The Detection of Helicobacter hepaticus Using Whispering-Gallery Mode Microcavity Optical Sensors

Directory of Open Access Journals (Sweden)

Mark E. Anderson

2015-08-01

Full Text Available Current bacterial detection techniques are relatively slow, require bulky instrumentation, and usually require some form of specialized training. The gold standard for bacterial detection is culture testing, which can take several days to receive a viable result. Therefore, simpler detection techniques that are both fast and sensitive could greatly improve bacterial detection and identification. Here, we present a new method for the detection of the bacteria Helicobacter hepaticus using whispering-gallery mode (WGM optical microcavity-based sensors. Due to minimal reflection losses and low material adsorption, WGM-based sensors have ultra-high quality factors, resulting in high-sensitivity sensor devices. In this study, we have shown that bacteria can be non-specifically detected using WGM optical microcavity-based sensors. The minimum detection for the device was 1 × 104 cells/mL, and the minimum time of detection was found to be 750 s. Given that a cell density as low as 1 × 103 cells/mL for Helicobacter hepaticus can cause infection, the limit of detection shown here would be useful for most levels where Helicobacter hepaticus is biologically relevant. This study suggests a new approach for H. hepaticus detection using label-free optical sensors that is faster than, and potentially as sensitive as, standard techniques.

Biexcitons or bipolaritons in a semiconductor microcavity

DEFF Research Database (Denmark)

Borri, Paola; Langbein, Wolfgang Werner; Woggon, U

2000-01-01

A well-resolved nonlinear optical transition associated with biexcitons is observed in a high-quality microcavity with a Rabi splitting exceeding the binding energy of biexcitons in the embedded quantum well. This transition is identified as an induced absorption from the lower polariton to the b......A well-resolved nonlinear optical transition associated with biexcitons is observed in a high-quality microcavity with a Rabi splitting exceeding the binding energy of biexcitons in the embedded quantum well. This transition is identified as an induced absorption from the lower polariton...

Optical characterization of porous silicon microcavities for glucose oxidase biosensing

Science.gov (United States)

Palestino, G.; Agarwal, V.; Garcia, D. B.; Legros, R.; Pérez, E.; Gergely, C.

2008-04-01

PSi microcavity (PSiMc) is characterized by a narrow resonance peak in the optical spectrum that is very sensitive to small changes in the refractive index. We report that the resonant optical cavities of PSi structures can be used to enhance the detection of labeled fluorescent biomolecules. Various PSi configurations were tested in order to compare the optical response of the PSi devices to the capture of organic molecules. Morphological and topographical analyses were performed on PSiMc using Atomic Force (AFM) and Scanning Electron (SEM) microscopies. The heterogeneity in pores lengths resulting from etching process assures a better penetration of larger molecules into the pores and sensor sensitivity depends on the pore size. Molecular detection is monitored by the successive red shifts in the reflectance spectra after the stabilization of PSiMc with 3-aminopropyltriethoxysilane (APTES). The glucose oxidase was cross linked into the PSiMc structures following a silane-glutaraldehyde (GTA) chemistry.

Strong Exciton-photon Coupling in Semiconductor Microcavities

DEFF Research Database (Denmark)

Jensen, Jacob Riis; Borri, Paola; Hvam, Jørn Märcher

1999-01-01

The basic building block of vertical cavity surface emitting lasers (VCSELs) and high efficiency diodes, is a quantum well embedded in a semiconductor microcavity. The high finesse that may be achieved in such a cavity is utilised to get a low threshold current in the VCSELs and a high directiona......The basic building block of vertical cavity surface emitting lasers (VCSELs) and high efficiency diodes, is a quantum well embedded in a semiconductor microcavity. The high finesse that may be achieved in such a cavity is utilised to get a low threshold current in the VCSELs and a high......-optical switches based on semiconductor microcavities....

Rabi-like splitting from large area plasmonic microcavity

Directory of Open Access Journals (Sweden)

Fatemeh Hosseini Alast

2017-08-01

Full Text Available Rabi-like splitting was observed from a hybrid plasmonic microcavity. The splitting comes from the coupling of cavity mode with the surface plasmon polariton mode; anti-crossing was observed alongside the modal conversional channel on the reflection light measurement. The hybrid device consists of a 10x10 mm2 ruled metal grating integrated onto the Fabry-Perot microcavity. The 10x10 mm2 ruled metal grating fabricated from laser interference and the area is sufficiently large to be used in the practical optical device. The larger area hybrid plasmonic microcavity can be employed in polariton lasers and biosensors.

Detection and light enhancement of glucose oxidase adsorbed on porous silicon microcavities

Energy Technology Data Exchange (ETDEWEB)

Palestino, Gabriela [GES-UMR 5650, CNRS-Universite Montpellier II, Montpellier (France); Facultad de Ciencias Quimicas, Universidad Autonoma de San Luis Potosi, San Luis Potosi (Mexico); Martin, Marta; Legros, Rene; Cloitre, Thierry; Gergely, Csilla [GES-UMR 5650, CNRS-Universite Montpellier II, Montpellier (France); Agarwal, Vivechana [CIICAP, Universidad Autonoma del Estado de Morelos, Cuernavaca (Mexico); Zimanyi, Laszlo [EA4203, Faculte d' Odontologie, Universite Montpellier I, Montpellier (France); Institute of Biophysics, Biological Research Center, Hungarian Academy of Sciences, Szeged (Hungary)

2009-07-15

Porous silicon (PSi) structure is used as support material to detect protein infiltration and to induce fluorescence and second harmonic light enhancement from glucose oxidase (GOX). Functionalization and protein infiltration is monitored by specular reflectometry. Optical response enhancement of PSi microcavity structures compared to PSi single layers or Bragg mirrors is observed, when GOX is impregnated. Penetration of organic molecules along the PSi microcavity structure is demonstrated by energy dispersive X-ray profile. Enhanced fluorescence emission of GOX when adsorbed on PSi microcavity is evidenced by multi-photon microscopy (MPM). Second harmonic light generation is observed at some particular pores of PSi and subsequent resonance enhancement of the signal arising from the GOX adsorbed within the pores is detected. Our work evidences an improved device functionality of GOX-PSi microcavities due to strongly confined and localized light emission within these structures. This opens the way towards the application of PSi microcavity structures as amended biosensors based on their locally enhanced optical response. The second main achievement lies in the novelty of the used techniques. In contrast to the specular reflectometry used to monitor the macroscopic optical response of PSi structures, MPM presents a valuable alternative microscopic technique probing individual pores. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

High-fidelity quantum gates on quantum-dot-confined electron spins in low-Q optical microcavities

Science.gov (United States)

Li, Tao; Gao, Jian-Cun; Deng, Fu-Guo; Long, Gui-Lu

2018-04-01

We propose some high-fidelity quantum circuits for quantum computing on electron spins of quantum dots (QD) embedded in low-Q optical microcavities, including the two-qubit controlled-NOT gate and the multiple-target-qubit controlled-NOT gate. The fidelities of both quantum gates can, in principle, be robust to imperfections involved in a practical input-output process of a single photon by converting the infidelity into a heralded error. Furthermore, the influence of two different decay channels is detailed. By decreasing the quality factor of the present microcavity, we can largely increase the efficiencies of these quantum gates while their high fidelities remain unaffected. This proposal also has another advantage regarding its experimental feasibility, in that both quantum gates can work faithfully even when the QD-cavity systems are non-identical, which is of particular importance in current semiconductor QD technology.

A porous silicon optical microcavity for sensitive bacteria detection

International Nuclear Information System (INIS)

Li Sha; Huang Jianfeng; Cai Lintao

2011-01-01

A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak (∼10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml -1 at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml -1 . The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

A porous silicon optical microcavity for sensitive bacteria detection

Science.gov (United States)

Li, Sha; Huang, Jianfeng; Cai, Lintao

2011-10-01

A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak (~10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml - 1 at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml - 1. The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

A porous silicon optical microcavity for sensitive bacteria detection

Energy Technology Data Exchange (ETDEWEB)

Li Sha; Huang Jianfeng; Cai Lintao, E-mail: lt.cai@siat.ac.cn [CAS Key Lab of Health Informatics, Shenzhen Key Laboratory of Cancer Nanotechnology, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055 (China)

2011-10-21

A porous silicon microcavity (PSM) is highly sensitive to subtle interface changes due to its high surface area, capillary condensation ability and a narrow resonance peak ({approx}10 nm). Based on the well-defined optical properties of a PSM, we successfully fabricated a bacteria detection chip for molecular or subcellular analysis by surface modification using undecylenic acid (UA), and the specific recognition binding of vancomycin to the D-alanyl-D-alanine of bacteria. The red shift of the PSM resonance peak showed a good linear relationship with bacteria concentration ranging from 100 to 1000 bacteria ml{sup -1} at the level of relative standard deviation of 0.994 and detection limit of 20 bacteria ml{sup -1}. The resulting PSM sensors demonstrated high sensitivity, good reproducibility, fast response and low cost for biosensing.

Tapered optical fiber tip probes based on focused ion beam-milled Fabry-Perot microcavities

Science.gov (United States)

André, Ricardo M.; Warren-Smith, Stephen C.; Becker, Martin; Dellith, Jan; Rothhardt, Manfred; Zibaii, M. I.; Latifi, H.; Marques, Manuel B.; Bartelt, Hartmut; Frazão, Orlando

2016-09-01

Focused ion beam technology is combined with dynamic chemical etching to create microcavities in tapered optical fiber tips, resulting in fiber probes for temperature and refractive index sensing. Dynamic chemical etching uses hydrofluoric acid and a syringe pump to etch standard optical fibers into cone structures called tapered fiber tips where the length, shape, and cone angle can be precisely controlled. On these tips, focused ion beam is used to mill several different types of Fabry-Perot microcavities. Two main cavity types are initially compared and then combined to form a third, complex cavity structure. In the first case, a gap is milled on the tapered fiber tip which allows the external medium to penetrate the light guiding region and thus presents sensitivity to external refractive index changes. In the second, two slots that function as mirrors are milled on the tip creating a silica cavity that is only sensitive to temperature changes. Finally, both cavities are combined on a single tapered fiber tip, resulting in a multi-cavity structure capable of discriminating between temperature and refractive index variations. This dual characterization is performed with the aid of a fast Fourier transform method to separate the contributions of each cavity and thus of temperature and refractive index. Ultimately, a tapered optical fiber tip probe with sub-standard dimensions containing a multi-cavity structure is projected, fabricated, characterized and applied as a sensing element for simultaneous temperature and refractive index discrimination.

Black phosphorus-based one-dimensional photonic crystals and microcavities.

Science.gov (United States)

Kriegel, Ilka; Toffanin, Stefano; Scotognella, Francesco

2016-11-10

The latest achievements in the fabrication of thin layers of black phosphorus (BP), toward the technological breakthrough of a phosphorene atomically thin layer, are paving the way for their use in electronics, optics, and optoelectronics. In this work, we have simulated the optical properties of one-dimensional photonic structures, i.e., photonic crystals and microcavities, in which few-layer BP is one of the components. The insertion of the 5-nm black phosphorous layers leads to a photonic band gap in the photonic crystals and a cavity mode in the microcavity that is interesting for light manipulation and emission enhancement.

Progress Toward Single-Photon-Level Nonlinear Optics in Crystalline Microcavities

Science.gov (United States)

Kowligy, Abijith S.

Over the last two decades, the emergence of quantum information science has uncovered many practical applications in areas such as communications, imaging, and sensing where harnessing quantum features of Nature provides tremendous benefits over existing methods exploiting classical physical phenomena. In this effort, one of the frontiers of research has been to identify and utilize quantum phenomena that are not susceptible to environmental and parasitic noise processes. Quantum photonics has been at the forefront of these studies because it allows room-temperature access to its inherently quantum-mechanical features, and allows leveraging the mature telecommunication industry. Accompanying the weak environmental influence, however, are also weak optical nonlinearities. Efficient nonlinear optical interactions are indispensible for many of the existing protocols for quantum optical computation and communication, e.g. high-fidelity entangling quantum logic gates rely on large nonlinear responses at the one- or few-photon-level. While this has been addressed to a great extent by interfacing photons with single quantum emitters and cold atomic gases, scalability has remained elusive. In this work, we identify the macroscopic second-order nonlinear polarization as a robust platform to address this challenge, and utilize the recent advances in the burgeoning field of optical microcavities to enhance this nonlinear response. In particular, we show theoretically that by using the quantum Zeno effect, low-noise, single-photon-level optical nonlinearities can be realized in lithium niobate whispering-gallery-mode microcavities, and present experimental progress toward this goal. Using the measured strength of the second-order nonlinear response in lithium niobate, we modeled the nonlinear system in the strong coupling regime using the Schrodinger picture framework and theoretically demonstrated that the single-photon-level operation can be observed for cavity lifetimes in

Raman scattering enhancement in photon-plasmon resonance mediated metal-dielectric microcavity

International Nuclear Information System (INIS)

Guddala, Sriram; Narayana Rao, D.; Dwivedi, Vindesh K.; Vijaya Prakash, G.

