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Microcavities
Kinds of Microcavities Selected AbstractsMicrocavity modified spontaneous emission of single quantum dotsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 8 2007G. S. Solomon Abstract We summarize our earlier research showing how the radiative properties of an individual InAs quantum dot exciton state can be altered by their spatial and spectral position with respect to a discrete semiconductor microcavity mode. The InAs quantum dot is formed epitaxially in GaAs, and the microcavity is processed from a one-wavelength distributed Bragg reflector planar microcavity of GaAs and AlAs to form a sub-micrometer diameter pillar. Two states are tuned through a discrete cavity mode through sample temperature changes and show a spontaneous emission enhancement of 4. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Macroporous Silicon Microcavities for Macromolecule Detection,ADVANCED FUNCTIONAL MATERIALS, Issue 11 2005H. Ouyang Abstract Macroporous silicon microcavities for detection of large biological molecules have been fabricated from highly doped n-type silicon. Well-defined controllable pore sizes up to 120,nm have been obtained by systematically optimizing the etching parameters. The dependence of the sensor sensitivity on pore size is discussed. Excellent infiltration inside these macroporous silicon microcavities is demonstrated using 60,nm diameter latex spheres and rabbit IgG (150,kDa; 1Da,=,1,g,mol,1). The sensing performance of the device is tested using a biotin/streptavidin couple, and protein concentration down to 1,2,,M (equivalent to 0.3,ng,mm,2) could be detected. Simulations show that the sensitivity of the technique is currently approximately 1,2,% of a protein monolayer. [source] Spontaneous Emission Control in Micropillar Cavities Containing a Fluorescent Molecular Dye,ADVANCED MATERIALS, Issue 6 2006M. Adawi The fabrication of micropillar microcavities containing a fluorescent organic dye is reported. Scanning near-field optical microscopy of the luminescence from such structures (see figure and cover) confirms that a significant increase in radiative rate occurs as a result of the reduced optical-mode volume. Such structures may eventually permit efficient single-photon light sources operating at room temperature to be developed for quantum-cryptography and quantum-computing applications. [source] Redox-Tunable Defects in Colloidal Photonic Crystals,ADVANCED MATERIALS, Issue 20 2005F. Fleischhaker Reversible tuning of an intragap transmitting state induced by redox cycling is accomplished using a redox-active polyelectrolyte multilayer planar defect embedded in a colloidal photonic crystal (CPC). The wavelength position of the defect state can be changed by changing the oxidation state of the ferrocene moieties in the polymer backbone (see Figure). This could find applications in electrochemically tunable microcavities and CPC-based laser sources. [source] Development of transient head cavities during early organogenesis of the Nile Crocodile (Crocodylus niloticus)JOURNAL OF MORPHOLOGY, Issue 9 2009Martin Kundrát Abstract Three consecutive pairs of head cavities (premandibular, mandibular, and hyoid) found in elasmobranchs have been considered as remnants of preotic ,head' somites,serial homologues of the myotomic compartments of trunk somites that give rise to the extraoccular musculature. Here, we study a more derived vertebrate, and show that cavitation is more complex in the head of Crocodylus niloticus, than just the occurrence of three pairs of cavities. Apart from the premandibular cavities, paired satellite microcavities, and unpaired extrapremandibular microcavities are recognized in the prechordal region as well. We observed that several developmental phenomena occur at the same time as the formation of the head cavities (premandibular, satellite, extrapremandibular, mandibular, and hyoid) appear temporarily in the crocodile embryo. These are 1) rapid growth of the optic stalk and inflation of the optic vesicle; 2) release of the intimate topographical relationships between the neural tube, notochord and oral gut; 3) tendency of the prechordal mesenchyme to follow the curvature of the forebrain; and 4) proliferation of the prechordal mesenchyme. On the basis of volumetric characters, only the hyoid cavity and hyoid condensation is comparable to the trunk somitocoel and somite, respectively. J. Morphol. 2009. © 2009 Wiley-Liss, Inc. [source] Construction of PbZr0.4Ti0.6O3 - and Ba0.9Sr0.1TiO3 -Based Optical Microcavities by Chemical Solution DepositionJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2009Jing L. Shang Herein we report on a simple, low cost, and feasible route for the construction of PbZr0.4Ti0.6O3 (PZT)- or Ba0.9Sr0.1TiO3 (BST)-based optical microcavities using a single chemical solution containing polymer polyvinylpyrrolidone. The obtained multilayer systems not only exhibit good ferroelectric performance, but also display well-defined resonant modes with a quality factor of no <66. Compared with PZT microcavities, the optical properties of the BST microcavities appear to be superior. [source] Unusual preservation of crustaceans and microbial colonies in a vadose zone, northwest MoroccoLETHAIA, Issue 1 2003MICHAEL J. DUANE Exceptional fossil preservation is observed in self-sealing microcavities in limestones where lichens, cyanobacteria and fungi together entombed themselves and organic walled microfossils, crustaceans and their eggs. Preservation has been enabled by calcite coating, lining