880, 1060 and 1330 nm. Their photoluminescence intensity depends on the degree of the spectral overlap between the emission band of the ligand and the absorption band of lanthanide(III) ion. The radiative life times of Er(III) and Nd(III) ions in the lanthanide(III) complex films were estimated to be 1.6 and 1.2 μs, respectively.

LANTHANIDE(III)-CORED SUPRAMOLECULAR COMPLEXES WITH LIGHT-HARVESTING DENDRITIC ARRAYS FOR ADVANCED PHOTONICS APPLICATIONS

We have designed and developed novel lanthanide(III)-cored supramolecular systems with light-harvesting dendritic arrays for advanced photonics applications such as planar waveguide amplifiers, plastic lasers, and light-emitting diodes. The supramolecular ligands, such as naphthalenes and metalloporphyrins, were specially designed and synthesized in order to provide enough coordination sites to form stable lanthanide(III)-chelated complexes. The energy levels of the supramolecular ligands were tailored to maintain the effective energy transfer process from supramolecular ligands to lanthanide(III) ions for getting a higher optical amplification gain. Also, efficient energy transfer pathways for the sensitization of lanthanide ions by supramolecular ligands were investigated, for the first time to the best our knowledge. Furthermore, to enhance the optophysical properties of novel supramolecular systems, aryl ether-functionalized dendrons as photon antennas have been incorporated into lanthanide-cored supramolecular systems, yielding novel lanthanide-cored dendritic materials with efficient site-isolation effect.

3‐D Molecular Assembly of Function in Titania‐Based Composite Material Systems

AbstractFor Abstract see ChemInform Abstract in Full Text.

3-D Molecular Assembly of Function in Titania-Based Composite Material Systems

Various examples of composite titania-based nanostructured materials exhibiting cooperative functionalities between different active components are presented. The fabrication of these integrated composite materials is based on one-pot supramolecular templating techniques combined with acidic sol-gel chemistry. The defined 3-D nanoscale organization and integration of various functional components results in advanced optoelectronic and photonic applications such as visible light sensitization of mesoporous titania photocatalysts with cadmium sulfide nanocrystals acting as sensitizing integral part of the mesopore wall structure, narrow bandwidth emission from rare earth ion activated nanocrystalline mesoporous titania films, and mirrorless lasing in dye-doped hybrid organic/inorganic mesostructured titania waveguides.

Recent Progress in Luminescent Lanthanide Complexes for Advanced Photonics Applications

We have designed and developed novel luminescent lanthanide complexes for advanced photonics applications. Lanthanide(III) ions (Ln<TEX>$^{3+}$</TEX>) were encapsulated by the luminescent ligands such as metalloporphyrins and naphthalenes. The energy levels of the luminescent ligands were tailored to maintain the effective energy transfer process from luminescent ligands to Ln<TEX>$^{3+}$</TEX> ions for getting a higher optical amplification gain. Also, key parameters for emission enhancement and efficient energy transfer pathways for the sensitization of Ln<TEX>$^{3+}$</TEX> ions by luminescent ligands were investigated. Furthermore, to enhance the optophysical properties of novel luminescent Ln<TEX>$^{3+}$</TEX> complexes, aryl ether-functionalized dendrons as photon antennas have been incorporated into luminescent Ln<TEX>$^{3+}$</TEX> complexes, yielding novel Ln(III)-cored dendrimer complex. The novel Ln(III)-cored dendrimer complex has much higher PL intensity than the corresponding simple complex, due to the efficient site-isolation effect. In this article, we will deal with recent progress in the synthesis and photophysical studies of inert and stable luminescent Ln<TEX>$^{3+}$</TEX> complexes for advanced photonics applications. Also, our review will include the exploratory investigation of the key parameters for emission enhancement and the effective energy transfer pathways from luminescent ligands to Ln<TEX>$^{3+}$</TEX> ions with Ln(III)-chelated prototype complexes.

Synthesis and Photophysical Properties of Luminescent Lanthanide Complexes Based on Coumarin-3-carboxylic Acid for Advanced Photonic Applications

Center for Smart Light-Harvesting Materials and Department of Polymer Science & Engineering,Hannam University, 133 Ojung-dong, Daeduck-gu, Daejeon 306-791, KoreaReceived September 4, 2003Key Words : Coumarin-3-carboxylic acid, Luminescent lanthanide complexes, Photophysical properties,Planar waveguide amplifliers, Light-emitting diodesRecently, luminescent lanthanide complexes have attractedmuch attention because of their academic interests as well aspotential utility of this technology in a wide variety ofphotonic applications such as planar waveguide amplifiers,plastic lasers, and light-emitting diodes.