2013-01-01

Here, we report the photon-plasmon interaction scheme and enhanced field strengths resulted into the amplification of phonon in a novel microcavity. A metal-dielectric microcavity, with unified cavity photonic mode and localized surface plasmon resonances, is visualized by impregnating the gold nanoparticles into the deep see-through nano-sized pores of porous silicon microcavity. The intense optical field strengths resulting from the photon-plasmon interactions are probed by both resonant and non-resonant Raman scattering experiments. Due to photon-plasmon-phonon interaction mechanism, several orders of enhancement in the intensity of scattered Raman Stokes photon (at 500 cm −1 ) are observed. Our metal nanoparticle-microcavity hybrid system shows the potential to improve the sensing figure of merit as well as the applications of plasmonics for optoelectronics, photovoltaics, and related technologies

Liquid sensing capability of rolled-up tubular optical microcavities: a theoretical study.

Science.gov (United States)

Zhao, Fangyuan; Zhan, Tianrong; Huang, Gaoshan; Mei, Yongfeng; Hu, Xinhua

2012-10-07

Rolled-up tubular optical microcavities are a novel type of optical sensor for identifying different liquids and monitoring single cells. Based on a Mie scattering method, we systematically study the optical resonances and liquid sensing capability of microtubes. Analytical formulas are presented to calculate the resonant wavelengths λ(r), Q factors, sensitivities S and figures of merit QS. Both ideal and rolled-up microtubes are considered for different optical materials in tube walls (refractive indices ranging from 1.5 to 2.5) and for three setups: tube-in-liquid, hollow-tube-in-liquid and liquid-in-tube. It is found that for rolled-up microtubes, the highest QS can be achieved by using the liquid-in-tube setup and very thin wall thicknesses. A maximal sensitivity is found in the case of the liquid cylinder. Our theory well explains a recent experiment under the setup of tube-in-liquid. It is also found that, although it describes the case of tube-in-liquid well, the waveguide approximation approach is not suitable for the case of liquid-in-tube. The results could be useful to design better optofluidic devices based on rolled-up microtubes.

Anomalous normal mode oscillations in semiconductor microcavities

Energy Technology Data Exchange (ETDEWEB)

Wang, H. [Univ. of Oregon, Eugene, OR (United States). Dept. of Physics; Hou, H.Q.; Hammons, B.E. [Sandia National Labs., Albuquerque, NM (United States)

1997-04-01

Semiconductor microcavities as a composite exciton-cavity system can be characterized by two normal modes. Under an impulsive excitation by a short laser pulse, optical polarizations associated with the two normal modes have a {pi} phase difference. The total induced optical polarization is then expected to exhibit a sin{sup 2}({Omega}t)-like oscillation where 2{Omega} is the normal mode splitting, reflecting a coherent energy exchange between the exciton and cavity. In this paper the authors present experimental studies of normal mode oscillations using three-pulse transient four wave mixing (FWM). The result reveals surprisingly that when the cavity is tuned far below the exciton resonance, normal mode oscillation in the polarization is cos{sup 2}({Omega}t)-like, in contrast to what is expected form the simple normal mode model. This anomalous normal mode oscillation reflects the important role of virtual excitation of electronic states in semiconductor microcavities.

Optical responses in single-crystalline organic microcavities

International Nuclear Information System (INIS)

Kondo, H.; Yamamoto, Y.; Takeda, A.; Yamamoto, S.; Kurisu, H.

2008-01-01

The anisotropic response of cavity polaritons is investigated in an organic microcavity composed of a single-crystalline anthracene film sandwiched between two distributed Bragg reflectors. Upper and lower cavity polariton modes are observed as sharp spectral peaks in the transmission spectra. Dispersion relation for cavity polaritons is obtained as a function of thickness of the thin film. Using this relation, the vacuum Rabi splitting energy for this system is estimated to be 340 meV

Optical responses in single-crystalline organic microcavities

Energy Technology Data Exchange (ETDEWEB)

Kondo, H. [Department of Physics, Ehime University, Matsuyama, 2-5 Bunkyo-cho, Matsuyama 790-8577 (Japan)], E-mail: kondo@phys.sci.ehime-u.ac.jp; Yamamoto, Y.; Takeda, A. [Department of Physics, Ehime University, Matsuyama, 2-5 Bunkyo-cho, Matsuyama 790-8577 (Japan); Yamamoto, S.; Kurisu, H. [Department of Advanced Materials Science and Engineering, Yamaguchi University, Ube, Yamaguchi 755-8611 (Japan)

2008-05-15

The anisotropic response of cavity polaritons is investigated in an organic microcavity composed of a single-crystalline anthracene film sandwiched between two distributed Bragg reflectors. Upper and lower cavity polariton modes are observed as sharp spectral peaks in the transmission spectra. Dispersion relation for cavity polaritons is obtained as a function of thickness of the thin film. Using this relation, the vacuum Rabi splitting energy for this system is estimated to be 340 meV.

Entanglement purification and concentration of electron-spin entangled states using quantum-dot spins in optical microcavities

International Nuclear Information System (INIS)

Wang Chuan; Zhang Yong; Jin Guangsheng

2011-01-01

We present an entanglement purification protocol and an entanglement concentration protocol for electron-spin entangled states, resorting to quantum-dot spin and optical-microcavity-coupled systems. The parity-check gates (PCGs) constructed by the cavity-spin-coupling system provide a different method for the entanglement purification of electron-spin entangled states. This protocol can efficiently purify an electron ensemble in a mixed entangled state. The PCGs can also concentrate electron-spin pairs in less-entangled pure states efficiently. The proposed methods are more flexible as only single-photon detection and single-electron detection are needed.

Wavelength tuning of porous silicon microcavities

International Nuclear Information System (INIS)

Mulders, J.; Reece, P.; Zheng, W.H.; Lerondel, G.; Sun, B.; Gal, M.

2002-01-01

Full text: In the last decade much attention has been given to porous silicon (PS) for optoelectronic applications, which include efficient room temperature light emission as well as microcavity formation. Due to the large specific surface area, the use of porous silicon microcavities (PSMs) has been proposed for chemical sensing. Large wavelength shifts have indicated that the optical properties of PSMs are indeed strongly dependent on the environment. In this paper, we report the shifting of the resonance frequency of high quality PSMs, with the aim of tuning a future PS device to a certain required wavelength. The PSM samples were prepared by anodically etching p + -doped (5mΩcm) bulk silicon wafer in a solution (25%) of aqueous HF and ethanol. The device structure consisted of a PS layer sandwiched between 2 stacks of thin PS layers with alternating high and low effective refractive indices (RI), i.e. distributed Bragg mirrors (DBM). The layer thickness depends on the etch time while the porosity and hence refractive index is determined by the current density as the Si is etched. The position and the width of the stop-band can be fully controlled by the design of the DBMs, with the microcavity resonance mode sitting within the stop-band. We achieved tuning of the microcavity resonance by a number of methods, including temperature dependent tuning. The temperature induced wavelength shift was found to be of the order of 10 -15 nm. Computer modeling of these changes in the reflectivity spectra allowed us to quantify the changes of the effective refractive index and the respective layer thicknesses

Strong exciton-photon coupling in organic single crystal microcavity with high molecular orientation

Energy Technology Data Exchange (ETDEWEB)

Goto, Kaname [Department of Electronics, Graduate School of Science and Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan); Yamashita, Kenichi, E-mail: yamasita@kit.ac.jp [Faculty of Electrical Engineering and Electronics, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan); Yanagi, Hisao [Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Yamao, Takeshi; Hotta, Shu [Faculty of Materials Science and Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan)

2016-08-08

Strong exciton-photon coupling has been observed in a highly oriented organic single crystal microcavity. This microcavity consists of a thiophene/phenylene co-oligomer (TPCO) single crystal laminated on a high-reflection distributed Bragg reflector. In the TPCO crystal, molecular transition dipole was strongly polarized along a certain horizontal directions with respect to the main crystal plane. This dipole polarization causes significantly large anisotropies in the exciton transition and optical constants. Especially the anisotropic exciton transition was found to provide the strong enhancement in the coupling with the cavity mode, which was demonstrated by a Rabi splitting energy as large as ∼100 meV even in the “half-vertical cavity surface emitting lasing” microcavity structure.

Strong exciton-photon coupling in organic single crystal microcavity with high molecular orientation

Science.gov (United States)

Goto, Kaname; Yamashita, Kenichi; Yanagi, Hisao; Yamao, Takeshi; Hotta, Shu

2016-08-01

Strong exciton-photon coupling has been observed in a highly oriented organic single crystal microcavity. This microcavity consists of a thiophene/phenylene co-oligomer (TPCO) single crystal laminated on a high-reflection distributed Bragg reflector. In the TPCO crystal, molecular transition dipole was strongly polarized along a certain horizontal directions with respect to the main crystal plane. This dipole polarization causes significantly large anisotropies in the exciton transition and optical constants. Especially the anisotropic exciton transition was found to provide the strong enhancement in the coupling with the cavity mode, which was demonstrated by a Rabi splitting energy as large as ˜100 meV even in the "half-vertical cavity surface emitting lasing" microcavity structure.

Strong exciton-photon coupling in organic single crystal microcavity with high molecular orientation

International Nuclear Information System (INIS)

Goto, Kaname; Yamashita, Kenichi; Yanagi, Hisao; Yamao, Takeshi; Hotta, Shu

2016-01-01

Strong exciton-photon coupling has been observed in a highly oriented organic single crystal microcavity. This microcavity consists of a thiophene/phenylene co-oligomer (TPCO) single crystal laminated on a high-reflection distributed Bragg reflector. In the TPCO crystal, molecular transition dipole was strongly polarized along a certain horizontal directions with respect to the main crystal plane. This dipole polarization causes significantly large anisotropies in the exciton transition and optical constants. Especially the anisotropic exciton transition was found to provide the strong enhancement in the coupling with the cavity mode, which was demonstrated by a Rabi splitting energy as large as ∼100 meV even in the “half-vertical cavity surface emitting lasing” microcavity structure.

Development of L-lactate dehydrogenase biosensor based on porous silicon resonant microcavities as fluorescence enhancers.

Science.gov (United States)

Jenie, S N Aisyiyah; Prieto-Simon, Beatriz; Voelcker, Nicolas H

2015-12-15

The up-regulation of L-lactate dehydrogenase (LDH), an intracellular enzyme present in most of all body tissues, is indicative of several pathological conditions and cellular death. Herein, we demonstrate LDH detection using porous silicon (pSi) microcavities as a luminescence-enhancing optical biosensing platform. Non-fluorescent resazurin was covalently attached onto the pSi surface via thermal hydrocarbonisation, thermal hydrosylilation and acylation. Each surface modification step was confirmed by means of FTIR and the optical shifts of the resonance wavelength of the microcavity. Thermal hydrocarbonisation also afforded excellent surface stability, ensuring that the resazurin was not reduced on the pSi surface. Using a pSi microcavity biosensor, the fluorescence signal upon detection of LDH was amplified by 10 and 5-fold compared to that of a single layer and a detuned microcavity, respectively, giving a limit of detection of 0.08 U/ml. The biosensor showed a linear response between 0.16 and 6.5 U/ml, covering the concentration range of LDH in normal as well as damaged tissues. The biosensor was selective for LDH and did not produce a signal upon incubation with another NAD-dependant enzyme L-glutamic dehydrogenase. The use of the pSi microcavity as a sensing platform reduced reagent usage by 30% and analysis time threefold compared to the standard LDH assay in solution. Copyright © 2015 Elsevier B.V. All rights reserved.

The role of group index engineering in series-connected photonic crystal microcavities for high density sensor microarrays

International Nuclear Information System (INIS)

Zou, Yi; Zhu, Liang; Chen, Ray T.; Chakravarty, Swapnajit

2014-01-01

We experimentally demonstrate an efficient and robust method for series connection of photonic crystal microcavities that are coupled to photonic crystal waveguides in the slow light transmission regime. We demonstrate that group index taper engineering provides excellent optical impedance matching between the input and output strip waveguides and the photonic crystal waveguide, a nearly flat transmission over the entire guided mode spectrum and clear multi-resonance peaks corresponding to individual microcavities that are connected in series. Series connected photonic crystal microcavities are further multiplexed in parallel using cascaded multimode interference power splitters to generate a high density silicon nanophotonic microarray comprising 64 photonic crystal microcavity sensors, all of which are interrogated simultaneously at the same instant of time

The role of group index engineering in series-connected photonic crystal microcavities for high density sensor microarrays

Energy Technology Data Exchange (ETDEWEB)

Zou, Yi, E-mail: yzou@utexas.edu; Zhu, Liang; Chen, Ray T., E-mail: raychen@uts.cc.utexas.edu [Department of Electrical and Computer Engineering, Microelectronics Research Center, University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States); Chakravarty, Swapnajit, E-mail: swapnajit.chakravarty@omegaoptics.com [Omega Optics, Inc., 8500 Shoal Creek Blvd., Austin, Texas 78757 (United States)

2014-04-07

We experimentally demonstrate an efficient and robust method for series connection of photonic crystal microcavities that are coupled to photonic crystal waveguides in the slow light transmission regime. We demonstrate that group index taper engineering provides excellent optical impedance matching between the input and output strip waveguides and the photonic crystal waveguide, a nearly flat transmission over the entire guided mode spectrum and clear multi-resonance peaks corresponding to individual microcavities that are connected in series. Series connected photonic crystal microcavities are further multiplexed in parallel using cascaded multimode interference power splitters to generate a high density silicon nanophotonic microarray comprising 64 photonic crystal microcavity sensors, all of which are interrogated simultaneously at the same instant of time.