and impregnation of the exoskeleton of the crustaceans, which had a high original calcium content and acted as a nucleus for precipitation. The good preservation was facilitated by the microcavities, the surrounding limestone, the seasonality and rapidity of precipitation, the microbial colonies living on the specimens, and the fluxing of vadose waters through the karst. The microbes and the crustaceans probably became trapped by the very high rate of calcite precipitation promoted within the cavities. Entrapment in mucous-secreting mats of cyanobacteria and fungi preceded the destruction of some of the soft parts of the crustaceans. By the time the mats and the incorporated biota were sealed into the cavities in the limestone, the mucosic mats and their bacterial communities had mediated production of a range of calcite cements promoting preservation of the refractory tissues. This process has important implications for cementation studies in arid zones (and especially in the Martian subsurface), since a range of microbes are involved in progressive biomineralization leading to fossilization within a perched, vadose karst. [source] Low intensity directional switching of light in semiconductor microcavitiesPHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 1 2009Stefan Schumacher Abstract Recently it was demonstrated that in atomic vapors weak control beams can manipulate (or switch) the propagation direction of strong light beams [Dawes et al., Science 308, 672 (2005)]. As a semiconductor analog of such all-optical switching, we present a proposal for similar manipulation and switching in planar semiconductor microcavities. Using a microscopic many-particle theory, we investigate the spatio-temporal dynamics of four-wave mixing signals and related instabilities in these systems. Even though the underlying physical processes are different from atomic systems, we find that microcavities allow for reversible directional manipulation of light. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Whispering gallery modes in silicon nanocrystal coated microcavitiesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2009P. Bianucci Abstract We present photoluminescence studies of silicon-nanocrystal (Si-NC) coated microcavities. The particular geometries studied are hollow fibers where there is a Si-NC coating in the inner surface and regular optical fibers and glass microspheres where the coating is on the outside surface. The coatings were prepared using an inexpensive and straightforward solution-based process that yields a high-quality film. The measured photoluminescence spectra from the resonators show high Q -factor (between 1200 and 2800) resonant modes that correspond with the whispering gallery modes expected from the confinement geometries. The presence of these modes is also an indication that the emission of the Si-NCs is coupled to the cavity. The combination of Si-NCs and optical microcavities with strong confinement has promising potential for applications like sensing, optical communications and may be a possible route toward a Si-NC laser. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Micropore modification in InPPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 11 2008D. Nohavica Abstract The structural features and optical properties of microporous InP substrates used for epitaxial overgrowth of thin films have been investigated. Both crystalographically oriented (CO) and current line oriented (CLO) pore networks were created by electrochemical dissolution. Heat treatment of the InP pores converted them into microcavities maintaining the same crystallographic direction. The effect of phosphorus vapour pressure was proved to be crucial for the microcavity formation, since it influences the mass transport during heat treatment. Electron microscopy and photoluminescence experiments revealed the absence of significant extended defects, both after the pore and cavities formation. The capability of improved structural quality homo- and hetero-epitaxial overgrown films on the porous InP, was also demonstrated. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Crack free monolithic nitride vertical-cavity surface-emitting laser structures and pillar microcavitiesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2006Henning Lohmeyer Abstract We report on the successful fabrication and optical investigation of monolithicly grown GaN based vertical-cavity surface-emitting laser structures featuring quality factors of 250. Short-period AlN/InGaN superlattices are used for the low-index layers of the distributed Bragg reflectors. Pillar microcavities are realized by focused-ion-beam etching. Micro-photoluminescence measurements reveal the longitudinal and transversal mode spectra of the cavities in good agreement with theoretical calculations based on a vectorial transfer matrix method. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Development of CdSSe/CdS VCSELs for Application to Laser Cathode Ray TubesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 4 2004K. P. O'Donnell Abstract This report summarises recent progress towards the realisation of Laser Cathode Ray Tube (LCRT) devices on the basis of II,VI semiconductors. Although such devices were demonstrated over 30 years ago, using bulk crystalline materials as the active media, practical lasers that operate at room temperature for extended periods of time are not yet readily available. We aim to overcome this roadblock by reducing the threshold power densities of working lasers. By embedding heterostructures, grown using metalorganic vapour phase epitaxy (MOVPE), within all-dielectric microcavities, the necessary threshold reductions can be made. The construction and testing of an exemplar device, based upon CdSSe/CdS (hex) multiple quantum wells, is described. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Photophysics of J-aggregate microcavitiesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 6 2008P. Michetti Abstract We have developed a model in order to account for the photo-excitation dynamics of J-aggregate films and strongly coupled J-aggregate microcavities. The J-aggregates are described as a disordered Frenkel exciton system in which relaxation occurs due to the presence of a thermal bath of molecular vibrations. The link between the J-aggregate film and the microcavities is obtained introducing a model polariton wavefunction mixing cavity photon modes and J-aggregate superradiant excitons. With the same approach we have calculated both absorption and luminescence spectra for the J-aggregate film and the photoluminescence of strongly coupled organic microcavities. The model is able to explain the organic microcavities fast relaxation dynamics and polariton luminescence following non resonant pumping starting from the excitonic properties of the optically active layer. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] On the way to InGaN quantum dots embedded into monolithic nitride cavitiesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 6 2007K. Sebald Abstract We present photoluminescence measurements on single InGaN quantum dots (QDs) grown by metalorganic vapor phase epitaxy, and on monolithicly grown GaN-based quantum well airpost pillar microcavities. The observed sharp emission lines of the quantum dots are characterized by excitation density dependent measurements. The photoluminescence of individual quantum dots can easily be detected for temperatures up to 150 K. The micro-photoluminescence measurements on microcavities reveal three-dimensional confined optical modes which are not seen in the luminescence of the simply planar cavity. The realization of rather temperature stable QDs as well as of nitride based microcavity samples are promising with respect to the intended implementation of QD layers into microcavities. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Non-linear dynamical effects in semiconductor microcavitiesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11 2005J. L. Staehli Abstract An investigation of the parametric amplification and its coherent control in a semiconductor microcavity is presented. The time and angle resolved pump and probe experiments show that several picoseconds after pumping the polaritons are still coherent and parametric scattering is still going on. The experimental data concerning the time integrated measurements are in qualitative agreement with the numerical data obtained from a relatively simple theoretical model based on three polarisation components, pump, probe, and idler. As for the dynamics of parametric amplification in real time, the measurements reveal that often stimulation is considerably delayed with respect to the arrival of pump and probe. Even though the observed dynamics is complex, our simple theoretical model permits to reproduce several of the experimental features. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Polariton correlation in microcavities produced by parametric scatteringPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11 2005Wolfgang Langbein Abstract The spontaneous and self-stimulated parametric emission from a semiconductor microcavity after resonant pulsed excitation is measured. The emission of the lower polariton branch is resolved in two-dimensional momentum space, using either time-resolved or spectrally resolved detection. The polariton,polariton scattering dynamics is generally in good agreement with the theory using the nonlinearity due to the excitonic part and the dispersion due to the photonic part of the polariton. The peculiar figure-8 shaped distribution in momentum space of the final states of the parametric scattering is observed. Renormalization of the dispersion due to the bound biexciton state is found to influence the final state distribution. Using two pump directions the shape of the final state distribution can be changed to a peanut or oval for the mixed parametric processes. In this dual pump configuration, we find that polaritons in two distinct idler-modes interfere if and only if they share the same signal-mode, showing the existence of polariton pair correlations that store the "which-way" information. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Spin dynamics of exciton polaritons in microcavitiesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11 2005I. A. Shelykh Abstract In this chapter we address a complex set of optical phenomena linked to the spin dynamics of exciton polaritons in semiconductor microcavities. When optically created, polaritons inherit the spin and dipole moment from the exciting light. Their state can be fully characterized by a so-called "pseudospin" accounting for both spin and dipole moment orientation. However, from the very beginning of their life in a microcavity, polaritons start changing their pseudospin state under effect of effective magnetic fields of different nature and due to scattering with acoustic phonons, defects, and other polaritons. This makes pseudospin dynamics of exciton polaritons rich and complex. It manifests itself in non-trivial changes in polarization of light emitted by the cavity versus time, pumping