On-Chip High-Finesse Fabry-Perot Microcavities for Optical Sensing and Quantum Information

Directory of Open Access Journals (Sweden)

Mohammad H. Bitarafan

2017-07-01

Full Text Available For applications in sensing and cavity-based quantum computing and metrology, open-access Fabry-Perot cavities—with an air or vacuum gap between a pair of high reflectance mirrors—offer important advantages compared to other types of microcavities. For example, they are inherently tunable using MEMS-based actuation strategies, and they enable atomic emitters or target analytes to be located at high field regions of the optical mode. Integration of curved-mirror Fabry-Perot cavities on chips containing electronic, optoelectronic, and optomechanical elements is a topic of emerging importance. Micro-fabrication techniques can be used to create mirrors with small radius-of-curvature, which is a prerequisite for cavities to support stable, small-volume modes. We review recent progress towards chip-based implementation of such cavities, and highlight their potential to address applications in sensing and cavity quantum electrodynamics.

On-Chip High-Finesse Fabry-Perot Microcavities for Optical Sensing and Quantum Information.

Science.gov (United States)

Bitarafan, Mohammad H; DeCorby, Ray G

2017-07-31

For applications in sensing and cavity-based quantum computing and metrology, open-access Fabry-Perot cavities-with an air or vacuum gap between a pair of high reflectance mirrors-offer important advantages compared to other types of microcavities. For example, they are inherently tunable using MEMS-based actuation strategies, and they enable atomic emitters or target analytes to be located at high field regions of the optical mode. Integration of curved-mirror Fabry-Perot cavities on chips containing electronic, optoelectronic, and optomechanical elements is a topic of emerging importance. Micro-fabrication techniques can be used to create mirrors with small radius-of-curvature, which is a prerequisite for cavities to support stable, small-volume modes. We review recent progress towards chip-based implementation of such cavities, and highlight their potential to address applications in sensing and cavity quantum electrodynamics.

All silicon waveguide spherical microcavity coupler device.

Science.gov (United States)

Xifré-Pérez, E; Domenech, J D; Fenollosa, R; Muñoz, P; Capmany, J; Meseguer, F

2011-02-14

A coupler based on silicon spherical microcavities coupled to silicon waveguides for telecom wavelengths is presented. The light scattered by the microcavity is detected and analyzed as a function of the wavelength. The transmittance signal through the waveguide is strongly attenuated (up to 25 dB) at wavelengths corresponding to the Mie resonances of the microcavity. The coupling between the microcavity and the waveguide is experimentally demonstrated and theoretically modeled with the help of FDTD calculations.

Novel emission phenomena in organic microcavities (Conference Presentation)

Science.gov (United States)

Leo, Karl

2016-09-01

Organic light emitting diodes (OLED) are today a mature techology and have reached high efficiency both in monochrome and white devices. One of the main research areas for further improvement is still the optical design which enables many new approaches to enhance efficiency and realize special emission properties. In this talk, I will review our recent work on OLED outcoupling, in particular for devices encapsulated in microcavities and patterned structures.

Multimode laser emission from free-standing cylindrical microcavities

Energy Technology Data Exchange (ETDEWEB)

Peter, Jaison, E-mail: jaisonpeter@cusat.ac.in; Radhakrishnan, P.; Nampoori, V.P.N.; Kailasnath, M.

2014-05-01

We report a well resolved whispering gallery mode (WGM) laser emission from a free-standing microring cavity based on a dye doped hollow polymer optical fiber (DDHPOF), which is transversely pumped by a pulsed Nd:YAG laser. The microring laser is characterized by a well-defined, low threshold pump power at which the emission spectral intensity dramatically increases and collapses into several dominant microcavity laser modes with reduced mode spacing and high Q-value. Resonant modes are excited inside the gain medium which is strongly confined along the radial direction so that the spacing of lasing modes is controlled by the diameter of the cylindrical microcavity. A variation in the free spectral range of WGM spectra from 0.23 to 0.09 nm coupled with a red-shift is observed with an increase in the diameter of DDHPOFs. - Highlights: • Different diameter free-standing cylindrical microcavity lasers have been fabricated and their performances have been evaluated. • The microring laser is characterized by a well-defined, low threshold pump power, with reduced mode spacing and high Q-value. • When the diameter of DDHPOF increases, the number of lasing peaks increases along with the decrease of the FSR as observed from our studies. • It is also found that whispering gallery lasing envelope is shifted from 559 to 571 nm (Stokes shift) with the diameter.

Scalable quantum computing based on stationary spin qubits in coupled quantum dots inside double-sided optical microcavities.

Science.gov (United States)

Wei, Hai-Rui; Deng, Fu-Guo

2014-12-18

Quantum logic gates are the key elements in quantum computing. Here we investigate the possibility of achieving a scalable and compact quantum computing based on stationary electron-spin qubits, by using the giant optical circular birefringence induced by quantum-dot spins in double-sided optical microcavities as a result of cavity quantum electrodynamics. We design the compact quantum circuits for implementing universal and deterministic quantum gates for electron-spin systems, including the two-qubit CNOT gate and the three-qubit Toffoli gate. They are compact and economic, and they do not require additional electron-spin qubits. Moreover, our devices have good scalability and are attractive as they both are based on solid-state quantum systems and the qubits are stationary. They are feasible with the current experimental technology, and both high fidelity and high efficiency can be achieved when the ratio of the side leakage to the cavity decay is low.

A SIMULTANEOUS MULTI-PROBE DETECTION LABEL-FREE OPTICAL-RESOLUTION PHOTOACOUSTIC MICROSCOPY TECHNIQUE BASED ON MICROCAVITY TRANSDUCER

Directory of Open Access Journals (Sweden)

YONGBO WU

2013-07-01

Full Text Available We demonstrate the feasibility of simultaneous multi-probe detection for an optical-resolution photoacoustic microscopy (OR-PAM system. OR-PAM has elicited the attention of biomedical imaging researchers because of its optical absorption contrast and high spatial resolution with great imaging depth. OR-PAM allows label-free and noninvasive imaging by maximizing the optical absorption of endogenous biomolecules. However, given the inadequate absorption of some biomolecules, detection sensitivity at the same incident intensity requires improvement. In this study, a modulated continuous wave with power density less than 3 mW/cm2 (1/4 of the ANSI safety limit excited the weak photoacoustic (PA signals of biological cells. A microcavity transducer is developed based on the bulk modulus of gas five orders of magnitude lower than that of solid; air pressure variation is inversely proportional to cavity volume at the same temperature increase. Considering that a PA wave expands in various directions, detecting PA signals from different positions and adding them together can increase detection sensitivity and signal-to-noise ratio. Therefore, we employ four detectors to acquire tiny PA signals simultaneously. Experimental results show that the developed OR-PAM system allows the label-free imaging of cells with weak optical absorption.

Effect of interface disorder on quantum well excitons and microcavity polaritons

International Nuclear Information System (INIS)

Savona, Vincenzo

2007-01-01

The theory of the linear optical response of excitons in quantum wells and polaritons in planar semiconductor microcavities is reviewed, in the light of the existing experiments. For quantum well excitons, it is shown that disorder mainly affects the exciton centre-of-mass motion and is modelled by an effective Schroedinger equation in two dimensions. For polaritons, a unified model accounting for quantum well roughness and fluctuations of the microcavity thickness is developed. Numerical results confirm that polaritons are mostly affected by disorder acting on the photon component, thus confirming existing studies on the influence of exciton disorder. The polariton localization length is estimated to be in the few-micrometres range, depending on the amplitude of disorder, in agreement with recent experimental findings

The combination of high Q factor and chirality in twin cavities and microcavity chain

Science.gov (United States)

Song, Qinghai; Zhang, Nan; Zhai, Huilin; Liu, Shuai; Gu, Zhiyuan; Wang, Kaiyang; Sun, Shang; Chen, Zhiwei; Li, Meng; Xiao, Shumin

2014-01-01

Chirality in microcavities has recently shown its bright future in optical sensing and microsized coherent light sources. The key parameters for such applications are the high quality (Q) factor and large chirality. However, the previous reported chiral resonances are either low Q modes or require very special cavity designs. Here we demonstrate a novel, robust, and general mechanism to obtain the chirality in circular cavity. By placing a circular cavity and a spiral cavity in proximity, we show that ultra-high Q factor, large chirality, and unidirectional output can be obtained simultaneously. The highest Q factors of the non-orthogonal mode pairs are almost the same as the ones in circular cavity. And the co-propagating directions of the non-orthogonal mode pairs can be reversed by tuning the mode coupling. This new mechanism for the combination of high Q factor and large chirality is found to be very robust to cavity size, refractive index, and the shape deformation, showing very nice fabrication tolerance. And it can be further extended to microcavity chain and microcavity plane. We believe that our research will shed light on the practical applications of chirality and microcavities. PMID:25262881

Deterministic photonic spatial-polarization hyper-controlled-not gate assisted by a quantum dot inside a one-side optical microcavity

International Nuclear Information System (INIS)

Ren, Bao-Cang; Wei, Hai-Rui; Deng, Fu-Guo

2013-01-01

To date, all work concerning the construction of quantum logic gates, an essential part of quantum computing, has focused on operating in one degree of freedom (DOF) for quantum systems. Here, we investigate the possibility of achieving scalable photonic quantum computing based on two DOFs for quantum systems. We construct a deterministic hyper-controlled-not (hyper-CNOT) gate operating in both the spatial mode and polarization DOFs for a photon pair simultaneously, using the giant optical Faraday rotation induced by a single-electron spin in a quantum dot inside a one-side optical microcavity as a result of cavity quantum electrodynamics. With this hyper-CNOT gate and linear optical elements, two-photon four-qubit cluster entangled states can be prepared and analyzed, which give an application to manipulate more information with less resources. We analyze the experimental feasibility of this hyper-CNOT gate and show that it can be implemented with current technology. (letter)

Strong coupling and polariton lasing in Te based microcavities embedding (Cd,Zn)Te quantum wells

Energy Technology Data Exchange (ETDEWEB)

Rousset, J.-G., E-mail: j-g.rousset@fuw.edu.pl; Piętka, B.; Król, M.; Mirek, R.; Lekenta, K.; Szczytko, J.; Borysiuk, J.; Suffczyński, J.; Kazimierczuk, T.; Goryca, M.; Smoleński, T.; Kossacki, P.; Nawrocki, M.; Pacuski, W. [Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, PL-02-093 Warszawa (Poland)

2015-11-16

We report on properties of an optical microcavity based on (Cd,Zn,Mg)Te layers and embedding (Cd,Zn)Te quantum wells. The key point of the structure design is the lattice matching of the whole structure to MgTe, which eliminates the internal strain and allows one to embed an arbitrary number of unstrained quantum wells in the microcavity. We evidence the strong light-matter coupling regime already for the structure containing a single quantum well. Embedding four unstrained quantum wells results in further enhancement of the exciton-photon coupling and the polariton lasing in the strong coupling regime.

Weak Localization of Light in a Disordered Microcavity

Science.gov (United States)

Gurioli, M.; Bogani, F.; Cavigli, L.; Gibbs, H.; Khitrova, G.; Wiersma, D. S.

2005-05-01

We report the observation of weak localization of light in a semiconductor microcavity. The intrinsic disorder in a microcavity leads to multiple scattering and hence to static speckle. We show that averaging over realizations of the disorder reveals a coherent backscattering cone that has a coherent enhancement factor ≥2, as required by reciprocity. The coherent backscattering cone is observed along a ring-shaped pattern due to confinement by the microcavity.

Dye Giant Absorption and Light Confinement Effects in Porous Bragg Microcavities

DEFF Research Database (Denmark)

Oliva-Ramírez, Manuel; Gil-Rostra, Jorge; Simonsen, Adam C.

2018-01-01

This work presents a simple experimental procedure to probe light confinement effects in photonic structures. Two types of porous 1D Bragg microcavities with two resonant peaks in the reflection gap were prepared by physical vapor deposition at oblique angle configurations and then infiltrated...... with dye solutions of increasing concentrations. The unusual position shift and intensity drop of the transmitted resonant peak observed when it was scanned through the dye absorption band have been accounted for by the effect of the light trapped at their optical defect layer. An experimentally observed...... giant absorption of the dye molecules and a strong anomalous dispersion in the refractive index of the solution are claimed as the reasons for the observed variations in the Bragg microcavity resonant feature. Determining the giant absorption of infiltrated dye solutions is proposed as a general...

Polariton condensation phase diagram in wide-band-gap planar microcavities: GaN versus ZnO

Science.gov (United States)

Jamadi, O.; Réveret, F.; Mallet, E.; Disseix, P.; Médard, F.; Mihailovic, M.; Solnyshkov, D.; Malpuech, G.; Leymarie, J.; Lafosse, X.; Bouchoule, S.; Li, F.; Leroux, M.; Semond, F.; Zuniga-Perez, J.

2016-03-01

The polariton condensation phase diagram is compared in GaN and ZnO microcavities grown on mesa-patterned silicon substrate. Owing to a common platform, these microcavities share similar photonic properties with large quality factors and low photonic disorder, which makes it possible to determine the optimal spot diameter and to realize a thorough phase diagram study. Both systems have been investigated under the same experimental conditions. The experimental results and the subsequent analysis reveal clearly that longitudinal optical phonons have no influence in the thermodynamic region of the condensation phase diagram, while they allow a strong (slight) decrease of the polariton lasing threshold in the trade-off zone (kinetic region). Phase diagrams are compared with numerical simulations using Boltzmann equations, and are in satisfactory agreement. A lower polariton lasing threshold has been measured at low temperature in the ZnO microcavity, as is expected due to a larger Rabi splitting. This study highlights polariton relaxation mechanisms and their importance in polariton lasing.