energy, pumping intensity and polarization. During the first years of theoretical research on exciton-polariton relaxation the polarization has been simply neglected. Later it has been understood that the energy and momentum-relaxation of exciton polaritons are spin-dependent. It is typically the case in the regime of stimulated scattering when the spin polarizations of initial and final polariton state have a huge effect on the scattering rate between these states. It appeared that critical conditions for polariton Bose-condensation are also polarization-dependent. In particular, the stimulation threshold (i.e. the pumping power needed to have a population exceeding 1 at the ground state of the lower polariton branch) has been experimentally shown to be lower under linear than under circular pumping. These experimental observations have stimulated the theoretical research toward understanding of mutually dependent polarization- and energy-relaxation mechanisms in microcavities. The authors of this chapter have been working on theoretical description of different specific effects of polariton spin-dynamics in microcavities for years. Here we attempted to put together all fragments and to formulate a general approach to the problem that would allow then to consider a variety of particular cases. We start from reminding the main spin-relaxation mechanisms known for free carriers and excitons. We then overview the most essential experimental results in this field before to present our original formalism which allowed us to interpret the key experimental findings. We are going to discuss only the strong coupling regime leaving aside all polarization effects in VCSELs. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] InAs/InP quantum dot photonic crystal microcavitiesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2006Simon Frédérick Abstract We examine the optical mode structure of two-dimensional, photonic crystal microcavities based on triple missing hole defects in hexagonal symmetry, etched air-hole, suspended InP membranes. Polarisation dependent photoluminescence from InAs/InP quantum dots embedded within the cavities is used to explore mode energies and quality factors, Q, as a function of cavity design parameters. Optimised Q values are in excess of 7,500 for the modified y-dipole mode. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Theory of trapped polaritons in patterned microcavitiesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2006Pierre Lugan Abstract We consider the system of a quantum well embedded in a planar semiconductor microcavity with a shallow circular mesa patterned on top of the cavity spacer. For this system we develop the linear coupling theory of polaritons. We then compute polariton eigenstates and the corresponding optical spectrum. The theory predicts the existence of laterally confined polariton states with a discrete energy spectrum, as well as continuum states above the finite mesa potential barrier. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Influence of the phonon-exciton interaction on exciton-exciton quantum correlation in semiconductor microcavitiesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2006S. Portolan Abstract We present an extension of the previous descriptions based on the Dynamics Controlled Truncation Scheme of light-matter interaction beyond mean-field, including the microscopic description of the exciton-photon interaction. This enables the microscopic analysis of the influence of decoherence and noise on the polariton quantum correlations originating from nonlinear optical processes. We expand the operators involved in the dynamics in terms of exact eigenstates of the electron system, the photon and phonon operators and treat phonon-assisted transitions within the Markov approximation. In particular, we present quantum Heisenberg-Langevin equations describing light-induced excitations in semiconductor systems interacting with the phonon bath. This theoretical framework is applied to study the influence of dephasing and noise due to photoluminescence on polariton quantum correlations generated by parametric emission in microcavities. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Optical characterization of GaN microcavity fabricated by wet etchingPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2006C.-Y. Lu Abstract We report a novel technique to fabricate gallium nitride (GaN) microcavities by combining the methods of photo-enhanced wet chemical oxidation and crystallographic etching. Such GaN microcavities exhibit mirror-like vertical facets composing of {1100}GaN and various gemoetry of hexagonal, trigonal and cylindrical shapes. The emission spectra of the GaN micro-cavities are found in resonance with the whispering gallery (WG) modes when pumped with a 266 nm Nd:YAG laser. The signatures of GaN microcavities were further characterized by an increase of the WG mode spacing with the reduced device size and suppression of the side mode emission intensity with pump intensity. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Angular switching of the linear polarization of the emission in InGaAs microcavitiesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2005A. Amo Abstract The angular dependence of the degree of linear polarization of the emission is presented for an InGaAs microcavity at several detunings. For emission angles (, ) close to the growth direction, polarizations as high as +80% for lower branch polaritons at negative detuning are found. This polarization degree abruptly switches to negative values (up to ,90%) for emission angles outside a narrow cone of about ±2º. A similar behaviour, with smaller values of the polarization, is found at 0 and positive detunings. The relation between these effects and cavity birefringence is discussed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Spontaneous emission from semiconductor nanocrystals in coupled spherical microcavitiesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2005Yu. P. Rakovich Abstract We report on the coherent coupling of whispering gallery modes (WGM) in a photonic molecule formed from two melamine-formaldehyde spherical microcavities coated with a thin shell of light-emitting CdTe nanocrystals (NCs). Utilizing different excitation conditions the splitting of the WGM resonances originating from bonding and anti-bonding branches of the photonic states is observed and fine structure consisting of very sharp peaks resulting from lifting of the WGM degeneracy has been detected. Time-resolved measurements showed a slight increase in the spontaneous emission rate of NCs in a photonic molecule when compared to the spontaneous emission rate for NCs coating a single microsphere. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] E-beam pumped resonant periodic gain GaInP/AlGaInP VCSELPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2005V. Yu. Abstract 25-period Ga0.5In0.5P/(Al0.7Ga0.3)0.5In0.5P quantum well structure was grown by MOVPE on GaAs substrates misoriented by 100 from (001) to (111)A and fabricated into a microcavities with dielectric oxide mirrors. The structure period and mirror design were chosen to provide resonant periodic gain. A non-uniformity of 5% in the total structure thickness across the 2 inch wafer was used for studying laser characteristics depending on mismatching structure period from resonance condition. The laser wavelength, threshold and output power was found to depend critically on the alignment of QW period with both the cavity and the MQW gain spectrum. Lasing in the 625,650 nm spectral range with output power up to 9 W (0.45 MW/cm2) was achieved under scanning electron beam longitudinal pumping at room temperature. The minimum threshold current density for a 40 keV electron energy was 8 A/cm2 (0.32 MW/cm2). In order to control the lasing threshold to within 10 % of its minimum, the MQW period should be tuned to the optimum value with an accuracy of about 1 %. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Proceedings of the 3rd International Conference on Physics of Light,Matter Coupling in Nanostructures (PLMCN3)PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2004Alexey Kavokin The 3rd International Conference on Physics of Light,Matter Coupling in Nanostructures (PLMCN3) took place in Acireale, Sicily, Italy from 1,4 October 2003. The aim of this conference was to review the fundamental background for realization of a new generation of opto-electronic devices such as polariton lasers, new optical switches and emitters based on microcavities. The idea was to combine the experience of spectroscopists and theorists with that of specialists in crystals growth of wide-band semiconductors (GaN, CdTe, ZnSe, ZnO) and organic materials. [source] Preface: phys. stat. sol. (c) 1/6PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2004Alexey Kavokin This volume contains some of the papers presented at the Third International Conference on Physics of Light,Matter Coupling in Nanostructures (PLMCN3) which took place in Acireale, Sicily, from 1 to 4 October 2003. This meeting was fourth in the series started by PLMCN (St. Nectaire, 2000) and continued by PLMCN1 (Rome, 2001) and PLMCN2 (Rithymnon, 2002). All four conferences had the same format (about 70 participants), similar subject scope (interface between fundamental physics of light,matter coupling phenomena and applied research on new semiconductor materials and low-dimensional structures), and the proceedings of all of them have been published in physica status solidi. During these four years, a huge progress has been achieved in the understanding of exciton,polariton effects in microcavities. From the discovery of stimulated scattering of polaritons in 1999 to the first experimental reports of polariton Bose condensation and lasing, attention to this rapidly developing research area has been increased drastically. It is clear now that realization of a new generation of opto-electronic devices, referred to as polariton devices, is a realistic task for the coming decade. To achieve this target, much work has to be done both in fundamental research on dynamics of exciton,polaritons in microcavities and experimental realization of high-quality microcavities presumably based on wide-band gap semiconductors like GaN, ZnO, ZnSe, suitable for the observation of strong exciton,light coupling at room temperature. Forty nine research teams from twelve European countries have created a Polariton Consortium aimed at integration of the European research effort towards fabrication of polariton devices. PLMCN3 was not only an international conference devoted, in particular, to the research on polariton devices, but also the first scientific meeting of this community. The PLMCN meetings since the very first one have been sponsored by the US Army European Research Office (ERO). This time, with the initiative of Jim Harvey from ERO, a special session has been organized on the devices of 21st century, where a number of intriguing ideas have been proposed on new light sources, polariton lasers, and quantum memory elements based on microcavities. A special