Controllable optical bistability in photonic-crystal one-atom laser

International Nuclear Information System (INIS)

Guo Xiaoyong; Lue Shuchen

2009-01-01

We investigate the property of optical bistability in a photonic-crystal one-atom laser when nonlinear microcavity is present. The physical system consists of a coherently driven two-level light emitter strongly coupled to a high-quality microcavity which is embedded within a photonic crystal and another coherent probing field which has incident into the microcavity. In our case, the microcavity is fabricated by nonlinear material and placed as an impurity in photonic crystal. This study reveals that such a system can exhibit optical bistability. The dependence of threshold value and hysteresis loop on the photonic band gap of the photonic crystal, driving field Rabi frequency and dephasing processes, are studied. Our results clearly illustrate the ability to control optical bistability through suitable photonic-crystal architectures and external coherent driving field, and this study suggests that in a photonic-crystal nonlinear microcavity, the one-atom laser acts as an effective controllable bistable device in the design of all-light digital computing systems in the near future.

Enhanced photoresponse of monolayer molybdenum disulfide (MoS2) based on microcavity structure

Science.gov (United States)

Lu, Yanan; Yang, Guofeng; Wang, Fuxue; Lu, Naiyan

2018-05-01

There is an increasing interest in using monolayer molybdenum disulfide (MoS2) for optoelectronic devices because of its inherent direct band gap characteristics. However, the weak absorption of monolayer MoS2 restricts its applications, novel concepts need to be developed to address the weakness. In this work, monolayer MoS2 monolithically integrates with plane microcavity structure, which is formed by the top and bottom chirped distributed Bragg reflector (DBR), is demonstrated to improve the absorption of MoS2. The optical absorption is 17-fold enhanced, reaching values over 70% at work wavelength. Moreover, the monolayer MoS2-based photodetector device with microcavity presents a significantly increased photoresponse, demonstrating its promising prospects in MoS2-based optoelectronic devices.

Dynamics in terahertz semiconductor microcavity: quantum noise spectra

Science.gov (United States)

Jabri, H.; Eleuch, H.

2018-05-01

We investigate the physics of an optical semiconductor microcavity containing a coupled double quantum well interacting with cavity photons. The photon statistics of the transmitted light by the cavity is explored. We show that the nonlinear interactions in the direct and indirect excitonic modes generate an important squeezing despite the weak nonlinearities. When the strong coupling regime is achieved, the noise spectra of the system is dominated by the indirect exciton distribution. At the opposite, in the weak regime, direct excitons contribute much larger in the noise spectra.

A microring multimode laser using hollow polymer optical fibre

Indian Academy of Sciences (India)

Dye-doped optical fibre; fibre laser; microcavity; whispering gallery mode. ... Cylindrical microcavities with diameters 155, 340 and 615 m were fabricated from a dye-doped hollow polymer optical fibre preform. ... International School of Photonics, Cochin University of Science and Technology, Kochi 682 022, India ...

Room temperature current injection polariton light emitting diode with a hybrid microcavity.

Science.gov (United States)

Lu, Tien-Chang; Chen, Jun-Rong; Lin, Shiang-Chi; Huang, Si-Wei; Wang, Shing-Chung; Yamamoto, Yoshihisa

2011-07-13

The strong light-matter interaction within a semiconductor high-Q microcavity has been used to produce half-matter/half-light quasiparticles, exciton-polaritons. The exciton-polaritons have very small effective mass and controllable energy-momentum dispersion relation. These unique properties of polaritons provide the possibility to investigate the fundamental physics including solid-state cavity quantum electrodynamics, and dynamical Bose-Einstein condensates (BECs). Thus far the polariton BEC has been demonstrated using optical excitation. However, from a practical viewpoint, the current injection polariton devices operating at room temperature would be most desirable. Here we report the first realization of a current injection microcavity GaN exciton-polariton light emitting diode (LED) operating under room temperature. The exciton-polariton emission from the LED at photon energy 3.02 eV under strong coupling condition is confirmed through temperature-dependent and angle-resolved electroluminescence spectra.

Bistability and self-oscillations effects in a polariton-laser semiconductor microcavity

International Nuclear Information System (INIS)

Cotta, E A; Matinaga, F M

2007-01-01

We report an experimental observation of polaritonic optical bistability of the laser emission in a planar semiconductor microcavity with a 100 0 A GaAs single quantum well in the strong-coupling regime. The bistability curves show crossings that indicate a competition between a Kerr-like effect induced by the polariton population and thermal effects. Associated with the bistability, laser-like emission occurs at the bare cavity mode

Coupling of a single NV center to a fiber-based microcavity

International Nuclear Information System (INIS)

Christoph Becher

2014-01-01

The read-out of the spin state of a NV center in diamond or the transfer of quantum information between its spin and a photon would profit enormously from coupling the NV center's optical transitions to a microcavity with a highly directional output. We here report on such a coupling of a single NV center in a nanodiamond to a fiber-based, tunable microcavity at room temperature. Making use of the NV center's strongly broadened emission we operate in the regime of phonon-assisted cavity seeding and realize a widely tunable, narrow-band single photon source. A master equation model well reproduces our experimental results and predicts a transition into a Purcell-enhanced emission regime at low temperatures where up to 65% of the NV emission would be channeled into the cavity mode for our given experimental parameters. Further reducing scattering losses from the nanodiamonds could enable schemes for cavity-enhanced spin measurements or creation of entangled states. (author)

A new microcavity design for single molecule detection

International Nuclear Information System (INIS)

Steiner, M.; Schleifenbaum, F.; Stupperich, C.; Failla, A.V.; Hartschuh, A.; Meixner, A.J.

2006-01-01

We present a new microcavity design which allows for efficient detection of single molecules by measuring the molecular fluorescence emission coupled into a resonant cavity mode. The Fabry-Perot-type microresonator consists of two silver mirrors separated by a thin polymer film doped with dye molecules in ultralow concenctration. By slightly tilting one of the mirrors different cavity lengths can be selected within the same sample. Locally, on a μm scale, the microcavity still acts as a planar Fabry-Perot resonator. Using scanning confocal fluorescence microscopy, single emitters on resonance with a single mode of the microresonator can be spatially addressed. Our microcavity is demonstrated to be well-suited for investigating the coupling mechanism between single quantum emitters and single modes of the electromagnetic field. The microcavity layout could be integrated in a lab-on-a-microchip design for ultrasensitive microfluidic analytics and can be considered as an important improvement for single photon sources based on single molecules operating at room temperature

Scheme for implementing N-qubit controlled phase gate of photons assisted by quantum-dot-microcavity coupled system: optimal probability of success

International Nuclear Information System (INIS)

Cui, Wen-Xue; Hu, Shi; Wang, Hong-Fu; Zhu, Ai-Dong; Zhang, Shou

2015-01-01

The direct implementation of multiqubit controlled phase gate of photons is appealing and important for reducing the complexity of the physical realization of linear-optics-based practical quantum computer and quantum algorithms. In this letter we propose a nondestructive scheme for implementing an N-qubit controlled phase gate of photons with a high success probability. The gate can be directly implemented with the self-designed quantum encoder circuits, which are probabilistic optical quantum entangler devices and can be achieved using linear optical elements, single-photon superposition state, and quantum dot coupled to optical microcavity. The calculated results indicate that both the success probabilities of the quantum encoder circuit and the N-qubit controlled phase gate in our scheme are higher than those in the previous schemes. We also consider the effects of the side leakage and cavity loss on the success probability and the fidelity of the quantum encoder circuit for a realistic quantum-dot-microcavity coupled system. (letter)

Realization and optical characterisation of micro-cavities in strong coupling regime using self-assembled multi-quantum wells structure of 2D perovskites

International Nuclear Information System (INIS)

Lanty, Gaetan

2011-01-01

The research work which is reported in this manuscript focuses on 2D perovskites and their use to obtain micro-cavities working in the strong coupling regime. Perovskite structure forms a multi-quantum wells in which the excitonic states have a high oscillator strength and a large binding energy (a few 100 MeV) due to quantum and dielectric confinement effects. A first axis of this work was to collect information on the excitonic properties of these materials. On a particular perovskite (PEPI), we performed photoluminescence and pump-probe measurements, which seem to suggest the existence, under high excitation density, a process of Auger recombination of excitons. A second research axis was to put in cavity thin layers of some perovskites. With PEPI and PEPC perovskites, we have shown that the realization of micro-cavities with a quality factor of the order of ten is sufficient to obtain at room temperature, the strong coupling regime in absorption and emission with Rabi splitting up to 220 MeV. A bottleneck effect has been clearly demonstrated for the PEPI microcavity. We have also shown that perovskites could be associated with inorganic semiconductors in 'hybrid' micro-cavities. According Agranovich et al., these micro-cavities could present polariton lasing with lower quality factors. To this end, the ZnO/MFMPB association seems particularly promising. (author)

Handbook of optical microcavities

CERN Document Server

Choi, Anthony H W

2014-01-01

An optical cavity confines light within its structure and constitutes an integral part of a laser device. Unlike traditional gas lasers, semiconductor lasers are invariably much smaller in dimensions, making optical confinement more critical than ever. In this book, modern methods that control and manipulate light at the micrometer and nanometer scales by using a variety of cavity geometries and demonstrate optical resonance from ultra-violet (UV) to infra-red (IR) bands across multiple material platforms are explored. The book has a comprehensive collection of chapters that cover a wide range

Broad-spectrum enhanced absorption of graphene-molybdenum disulfide photovoltaic cells in metal-mirror microcavity

Science.gov (United States)

Jiang-Tao, Liu; Yun-Kai, Cao; Hong, Tong; Dai-Qiang, Wang; Zhen-Hua, Wu

2018-04-01

The optical absorption of graphene-molybdenum disulfide photovoltaic cells (GM-PVc) in wedge-shaped metal-mirror microcavities (w-MMCs) combined with a spectrum-splitting structure was studied. Results showed that the combination of spectrum-splitting structure and w-MMC can enable the light absorption of GM-PVcs to reach about 65% in the broad spectrum. The influence of processing errors on the absorption of GM-PVcs in w-MMCs was 3-14 times lower than that of GM-PVcs in wedge photonic crystal microcavities. The light absorption of GM-PVcs reached 60% in the broad spectrum, even with the processing errors. The proposed structure is easy to implement and may have potentially important applications in the development of ultra-thin and high-efficiency solar cells and optoelectronic devices.

Recycling microcavity optical biosensors.

Science.gov (United States)

Hunt, Heather K; Armani, Andrea M

2011-04-01

Optical biosensors have tremendous potential for commercial applications in medical diagnostics, environmental monitoring, and food safety evaluation. In these applications, sensor reuse is desirable to reduce costs. To achieve this, harsh, wet chemistry treatments are required to remove surface chemistry from the sensor, typically resulting in reduced sensor performance and increased noise due to recognition moiety and optical transducer degradation. In the present work, we suggest an alternative, dry-chemistry method, based on O2 plasma treatment. This approach is compatible with typical fabrication of substrate-based optical transducers. This treatment completely removes the recognition moiety, allowing the transducer surface to be refreshed with new recognition elements and thus enabling the sensor to be recycled.

Exciton-polariton dynamics in a GaAs bulk microcavity

Science.gov (United States)

Ceccherini, S.; Gurioli, M.; Bogani, F.; Colocci, M.; Tredicucci, A.; Bassani, F.; Beltram, F.; Sorba, L.

1998-01-01

We present a full analysis of exciton dynamics in a GaAs λ/2 bulk microcavity following excitation by ultrafast laser pulses. Coherent dynamics was probed by means of an interferometric technique; beating and dephasing times were studied for various excitation intensities. At high incident power, population effects begin to show up reducing exciton oscillator strength and suppressing Rabi splitting. This feature produces marked non-linearities in the input-output characteristic of the optical functions, which were studied in view of reaching bistable operation. Theoretical calculations performed within the transfer-matrix framework show good agreement with experimental results.

Digital optical computer II

Science.gov (United States)

Guilfoyle, Peter S.; Stone, Richard V.

1991-12-01

OptiComp is currently completing a 32-bit, fully programmable digital optical computer (DOC II) that is designed to operate in a UNIX environment running RISC microcode. OptiComp's DOC II architecture is focused toward parallel microcode implementation where data is input in a dual rail format. By exploiting the physical principals inherent to optics (speed and low power consumption), an architectural balance of optical interconnects and software code efficiency can be achieved including high fan-in and fan-out. OptiComp's DOC II program is jointly sponsored by the Office of Naval Research (ONR), the Strategic Defense Initiative Office (SDIO), NASA space station group and Rome Laboratory (USAF). This paper not only describes the motivational basis behind DOC II but also provides an optical overview and architectural summary of the device that allows the emulation of any digital instruction set.

High Sensitivity Detection of CdSe/ZnS Quantum Dot-Labeled DNA Based on N-type Porous Silicon Microcavities.

Science.gov (United States)

Lv, Changwu; Jia, Zhenhong; Lv, Jie; Zhang, Hongyan; Li, Yanyu

2017-01-01

N-type macroporous silicon microcavity structures were prepared using electrochemical etching in an HF solution in the absence of light and oxidants. The CdSe/ZnS water-soluble quantum dot-labeled DNA target molecules were detected by monitoring the microcavity reflectance spectrum, which was characterized by the reflectance spectrum defect state position shift resulting from changes to the structures' refractive index. Quantum dots with a high refractive index and DNA coupling can improve the detection sensitivity by amplifying the optical response signals of the target DNA. The experimental results show that DNA combined with a quantum dot can improve the sensitivity of DNA detection by more than five times.

A versatile tunable microcavity for investigation of light-matter interaction

Science.gov (United States)

Mochalov, Konstantin E.; Vaskan, Ivan S.; Dovzhenko, Dmitriy S.; Rakovich, Yury P.; Nabiev, Igor

2018-05-01

Light-matter interaction between a molecular ensemble and a confined electromagnetic field is a promising area of research, as it allows light-control of the properties of coupled matter. The common way to achieve coupling is to place an ensemble of molecules or quantum emitters into a cavity. In this approach, light-matter coupling is evidenced by modification of the spectral response of the emitter, which depends on the strength of interaction between emitter and cavity modes. However, there is not yet a user-friendly approach that allows the study of a large number of different and replaceable samples in a wide optical range using the same resonator. Here, we present the design of such a device that can speed up and facilitate investigation of light-matter interaction ranging from weak to strong coupling regimes in ultraviolet-visible and infrared (IR) spectral regions. The device is based on a tunable unstable λ/2 Fabry-Pérot microcavity consisting of plane and convex mirrors that satisfy the plane-parallelism condition at least at one point of the curved mirror and minimize the mode volume. Fine tuning of the microcavity length is provided by a Z-piezopositioner in a range up to 10 μm with a step of several nm. This design makes a device a versatile instrument that ensures easy finding of optimal conditions for light-matter interaction for almost any sample in both visible and IR areas, enabling observation of both electronic and vibrational couplings with microcavity modes thus paving the way to investigation of various coupling effects including Raman scattering enhancement, modification of chemical reactivity rate, lasing, and long-distance nonradiative energy transfer.

A parametric study on the PD pulses activity within micro-cavities

Science.gov (United States)

Ganjovi, Alireza A.

2016-03-01

A two-dimensional kinetic model has been used to parametric investigation of the spark-type partial discharge pulses inside the micro-cavities. The model is based on particle-in-cell methods with Monte Carlo Collision techniques for modeling of collisions. Secondary processes like photo-emission and cathode-emission are considered. The micro-cavity may be sandwiched between two metallic conductors or two dielectrics. The discharge within the micro-cavity is studied in conjunction with the external circuit. The model is used to successfully simulate the evolution of the discharge and yield useful information about the build-up of space charge within the micro-cavity and the consequent modification of the applied electric field. The phase-space scatter plots for electrons, positive, and negative ions are obtained in order to understand the manner in which discharge progresses over time. The rise-time and the magnitude of the discharge current pulse are obtained and are seen to be affected by micro-cavity dimensions, gas pressure within the micro-cavity, and the permittivity of surrounding dielectrics. The results have been compared with existing experimental, theoretical, and computational results, wherever possible. An attempt has been made to understand the nature of the variations in terms of the physical processes involved.

Real-Time and In-Flow Sensing Using a High Sensitivity Porous Silicon Microcavity-Based Sensor.

Science.gov (United States)

Caroselli, Raffaele; Martín Sánchez, David; Ponce Alcántara, Salvador; Prats Quilez, Francisco; Torrijos Morán, Luis; García-Rupérez, Jaime

2017-12-05

Porous silicon seems to be an appropriate material platform for the development of high-sensitivity and low-cost optical sensors, as their porous nature increases the interaction with the target substances, and their fabrication process is very simple and inexpensive. In this paper, we present the experimental development of a porous silicon microcavity sensor and its use for real-time in-flow sensing application. A high-sensitivity configuration was designed and then fabricated, by electrochemically etching a silicon wafer. Refractive index sensing experiments were realized by flowing several dilutions with decreasing refractive indices, and measuring the spectral shift in real-time. The porous silicon microcavity sensor showed a very linear response over a wide refractive index range, with a sensitivity around 1000 nm/refractive index unit (RIU), which allowed us to directly detect refractive index variations in the 10 -7 RIU range.

Acoustic trapping in bubble-bounded micro-cavities

Science.gov (United States)

O'Mahoney, P.; McDougall, C.; Glynne-Jones, P.; MacDonald, M. P.

2016-12-01

We present a method for controllably producing longitudinal acoustic trapping sites inside microfluidic channels. Air bubbles are injected into a micro-capillary to create bubble-bounded `micro-cavities'. A cavity mode is formed that shows controlled longitudinal acoustic trapping between the two air/water interfaces along with the levitation to the centre of the channel that one would expect from a lower order lateral mode. 7 μm and 10 μm microspheres are trapped at the discrete acoustic trapping sites in these micro-cavities.We show this for several lengths of micro-cavity.

Fabrication of silicon molds for polymer optics

DEFF Research Database (Denmark)

Nilsson, Daniel; Jensen, Søren; Menon, Aric Kumaran

2003-01-01

A silicon mold used for structuring polymer microcavities for optical applications is fabricated, using a combination of DRIE (deep reactive ion etching) and anisotropic chemical wet etching with KOH + IPA. For polymer optical microcavities, low surface roughness and vertical sidewalls are often ...... and KOH + IPA etch have been optimized. To reduce stiction between the silicon mold and the polymers used for molding, the mold is coated with a teflon-like material using the DRIE system. Released polymer microstructures characterized with AFM and SEM are also presented....

Polariton-acoustic-phonon interaction in a semiconductor microcavity

Science.gov (United States)

Cassabois, G.; Triques, A. L. C.; Bogani, F.; Delalande, C.; Roussignol, Ph.; Piermarocchi, C.

2000-01-01

The broadening of polariton lines by acoustic phonons is investigated in a semiconductor microcavity by means of interferometric correlation measurements with subpicosecond resolution. A decrease of the polariton-acoustic phonon coupling is clearly observed for the lower polariton branch as one approaches the resonance between exciton and photon states. This behavior cannot be explained in terms of a semiclassical linear dispersion theory but requires a full quantum description of the microcavity in the strong-coupling regime.

Real-Time and In-Flow Sensing Using a High Sensitivity Porous Silicon Microcavity-Based Sensor

Directory of Open Access Journals (Sweden)

Raffaele Caroselli

2017-12-01

Full Text Available Porous silicon seems to be an appropriate material platform for the development of high-sensitivity and low-cost optical sensors, as their porous nature increases the interaction with the target substances, and their fabrication process is very simple and inexpensive. In this paper, we present the experimental development of a porous silicon microcavity sensor and its use for real-time in-flow sensing application. A high-sensitivity configuration was designed and then fabricated, by electrochemically etching a silicon wafer. Refractive index sensing experiments were realized by flowing several dilutions with decreasing refractive indices, and measuring the spectral shift in real-time. The porous silicon microcavity sensor showed a very linear response over a wide refractive index range, with a sensitivity around 1000 nm/refractive index unit (RIU, which allowed us to directly detect refractive index variations in the 10−7 RIU range.

Full color organic light-emitting devices with microcavity structure and color filter.

Science.gov (United States)

Zhang, Weiwei; Liu, Hongyu; Sun, Runguang

2009-05-11

This letter demonstrated the fabrication of the full color passive matrix organic light-emitting devices based on the combination of the microcavity structure, color filter and a common white polymeric OLED. In the microcavity structure, patterned ITO terraces with different thickness were used as the anode as well as cavity spacer. The primary color emitting peaks were originally generated by the microcavity and then the second resonance peak was absorbed by the color filter.

Biexcitons in semiconductor microcavities

DEFF Research Database (Denmark)

Borri, P.; Langbein, W.; Woggon, U.

2003-01-01

in the microcavity, even if the vacuum Rabi splitting exceeds the biexciton binding energy. However, the presence of a longitudinal built-in electric field that results in a Stark effect slightly reducing the binding energy compared to the value measured on a reference bare quantum well is experimentally pointed out...

Advances of Optofluidic Microcavities for Microlasers and Biosensors

Directory of Open Access Journals (Sweden)

Zhiqing Feng

2018-03-01

Full Text Available Optofluidic microcavities with high Q factor have made rapid progress in recent years by using various micro-structures. On one hand, they are applied to microfluidic lasers with low excitation thresholds. On the other hand, they inspire the innovation of new biosensing devices with excellent performance. In this article, the recent advances in the microlaser research and the biochemical sensing field will be reviewed. The former will be categorized based on the structures of optical resonant cavities such as the Fabry–Pérot cavity and whispering gallery mode, and the latter will be classified based on the working principles into active sensors and passive sensors. Moreover, the difficulty of single-chip integration and recent endeavors will be briefly discussed.

Optical microcavities and enhanced electroluminescence from electroformed Al-Al{sub 2}O{sub 3}-Ag diodes

Energy Technology Data Exchange (ETDEWEB)

Hickmott, T. W. [Department of Physics, State University of New York at Albany, Albany, New York 12222 (United States)

2013-12-21

Electroluminescence (EL) and electron emission into vacuum (EM) occur when a non-destructive dielectric breakdown of Al-Al{sub 2}O{sub 3}-Ag diodes, electroforming, results in the development of a filamentary region in which current-voltage (I-V) characteristics exhibit voltage-controlled negative resistance. The temperature dependence of I-V curves, EM, and, particularly, EL of Al-Al{sub 2}O{sub 3}-Ag diodes with anodic Al{sub 2}O{sub 3} thicknesses between 12 nm and 30 nm, has been studied. Two filters, a long-pass (LP) filter with transmission of photons with energies less than 3.0 eV and a short-pass (SP) filter with photon transmission between 3.0 and 4.0 eV, have been used to characterize EL. The voltage threshold for EL with the LP filter, V{sub LP}, is ∼1.5 V. V{sub LP} is nearly independent of Al{sub 2}O{sub 3} thickness and of temperature and is 0.3–0.6 V less than the threshold voltage for EL for the SP filter, V{sub SP}. EL intensity is primarily between 1.8 and 3.0 eV when the bias voltage, V{sub S} ≲ 7 V. EL in the thinnest diodes is enhanced compared to EL in thicker diodes. For increasing V{sub S}, for diodes with the smallest Al{sub 2}O{sub 3} thicknesses, there is a maximum EL intensity, L{sub MX}, at a voltage, V{sub LMX}, followed by a decrease to a plateau. L{sub MX} and EL intensity at 4.0 V in the plateau region depend exponentially on Al{sub 2}O{sub 3} thickness. The ratio of L{sub MX} at 295 K for a diode with 12 nm of Al{sub 2}O{sub 3} to L{sub MX} for a diode with 25 nm of Al{sub 2}O{sub 3} is ∼140. The ratio of EL intensity with the LP filter to EL intensity with the SP filter, LP/SP, varies between ∼3 and ∼35; it depends on Al{sub 2}O{sub 3} thickness and V{sub S}. Enhanced EL is attributed to the increase of the spontaneous emission rate of a dipole in a non-resonant optical microcavity. EL photons interact with the Ag and Al films to create surface plasmon polaritons (SPPs) at the metal-Al{sub 2}O

Transition between bulk and surface refractive index sensitivity of micro-cavity in-line Mach-Zehnder interferometer induced by thin film deposition.

Science.gov (United States)

Śmietana, Mateusz; Janik, Monika; Koba, Marcin; Bock, Wojtek J

2017-10-16

In this work we discuss the refractive index (RI) sensitivity of a micro-cavity in-line Mach-Zehnder interferometer in the form of a cylindrical hole (40-50 μm in diameter) fabricated in a standard single-mode optical fiber using a femtosecond laser. The surface of the micro-cavity was coated with up to 400 nm aluminum oxide thin film using the atomic layer deposition method. Next, the film was progressively chemically etched and the influence on changes in the RI of liquid in the micro-cavity was determined at different stages of the experiment, i.e., at different thicknesses of the film. An effect of transition between sensitivity to the film thickness (surface) and the RI of liquid in the cavity (bulk) is demonstrated for the first time. We have found that depending on the interferometer working conditions determined by thin film properties, the device can be used for investigation of phenomena taking place at the surface, such as in case of specific label-free biosensing applications, or for small-volume RI analysis as required in analytical chemistry.

Modal analysis of spontaneous emission in a planar microcavity

International Nuclear Information System (INIS)

Rigneault, H.; Monneret, S.

1996-01-01

A complete set of cavity modes in planar dielectric microcavities is presented which naturally includes guided modes. We show that most of these orthonormal fields can be derived from a coherent superposition of plane waves incoming on the stack from the air and from the substrate. Spontaneous emission of a dipole located inside the microcavity is analyzed, in terms of cavity modes. Derivation of the radiation pattern in the air and in the substrate is presented. The power emitted into the guided modes is also determined. Finally, a numerical analysis of the radiative properties of an erbium atom located in a Fabry-Pacute erot multilayer dielectric microcavity is investigated. We show that a large amount of light is emitted into the guided modes of the structure, in spite of the Fabry-Pacute erot resonance, which increases the spontaneous emission rate in a normal direction. copyright 1996 The American Physical Society

Microcavity single virus detection and sizing with molecular sensitivity

Science.gov (United States)

Dantham, V. R.; Holler, S.; Kolchenko, V.; Wan, Z.; Arnold, S.