prize for the most crazy but realizable idea has been won by Misha Portnoi (Exeter) for the concept of a white diode based on a microcavity. Each PLMCN meeting brings participants from new countries. This time, the traditionally strong participation from Japan, Russia, the European Union and the USA has been enforced by a representative delegation from Israel and two speakers from Mexico. We are looking forward for new-comers from other countries not yet involved in the PLMCN community, to join us for the next meeting to be held in St. Petersburg on 29 June,3 July 2004. Sergey Ivanov from the A. F. Ioffe Institute chairs the local Organizing Committee of this future conference. We are going to keep a unique informal and creative atmosphere being characteristic of the PLMCN meetings. We invite all those who wish to know more about light,matter coupling in solids or to present any new interesting results in this area and at the same time to enjoy the beautiful city of St. Petersburg, to contact Sergey Ivanov (ivan@beam.ioffe.rssi.ru) or myself (kavokin@lasmea.univ-bpclermont.fr). We are looking forward to welcoming you in St. Petersburg! [source] Statistics of polaritons in microcavitiesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2004Paolo Schwendimann Abstract We discuss the quantum statistical properties of exciton-polaritons in semiconductor microcavities. The nonlinear dynamics is treated within a model of interacting bosons for the signal, pump and idler modes. We focus on the regime of parametric amplification below threshold. We present the time evolution of the signal and idler modes towards their stationary solutions and evaluate the amount of squeezing of the radiation emitted out of the microcavity in a configuration, which is relevant for experiments. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Hot embossing of discrete micropartsPOLYMER ENGINEERING & SCIENCE, Issue 10 2009Ramasubramani Kuduva-Raman-Thanumoorthy The hot embossing process has so far been developed mainly for replication of surface structures on thermoplastic substrates. Because of the lack of a through-thickness action, fabrication of discrete microparts such as microgears is considered difficult. In this study, embossing molds having multiple microcavities were used in a through-thickness embossing process with a rubber-assisted ejection mechanism. Microparts made of HDPE and ABS with each part weighing approximately 1 and 1.4 mg, respectively, were produced. When in the mold, embossed microparts were intermittently connected to each other through thin residual films of a thickness approximately 20 ,m. The residual films were detached from the microparts during a rubber-assisted ejection stage. Because no resin delivery paths, e.g., runners and gates, are needed for microcavities on the multicavity embossing mold, this micropart fabrication process could replace micro injection molding in many applications. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source] Adhesion of thermoplastic elastomer on surface treated aluminum by injection moldingPOLYMER ENGINEERING & SCIENCE, Issue 8 2007P.A. Fabrin Hybrid composites were prepared using insert injection molding without preheating. Thermoplastic elastomer (TPE) was overmolded on etched aluminum sheets having porous surface to provide large contact area between insert and TPE. The resulting bond strength was studied using a 180° peel test. The effect of aluminum microstructure and various processing steps of the surface treatment procedures on adhesion were studied. Maximum peel strength obtained was 9.33 N/cm using P2 treatment with alkaline-acid pretreatment. Lowest peel strength of 1.68 N/cm was achieved by alkaline,acid treatment. Increasing insert thickness lowers the peel strength since large heat capacity of thicker insert cools the melt and limits penetration of the melt to insert microcavities. At certain insert thickness microcavities are impregnated by the melt and no additional effect can be obtained by decreasing the insert thickness. POLYM. ENG. SCI., 47:1187,1191, 2007. © 2007 Society of Plastics Engineers [source] Study on squeezing flow during nonisothermal embossing of polymer microstructuresPOLYMER ENGINEERING & SCIENCE, Issue 5 2005Donggang Yao A numerical simulation of the hot embossing process with nonisothermal embossing conditions was carried out to observe the flow pattern of poly (methyl methacrylate) into microcavities. The microcavity was isomorphically downsized. The ratio of the cavity width over the cavity thickness was maintained constant at 8:1 throughout the analysis, while the cavity thickness varied from 200 ,m to 0.5 ,m. It was found that as the microcavity was downsized, the filling mechanism varied. For larger cavity thicknesses (e.g., 100 ,m), the polymer flow climbed along the wall of the heated die and was then compressed downward and squeezed outward. In contrast, for a smaller cavity thickness (e.g., 5 ,m), the flow was uniform and the wall-climbing flow was absent. This size effect was correlated with the uniformity (UNF) of the temperature distribution of the polymer substrate during the embossing process. For larger cavity thicknesses, the high temperature zone was localized in the vicinity of the die wall, and consequently localized wall-climbing flow occurred. The size effect in nonisothermal embossing was also studied experimentally, and localized flow was observed for larger cavities but not for smaller cavities. POLYM. ENG. SCI., 45:652,660, 2005. © 2005 Society of Plastics Engineers [source] | ||||||||||||||||