2013-02-01

We report the label-free detection and sizing of the smallest individual RNA virus, MS2 by a spherical microcavity. Mass of this virus is ~6 ag and produces a theoretical resonance shift ~0.25 fm upon adsorbing an individual virus at the equator of the bare microcavity, which is well below the r.m.s background noise of 2 fm. However, detection was accomplished with ease (S/N = 8, Q = 4x105) using a single dipole stimulated plasmonic-nanoshell as a microcavity wavelength shift enhancer. Analytical expressions based on the "reactive sensing principle" are developed to extract the radius of the virus from the measured signals. Estimated limit of detection for these experiments was ~0.4 ag or 240 kDa below the size of all known viruses, largest globular and elongated proteins [Phosphofructokinase (345 kDa) and Fibrinogen (390 kDa), respectively].

Computational Modeling of Photonic Crystal Microcavity Single-Photon Emitters

Science.gov (United States)

Saulnier, Nicole A.

Conventional cryptography is based on algorithms that are mathematically complex and difficult to solve, such as factoring large numbers. The advent of a quantum computer would render these schemes useless. As scientists work to develop a quantum computer, cryptographers are developing new schemes for unconditionally secure cryptography. Quantum key distribution has emerged as one of the potential replacements of classical cryptography. It relics on the fact that measurement of a quantum bit changes the state of the bit and undetected eavesdropping is impossible. Single polarized photons can be used as the quantum bits, such that a quantum system would in some ways mirror the classical communication scheme. The quantum key distribution system would include components that create, transmit and detect single polarized photons. The focus of this work is on the development of an efficient single-photon source. This source is comprised of a single quantum dot inside of a photonic crystal microcavity. To better understand the physics behind the device, a computational model is developed. The model uses Finite-Difference Time-Domain methods to analyze the electromagnetic field distribution in photonic crystal microcavities. It uses an 8-band k · p perturbation theory to compute the energy band structure of the epitaxially grown quantum dots. We discuss a method that combines the results of these two calculations for determining the spontaneous emission lifetime of a quantum dot in bulk material or in a microcavity. The computational models developed in this thesis are used to identify and characterize microcavities for potential use in a single-photon source. The computational tools developed are also used to investigate novel photonic crystal microcavities that incorporate 1D distributed Bragg reflectors for vertical confinement. It is found that the spontaneous emission enhancement in the quasi-3D cavities can be significantly greater than in traditional suspended slab

Ultrastrong exciton-photon coupling in single and coupled organic microcavities

Science.gov (United States)

Liu, Bin; Bramante, Rosemary; Valle, Brent; Singer, Kenneth; Khattab, Tawfik; Williams, Jarrod; Twieg, Robert

2015-03-01

We have demonstrated ultrastrong light-matter coupling in organic planar microcavities composed of a neat glassy organic dye film between two metallic (aluminum) mirrors in a half-cavity configuration. Such cavities are characterized by Q factors around 10. Tuning the thickness of the organic layer enables the observation of the ultrastrong coupling regime. Via reflectivity measurements, we observe a very large Rabi splitting around 1.227 eV between upper and lower polariton branches at room temperature, and we detect polariton emission from the lower polariton branch via photoluminescence measurements. The large splitting is due to the large oscillator strength of the neat dye glass, and to the match of the low-Q cavity spectral width to the broad absorption width of the dye film material. We also study the interaction between excitonic states of neat glassy organic dye and cavity modes within coupled microcavity structures. The high-reflectivity mirrors are formed from distributed Bragg reflectors (DBR), which are multilayer films fabricated using the coextrusion process, containing alternating layers of high (SAN25, n =1.57) and low (Dyneon THV 220G, n =1.37) refractive index dielectric polymers. Nonlinear optical measurements will be discussed. This research was supported by the National Science Foundation Center for Layered Polymer Systems (CLiPS) under Grant Number DMR-0423914.

Phonon-induced optical superlattice.

Science.gov (United States)

de Lima, M M; Hey, R; Santos, P V; Cantarero, A

2005-04-01

We demonstrate the formation of a dynamic optical superlattice through the modulation of a semiconductor microcavity by stimulated acoustic phonons. The high coherent phonon population produces a folded optical dispersion relation with well-defined energy gaps and renormalized energy levels, which are accessed using reflection and diffraction experiments.

The quantum dynamics of two qubits inside two distant microcavities connected via a single-mode optical fiber

International Nuclear Information System (INIS)

Nguyen, Van Hieu; Nguyen, Bich Ha; Duong, Hai Trieu

2010-01-01

For application to studying the transmission of quantum information, also called quantum communication, between two identical qubits placed inside two identical single-mode microcavities connected via a single-mode optical fiber, the time evolution of this system is investigated. In the Markovian approximation, the von Neumann equation for its reduced density matrix contains a completely positive linear operator called the Liouvillian operator describing the decoherence of this system due to its interaction with the environment. By using the Linblad formula for the Liouvillian operator, a system of rate equations can be derived. In the special case of resonance between the energy difference of two states in each qubit and the energy of the fiber mode, the rate equations for the system excited up to the first level are solved in first order approximation with respect to the decoherence constants. It is shown that when there is no decoherence, the perfect quantum state transmission between two qubits can take place if the physical parameters of the system satisfy definite conditions. A possible extension to studying the system excited to high energy states is also discussed

Spoked-ring microcavities: enabling seamless integration of nanophotonics in unmodified advanced CMOS microelectronics chips

Science.gov (United States)

Wade, Mark T.; Shainline, Jeffrey M.; Orcutt, Jason S.; Ram, Rajeev J.; Stojanovic, Vladimir; Popovic, Milos A.

2014-03-01

We present the spoked-ring microcavity, a nanophotonic building block enabling energy-efficient, active photonics in unmodified, advanced CMOS microelectronics processes. The cavity is realized in the IBM 45nm SOI CMOS process - the same process used to make many commercially available microprocessors including the IBM Power7 and Sony Playstation 3 processors. In advanced SOI CMOS processes, no partial etch steps and no vertical junctions are available, which limits the types of optical cavities that can be used for active nanophotonics. To enable efficient active devices with no process modifications, we designed a novel spoked-ring microcavity which is fully compatible with the constraints of the process. As a modulator, the device leverages the sub-100nm lithography resolution of the process to create radially extending p-n junctions, providing high optical fill factor depletion-mode modulation and thereby eliminating the need for a vertical junction. The device is made entirely in the transistor active layer, low-loss crystalline silicon, which eliminates the need for a partial etch commonly used to create ridge cavities. In this work, we present the full optical and electrical design of the cavity including rigorous mode solver and FDTD simulations to design the Qlimiting electrical contacts and the coupling/excitation. We address the layout of active photonics within the mask set of a standard advanced CMOS process and show that high-performance photonic devices can be seamlessly monolithically integrated alongside electronics on the same chip. The present designs enable monolithically integrated optoelectronic transceivers on a single advanced CMOS chip, without requiring any process changes, enabling the penetration of photonics into the microprocessor.

Stimulated secondary emission from semiconductor microcavities

DEFF Research Database (Denmark)

Østergaard, John Erland; Mizeikis, V.; Langbein, Wolfgang Werner

2001-01-01

We find strong influence of final-state stimulation on the time-resolved light emission dynamics from semiconductor microcavities after pulsed excitation allowing angle-resonant polariton-polariton scattering on the lower-polariton branch. The polariton dynamics can be controlled by injection...

Whispering gallery mode emission from a composite system of J-aggregates and photonic microcavity

Energy Technology Data Exchange (ETDEWEB)

Melnikau, Dzmitry; Savateeva, Diana [Centro de Física de Materiales (MPC, CSIC-UPV/EHU) and Donostia International Physics Center (DIPC), Po Manuel de Lardizabal 5, Donostia, San Sebastian 20018 (Spain); Rusakov, Konstantin I. [Department of Physics, Brest State Technical University, Brest 224017 (Belarus); Rakovich, Yury P., E-mail: Yury.Rakovich@ehu.es [Centro de Física de Materiales (MPC, CSIC-UPV/EHU) and Donostia International Physics Center (DIPC), Po Manuel de Lardizabal 5, Donostia, San Sebastian 20018 (Spain); IKERBASQUE, Basque Foundation for Science, Bilbao (Spain)

2014-01-15

We report on development and characterization of Whispering Gallery Modes spherical microcavities integrated with organic dye molecules in a J-aggregate state. The microcavities are studied using micro-photoluminescence spectroscopy, and fluorescence lifetime imaging confocal microscopy. Directional emission of light from the microcavity is also experimentally demonstrated and attributed to the photonic jets generated in the microsphere. -- Highlights: • Report on the development and characterization of hybrid system consisting of thin shell of J-aggregates and spherical Whispering Gallery Mode microcavity. • An investigation of spontaneous emission rate in the shell of J-aggregates integrated with a Whispering Gallery Mode cavity. • Demonstration of directional emission from Whispering Gallery Mode cavity with J-aggregates which is highly desirable functionality for both micro- and nano-scale cavities.

Dynamical Fano-Like Interference between Rabi Oscillations and Coherent Phonons in a Semiconductor Microcavity System.

Science.gov (United States)

Yoshino, S; Oohata, G; Mizoguchi, K

2015-10-09

We report on dynamical interference between short-lived Rabi oscillations and long-lived coherent phonons in CuCl semiconductor microcavities resulting from the coupling between the two oscillations. The Fourier-transformed spectra of the time-domain signals obtained from semiconductor microcavities by using a pump-probe technique show that the intensity of the coherent longitudinal optical phonon of CuCl is enhanced by increasing that of the Rabi oscillation, which indicates that the coherent phonon is driven by the Rabi oscillation through the Fröhlich interaction. Moreover, as the Rabi oscillation frequency decreases upon crossing the phonon frequency, the spectral profile of the coherent phonon changes from a peak to a dip with an asymmetric structure. The continuous wavelet transformation reveals that these peak and dip structures originate from constructive and destructive interference between Rabi oscillations and coherent phonons, respectively. We demonstrate that the asymmetric spectral structures in relation to the frequency detuning are well reproduced by using a classical coupled oscillator model on the basis of dynamical Fano-like interference.

Dynamics of polaritons in semiconductor microcavities near instability thresholds

International Nuclear Information System (INIS)

He, Peng-Bin

2012-01-01

A theoretical study is presented on the dynamics of polaritons in semiconductor microcavities near parametric instability thresholds. With upward or downward ramp of optical pump, different instability modes emerge in parameter space defined by damping and detuning. According to these modes, stationary short-wave, stationary periodic, oscillatory periodic, and oscillatory uniform parametric instabilities are distinguished. By multiple scale expansion, the dynamics near threshold can be described by a critical mode with a slowly varying amplitude for the last three instabilities. Furthermore, it is found that the evolutions of their amplitudes are governed by real or complex Ginzburg–Landau equations. -- Highlights: ► Phase diagrams for different instability in extended parameter space. ► Different instability modes near thresholds. ► Different envelop equations near thresholds obtained by multi-scale expansion.

High quality factor GaAs microcavity with buried bullseye defects

Science.gov (United States)

Winkler, K.; Gregersen, N.; Häyrynen, T.; Bradel, B.; Schade, A.; Emmerling, M.; Kamp, M.; Höfling, S.; Schneider, C.

2018-05-01

The development of high quality factor solid-state microcavities with low mode volumes has paved the way towards on-chip cavity quantum electrodynamics experiments and the development of high-performance nanophotonic devices. Here, we report on the implementation of a new kind of solid-state vertical microcavity, which allows for confinement of the electromagnetic field in the lateral direction without deep etching. The confinement originates from a local elongation of the cavity layer imprinted in a shallow etch and epitaxial overgrowth technique. We show that it is possible to improve the quality factor of such microcavities by a specific in-plane bullseye geometry consisting of a set of concentric rings with subwavelength dimensions. This design results in a smooth effective lateral photonic potential and therefore in a reduction of lateral scattering losses, which makes it highly appealing for experiments in the framework of exciton-polariton physics demanding tight spatial confinement.

A study of the cavity polariton under strong excitation:dynamics and nonlinearities in II-VI micro-cavities

International Nuclear Information System (INIS)

Muller, Markus

2000-01-01

This work contains an experimental study of the photoluminescence dynamics of cavity polaritons in strong coupling micro-cavities based on II-VI semiconductor compounds. The small exciton size and the strong exciton binding energy in these materials allowed us to study the strong coupling regime between photon and exciton up to high excitation densities, exploring the linear and non-linear emission regimes. Our main experimental techniques are picosecond time-resolved and angular photoluminescence spectroscopy. In the linear regime and for a negative photon-exciton detuning, we observe a suppression of the polariton relaxation by the emission of acoustic phonons leading to a non-equilibrium polariton distribution on the lower branch. This 'bottleneck' effect, which has already been described for polaritons in bulk semiconductors, results from the pronounced photon like character of the polaritons near k(parallel) = 0 in this configuration. At high excitation densities, non-linear relaxation processes, namely final state stimulation of the relaxation and polariton-polariton scattering, bypass this bottleneck giving rise to a very rapid relaxation down to the bottom of the band. We show that this dramatic change in the relaxation dynamics is finally responsible of the super-linear increase of the polariton emission from these states. (author) [fr

Composite modulation of Fano resonance in plasmonic microstructures by electric-field and microcavity

International Nuclear Information System (INIS)

Zhang, Fan; Wu, Chenyun; Yang, Hong; Hu, Xiaoyong; Gong, Qihuang

2014-01-01

Composite modulation of Fano resonance by using electric-field and microcavity simultaneously is realized in a plasmonic microstructure, which consists of a gold nanowire grating inserted into a Fabry-Perot microcavity composited of a liquid crystal layer sandwiched between two indium tin oxide layers. The Fano resonance wavelength varies with the applied voltage and the microcavity resonance. A large shift of 48 nm in the Fano resonance wavelength is achieved when the applied voltage is 20 V. This may provide a new way for the study of multi-functional integrated photonic circuits and chips based on plasmonic microstructures

Composite modulation of Fano resonance in plasmonic microstructures by electric-field and microcavity

Energy Technology Data Exchange (ETDEWEB)

Zhang, Fan; Wu, Chenyun; Yang, Hong [State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871 (China); Hu, Xiaoyong, E-mail: xiaoyonghu@pku.edu.cn; Gong, Qihuang [State Key Laboratory for Mesoscopic Physics and Department of Physics, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100871 (China)

2014-11-03

Composite modulation of Fano resonance by using electric-field and microcavity simultaneously is realized in a plasmonic microstructure, which consists of a gold nanowire grating inserted into a Fabry-Perot microcavity composited of a liquid crystal layer sandwiched between two indium tin oxide layers. The Fano resonance wavelength varies with the applied voltage and the microcavity resonance. A large shift of 48 nm in the Fano resonance wavelength is achieved when the applied voltage is 20 V. This may provide a new way for the study of multi-functional integrated photonic circuits and chips based on plasmonic microstructures.

Optimisation of spontaneous four-wave mixing in a ring microcavity

Science.gov (United States)

Chuprina, I. N.; An, P. P.; Zubkova, E. G.; Kovalyuk, V. V.; Kalachev, A. A.; Gol'tsman, G. N.

2017-11-01

A theory of spontaneous four-wave mixing in a ring microcavity is developed. The rate of emission of biphotons for pulsed and monochromatic pumping with allowance for the dispersion of group velocities is analytically calculated. In the first case, pulses in the form of an increasing exponential are considered, which are optimal for excitation of an individual resonator mode. The behaviour of the group velocity dispersion as a function of the width and height of the waveguide is studied for a specific case of a ring microcavity made of silicon nitride. The results of the numerical calculation are in good agreement with the experimental data. The ring microcavity is made of two types of waveguides: completely etched and half etched. It is found that the latter allow for better control over the parameters in the manufacturing process, making them more predictable. Presented at the Russian - British Symposium on Quantum Technologies (Moscow, 20 - 23 March 2017)

Proposal for efficient mode converter based on cavity quantum electrodynamics dark mode in a semiconductor quantum dot coupled to a bimodal microcavity

Energy Technology Data Exchange (ETDEWEB)

Li, Jiahua [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Key Laboratory of Fundamental Physical Quantities Measurement of Ministry of Education, Wuhan 430074 (China); Yu, Rong, E-mail: yurong321@126.com [School of Science, Hubei Province Key Laboratory of Intelligent Robot, Wuhan Institute of Technology, Wuhan 430073 (China); Ma, Jinyong; Wu, Ying, E-mail: yingwu2@163.com [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

2014-10-28

The ability to engineer and convert photons between different modes in a solid-state approach has extensive technological implications not only for classical communication systems but also for future quantum networks. In this paper, we put forward a scheme for coherent mode conversion of optical photons by utilizing the intermediate coupling between a single quantum dot and a bimodal photonic crystal microcavity via a waveguide. Here, one mode of the photonic crystal microcavity is coherently driven by an external single-frequency continuous-wave laser field and the two cavity modes are not coupled to each other due to their orthogonal polarizations. The undriven cavity mode is thus not directly coupled to the input driving laser and the only way it can get light is via the quantum dot. The influences of the system parameters on the photon-conversion efficiency are analyzed in detail in the limit of weak probe field and it is found that high photon-conversion efficiency can be achieved under appropriate conditions. It is shown that the cavity dark mode, which is a superposition of the two optical modes and is decoupled from the quantum dot, can appear in such a hybrid optical system. We discuss the properties of the dark mode and indicate that the formation of the dark mode enables the efficient transfer of optical fields between the two cavity modes.

Research on the Band Gap Characteristics of Two-Dimensional Phononic Crystals Microcavity with Local Resonant Structure

Directory of Open Access Journals (Sweden)

Mao Liu

2015-01-01

Full Text Available A new two-dimensional locally resonant phononic crystal with microcavity structure is proposed. The acoustic wave band gap characteristics of this new structure are studied using finite element method. At the same time, the corresponding displacement eigenmodes of the band edges of the lowest band gap and the transmission spectrum are calculated. The results proved that phononic crystals with microcavity structure exhibited complete band gaps in low-frequency range. The eigenfrequency of the lower edge of the first gap is lower than no microcavity structure. However, for no microcavity structure type of quadrilateral phononic crystal plate, the second band gap disappeared and the frequency range of the first band gap is relatively narrow. The main reason for appearing low-frequency band gaps is that the proposed phononic crystal introduced the local resonant microcavity structure. This study provides a good support for engineering application such as low-frequency vibration attenuation and noise control.

Homoepitaxial nonpolar (10-10) ZnO/ZnMgO monolithic microcavities: Towards reduced photonic disorder

International Nuclear Information System (INIS)

Zuniga-Perez, J.; Kappei, L.; Deparis, C.; Chenot, S.; Leroux, M.; Reveret, F.; Jamadi, O.; Leymarie, J.; Grundmann, M.; Prado, E. de

2016-01-01

Nonpolar ZnO/ZnMgO-based optical microcavities have been grown on (10-10) m-plane ZnO substrates by plasma-assisted molecular beam epitaxy. Reflectivity measurements indicate an exponential increase of the cavity quality factor with the number of layers in the distributed Bragg reflectors. Most importantly, microreflectivity spectra recorded with a spot size in the order of 2 μm show a negligible photonic disorder (well below 1 meV), leading to local quality factors equivalent to those obtained by macroreflectivity. The anisotropic character of the nonpolar heterostructures manifests itself both in the surface features, elongated parallel to the in-plane c direction, and in the optical spectra, with two cavity modes being observed at different energies for orthogonal polarizations.

Homoepitaxial nonpolar (10-10) ZnO/ZnMgO monolithic microcavities: Towards reduced photonic disorder

Energy Technology Data Exchange (ETDEWEB)

Zuniga-Perez, J., E-mail: jzp@crhea.cnrs.fr; Kappei, L.; Deparis, C.; Chenot, S.; Leroux, M. [CRHEA-CNRS, Rue Bernard Gregory, 06560 Valbonne (France); Reveret, F.; Jamadi, O.; Leymarie, J. [Clermont Université, Institut Pascal (IP), BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6602, IP, F-63171 Aubière (France); Grundmann, M. [CRHEA-CNRS, Rue Bernard Gregory, 06560 Valbonne (France); Institut für Experimentelle Physik II, Fakultät für Physik und Geowissenschaften, Universität Leipzig, Linnestr. 5, 04103 Leipzig (Germany); Prado, E. de [CRHEA-CNRS, Rue Bernard Gregory, 06560 Valbonne (France); Departamento de Física Aplicada y Electromagnetismo, Universitat de Valencia, c/Dr Moliner 50, Burjassot, Valencia 46100 (Spain)

2016-06-20

Nonpolar ZnO/ZnMgO-based optical microcavities have been grown on (10-10) m-plane ZnO substrates by plasma-assisted molecular beam epitaxy. Reflectivity measurements indicate an exponential increase of the cavity quality factor with the number of layers in the distributed Bragg reflectors. Most importantly, microreflectivity spectra recorded with a spot size in the order of 2 μm show a negligible photonic disorder (well below 1 meV), leading to local quality factors equivalent to those obtained by macroreflectivity. The anisotropic character of the nonpolar heterostructures manifests itself both in the surface features, elongated parallel to the in-plane c direction, and in the optical spectra, with two cavity modes being observed at different energies for orthogonal polarizations.

Optical properties of semiconductors quantum microcavity structures

International Nuclear Information System (INIS)

Afshar, A.M.

1996-12-01

The principal phenomenon investigated in this thesis is vacuum Rabi coupling in semiconductor microcavity structures. In these structures quantum well excitons are embedded in a Fabry - Perot like cavity, defined by two semiconductor dielectric mirrors. In such a system the coupled exciton and cavity photon mode form a mixed - mode polariton, where on - resonance there are two branches, each having 50% exciton and 50% photon character. The separation between the upper and lower branches is a measure of the coupling strength where the strength is dependent on the exciton oscillator strength. This interaction is known as vacuum Rabi coupling, and clear anticrossing is seen when the exciton is tuned through the cavity. In our reflectivity experiments we demonstrate control of the coupling between the cavity mode and the exciton by varying temperature, applied electric or magnetic field. Modelling of the reflectivity spectra and the tuning was done using a Transfer Matrix Reflectivity (TMR) model or a linear dispersion model, where in both cases the excitons are treated as Lorentz oscillators. Temperature tuning is achieved because exciton energy decreases with temperature at a much faster rate than the cavity mode. We have demonstrated vacuum Rabi coupling of the cavity mode with both the heavy - hole and light - hole excitons. Electric field tuning is achieved via the quantum confined Stark effect which decreases the exciton energy with increasing field, whilst at the same time the cavity mode energy remains constant. A study of how the electric field reduction of exciton oscillator strength reduces the vacuum Rabi coupling strength is performed. We report the first observation in a semiconductor structure of motional narrowing, seen in both electric field and in temperature tuning experiments at high magnetic field. In magnetic field studies we show how magnetic field induced increase in exciton oscillator strength affects the vacuum Rabi coupling. We also show by

Room temperature strong coupling effects from single ZnO nanowire microcavity

KAUST Repository

Das, Ayan

2012-05-01

Strong coupling effects in a dielectric microcavity with a single ZnO nanowire embedded in it have been investigated at room temperature. A large Rabi splitting of ?100 meV is obtained from the polariton dispersion and a non-linearity in the polariton emission characteristics is observed at room temperature with a low threshold of 1.63 ?J/cm2, which corresponds to a polariton density an order of magnitude smaller than that for the Mott transition. The momentum distribution of the lower polaritons shows evidence of dynamic condensation and the absence of a relaxation bottleneck. The polariton relaxation dynamics were investigated by timeresolved measurements, which showed a progressive decrease in the polariton relaxation time with increase in polariton density. © 2012 Optical Society of America.

Purcell effect in an organic-inorganic halide perovskite semiconductor microcavity system

International Nuclear Information System (INIS)

Wang, Jun; Wang, Yafeng; Hu, Tao; Wu, Lin; Shen, Xuechu; Chen, Zhanghai; Cao, Runan; Xu, Fei; Da, Peimei; Zheng, Gengfeng; Lu, Jian

2016-01-01

Organic-inorganic halide perovskite semiconductors with the attractive physics properties, including strong photoluminescence (PL), huge oscillator strengths, and low nonradiative recombination losses, are ideal candidates for studying the light-matter interaction in nanostructures. Here, we demonstrate the coupling of the exciton state and the cavity mode in the lead halide perovskite microcavity system at room temperature. The Purcell effect in the coupling system is clearly observed by using angle-resolved photoluminescence spectra. Kinetic analysis based on time-resolved PL reveals that the spontaneous emission rate of the halide perovskite semiconductor is significantly enhanced at resonance of the exciton energy and the cavity mode. Our results provide the way for developing electrically driven organic polariton lasers, optical devices, and on-chip coherent quantum light sources

Continuous-wave optically pumped green perovskite vertical-cavity surface-emitter

KAUST Repository

Alias, Mohd Sharizal

2017-09-11

We report an optically pumped green perovskite vertical-cavity surface-emitter operating in continuous-wave (CW) with a power density threshold of ~89 kW/cm2. The device has an active region of CH3NH3PbBr3 embedded in a dielectric microcavity; this feat was achieved with a combination of optimal spectral alignment of the optical cavity modes with the perovskite optical gain, an adequate Q-factor of the microcavity, adequate thermal stability, and improved material quality with a smooth, passivated, and annealed thin active layer. Our results signify a way towards efficient CW perovskite emitter operation and electrical injection using low-cost fabrication methods for addressing monolithic optoelectronic integration and lasing in the green gap.

Ultranarrow polaritons in a semiconductor microcavity

DEFF Research Database (Denmark)

Jensen, Jacob Riis; Borri, Paola; Langbein, Wolfgang

2000-01-01

We have achieved a record high ratio (19) of the Rabi splitting (3.6 meV) to the polariton linewidth (190 mu eV), in a semiconductor lambda microcavity with a single 25 nm GaAs quantum well at the antinode. The narrow polariton lines are obtained with a special cavity design which reduces...

Self-Cleaning Microcavity Array for Photovoltaic Modules.

Science.gov (United States)

Vüllers, Felix; Fritz, Benjamin; Roslizar, Aiman; Striegel, Andreas; Guttmann, Markus; Richards, Bryce S; Hölscher, Hendrik; Gomard, Guillaume; Klampaftis, Efthymios; Kavalenka, Maryna N

2018-01-24

Development of self-cleaning coatings is of great interest for the photovoltaic (PV) industry, as soiling of the modules can significantly reduce their electrical output and increase operational costs. We fabricated flexible polymeric films with novel disordered microcavity array (MCA) topography from fluorinated ethylene propylene (FEP) by hot embossing. Because of their superhydrophobicity with water contact angles above 150° and roll-off angles below 5°, the films possess self-cleaning properties over a wide range of tilt angles, starting at 10°, and contaminant sizes (30-900 μm). Droplets that impact the FEP MCA surface with velocities of the same order of magnitude as that of rain bounce off the surface without impairing its wetting properties. Additionally, the disordered MCA topography of the films enhances the performance of PV devices by improving light incoupling. Optical coupling of the FEP MCA films to a glass-encapsulated multicrystalline silicon solar cell results in 4.6% enhancement of the electrical output compared to that of an uncoated device.

Quantum optics with quantum dots in photonic nanowires

DEFF Research Database (Denmark)

Claudon, Julien; Munsch, Matthieu; Bleuse, Joel

2012-01-01

Besides microcavities and photonic crystals, photonic nanowires have recently emerged as a novel resource for solidstate quantum optics. We will review recent studies which demonstrate an excellent control over the spontaneous emission of InAs quantum dots (QDs) embedded in single-mode Ga...... quantum optoelectronic devices. Quite amazingly, this approach has for instance permitted (unlike microcavity-based approaches) to combine for the first time a record-high efficiency (72%) and a negligible g(2) in a QD single photon source....

Rayleigh scattering in coupled microcavities: theory.

Science.gov (United States)

Vörös, Zoltán; Weihs, Gregor

2014-12-03

In this paper we theoretically study how structural disorder in coupled semiconductor heterostructures influences single-particle scattering events that would otherwise be forbidden by symmetry. We extend the model of Savona (2007 J. Phys.: Condens. Matter 19 295208) to describe Rayleigh scattering in coupled planar microcavity structures, and find that effective filter theories can be ruled out.

Solid state microcavity dye lasers fabricated by nanoimprint lithography

DEFF Research Database (Denmark)

Nilsson, Daniel; Nielsen, Theodor; Kristensen, Anders

2004-01-01

propagating TE–TM modes. The laser cavity has the lateral shape of a trapezoid, supporting lasing modes by reflection on the vertical cavity walls. The solid polymer dye lasers emit laterally through one of the vertical cavity walls, when pumped optically through the top surface by means of a frequency...... doubled, pulsed Nd:YAG laser. Lasing in the wavelength region from 560 to 570 nm is observed from a laser with a side-length of 50 µm. In this proof of concept, the lasers are multimode with a mode wavelength separation of approximately 1.6 nm, as determined by the waveguide propagation constant......We present a solid state polymer microcavity dye laser, fabricated by thermal nanoimprint lithography (NIL) in a dye-doped thermoplast. The thermoplast poly-methylmethacrylate (PMMA) is used due to its high transparency in the visible range and its robustness to laser radiation. The laser dye...

Ultrastrong light-matter coupling in electrically doped microcavity organic light emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Mazzeo, M., E-mail: marco.mazzeo@unisalento.it [Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento, Via Monteroni, 73100 Lecce (Italy); NNL, Istituto Nanoscienze - CNR, Via Arnesano, 73100 Lecce (Italy); Genco, A. [Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento, Via Monteroni, 73100 Lecce (Italy); Gambino, S. [NNL, Istituto Nanoscienze - CNR, Via Arnesano, 73100 Lecce (Italy); CBN, Istituto Italiano Tecnologia, Via Barsanti 1, 73010 Lecce (Italy); Ballarini, D.; Mangione, F.; Sanvitto, D. [NNL, Istituto Nanoscienze - CNR, Via Arnesano, 73100 Lecce (Italy); Di Stefano, O.; Patanè, S.; Savasta, S. [Dipartimento di Fisica e Scienze della Terra, Università di Messina, Viale F. Stagno d' Alcontres 31, 98166 Messina (Italy); Gigli, G. [Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento, Via Monteroni, 73100 Lecce (Italy); NNL, Istituto Nanoscienze - CNR, Via Arnesano, 73100 Lecce (Italy); CBN, Istituto Italiano Tecnologia, Via Barsanti 1, 73010 Lecce (Italy)

2014-06-09

The coupling of the electromagnetic field with an electronic transition gives rise, for strong enough light-matter interactions, to hybrid states called exciton-polaritons. When the energy exchanged between light and matter becomes a significant fraction of the material transition energy an extreme optical regime called ultrastrong coupling (USC) is achieved. We report a microcavity embedded p-i-n monolithic organic light emitting diode working in USC, employing a thin film of squaraine dye as active layer. A normalized coupling ratio of 30% has been achieved at room temperature. These USC devices exhibit a dispersion-less angle-resolved electroluminescence that can be exploited for the realization of innovative optoelectronic devices. Our results may open the way towards electrically pumped polariton lasers.

Limulus amoebocyte lysate test via an open-microcavity optical biosensor

Science.gov (United States)

Scudder, Jonathan; Ye, Jing Yong

2018-02-01

Almost since its discovery, Limulus amoebocyte lysate (LAL) testing has been an important part of the pharmaceutical quality control toolkit. It allows for in vitro endotoxin testing, which has replaced tests using animals, such as using rabbits' thermal response to judge pyrogenicity of test samples, thus leading to a less expensive and faster test of parenteral pharmaceuticals and medical devices that contact blood or cerebrospinal fluid. However, limited by the detection mechanisms of the LAL assays currently used in industry, further improvement in their performance is challenging. To address the growing demand on optimizing LAL assays for increased test sensitivity and reduced assay time, we have developed an LAL assay approach based on a detection mechanism that is different from those being used in industry, namely, gel-clot, turbidimetric, and chromogenic detection. Using a unique open-microcavity photonic-crystal biosensor to monitor the change in the refractive index due to the reaction between LAL regents and endotoxins, we have demonstrated that this approach has improved the LAL assay sensitivity by 200 times compared with the commercial standard methods, reduced the time needed for the assay by more than half, and eliminated the necessity to incubate the test samples. This study opens up the possibility of using the significantly improved LAL assays for a wide range of applications.

Directional Secondary Emission of a Semiconductor Microcavity

DEFF Research Database (Denmark)

Langbein, Wolfgang; Jensen, Jacob Riis; Hvam, Jørn Märcher

2000-01-01

We investigate the time-resolved secondary emission of a homogeneously broadened microcavity after resonant excitation. The sample consists of a 25nm GaAs single quantum well (QW) in the center of a wedged ¥ë cavity with AlAs/AlGaAs Bragg reflectors, grown by molecular beam epitaxy. At zero detun...

Weak-microcavity organic light-emitting diodes with improved light out-coupling.

Science.gov (United States)

Cho, Sang-Hwan; Song, Young-Woo; Lee, Joon-gu; Kim, Yoon-Chang; Lee, Jong Hyuk; Ha, Jaeheung; Oh, Jong-Suk; Lee, So Young; Lee, Sun Young; Hwang, Kyu Hwan; Zang, Dong-Sik; Lee, Yong-Hee

2008-08-18

We propose and demonstrate weak-microcavity organic light-emitting diode (OLED) displays with improved light-extraction and viewing-angle characteristics. A single pair of low- and high-index layers is inserted between indium tin oxide (ITO) and a glass substrate. The electroluminescent (EL) efficiencies of discrete red, green, and blue weak-microcavity OLEDs are enhanced by 56%, 107%, and 26%, respectively, with improved color purity. Moreover, full-color passive-matrix bottom-emitting OLED displays are fabricated by employing low-index layers of two thicknesses. As a display, the EL efficiency of white color was 27% higher than that of a conventional OLED display.

Voltage-controlled colour-tunable microcavity OLEDs with enhanced colour purity

International Nuclear Information System (INIS)

Choy, Wallace C H; Niu, J H; Li, W L; Chui, P C

2008-01-01

The emission spectrum of single-unit voltage-controlled colour-tunable organic light emitting devices (OLEDs) has been theoretically and experimentally studied. Our results show that by introducing the microcavity structure, the colour purity of not only the destination colour but also the colour-tunable route can be enhanced, while colour purity is still an issue in typical single-unit voltage-controlled colour-tunable OLEDs. With the consideration of the periodical cycling of resonant wavelength and absorption loss of the metal electrodes, the appropriate change in the thickness of the microcavity structure has been utilized to achieve voltage-controlled red-to-green and red-to-blue colour-tunable OLEDs without adding dyes or other organic materials to the OLEDs

Substantial enhancement of red emission intensity by embedding Eu-doped GaN into a microcavity

NARCIS (Netherlands)

Inaba, T.; Lee, D.-G.; Wakamatsu, R.; Kojima, T.; Mitchell, B.; Capretti, A.; Gregorkiewicz, T.; Koizumi, A.; Fujiwara, Y.

2016-01-01

We investigate resonantly excited photoluminescence from a Eu,O-codoped GaN layer embedded into a microcavity, consisting of an AlGaN/GaN distributed Bragg reflector and a Ag reflecting mirror. The microcavity is responsible for a 18.6-fold increase of the Eu emission intensity at ∼10K, and a

Micro-Cavity Fluidic Dye Laser

DEFF Research Database (Denmark)

Helbo, Bjarne; Kristensen, Anders; Menon, Aric Kumaran

2003-01-01

We have successfully designed, fabricated and characterized a micro-cavity fluidic dye laser with metallic mirrors, which can be integrated with polymer based lab-on-a-chip microsystems without further processing steps. A simple rate-equation model is used to predict the average pumping power...... threshold for lasing as function of cavity-mirror reflectance, laser dye concentration and cavity length. The laser device is characterized using the laser dye Rhodamine 6G dissolved in ethanol. Lasing is observed, and the influence of dye concentration is investigated....

Efficient analysis of mode profiles in elliptical microcavity using dynamic-thermal electron-quantum medium FDTD method.

Science.gov (United States)

Khoo, E H; Ahmed, I; Goh, R S M; Lee, K H; Hung, T G G; Li, E P

2013-03-11

The dynamic-thermal electron-quantum medium finite-difference time-domain (DTEQM-FDTD) method is used for efficient analysis of mode profile in elliptical microcavity. The resonance peak of the elliptical microcavity is studied by varying the length ratio. It is observed that at some length ratios, cavity mode is excited instead of whispering gallery mode. This depicts that mode profiles are length ratio dependent. Through the implementation of the DTEQM-FDTD on graphic processing unit (GPU), the simulation time is reduced by 300 times as compared to the CPU. This leads to an efficient optimization approach to design microcavity lasers for wide range of applications in photonic integrated circuits.

Interference effect in the resonant emission of a semiconductor microcavity

Science.gov (United States)

Cassabois, G.; Bogani, F.; Triques, A. L.; Delalande, C.; Roussignol, Ph.

2001-07-01

We present a phenomenological description of the coherent emission from a semiconductor microcavity in the strong-coupling regime. We consider two main contributions which are calculated in the framework of the semiclassical approach of the linear dispersion theory: reflectivity corresponds to the response of a uniform microcavity while resonant Rayleigh scattering (RRS) arises from disorder. Our simulations are compared to experimental results obtained at normal incidence in a backscattering geometry by means of cw spectroscopy and interferometric correlation with subpicosecond resolution. In this geometry, a fair agreement is reached assuming interferences between the two aforementioned contributions. This interference effect gives evidence of the drastic modification of the RRS emission pattern of the embedded quantum well induced by the Fabry-Pérot cavity.

Photoluminescence from a Tb-doped photonic crystal microcavity for white light generation

International Nuclear Information System (INIS)

Li Yigang; Almeida, Rui M

2010-01-01

Terbium-doped one-dimensional triple microcavities have been prepared by sol-gel processing. The photoluminescence (PL) of Tb 3+ ions outside a microcavity structure, when excited by blue laser light at 488 nm, consisted of three distinct peaks at 542, 587 and 619 nm. When embedded in the microcavities, the three Tb 3+ PL peaks were enhanced, balanced and broadened by the photonic crystal structure and combined into a continuous broad band. An analysis in the CIE colour space showed that white light can be obtained by mixing the modified Tb 3+ PL with the blue exciting light, while this is impossible with the original PL profile. This novel technique may improve white light generation by enhancing and modifying the spontaneous emission of current phosphors. It may also lead to the development of new rare-earth phosphor materials based on 4f-4f transitions, able to generate white light more efficiently, via simpler and cheaper alternatives to the current phosphor compositions. A novel configuration to combine this kind of structure with a white light-emitting-diode (LED) is also proposed.

Optical performance of hybrid porous silicon-porous alumina multilayers

Science.gov (United States)

Cencha, L. G.; Antonio Hernández, C.; Forzani, L.; Urteaga, R.; Koropecki, R. R.

2018-05-01

In this work, we study the optical response of structures involving porous silicon and porous alumina in a multi-layered hybrid structure. We performed a rational design of the optimal sequence necessary to produce a high transmission and selective filter, with potential applications in chemical and biosensors. The combination of these porous materials can be used to exploit its distinguishing features, i.e., high transparency of alumina and high refractive index of porous silicon. We assembled hybrid microcavities with a central porous alumina layer between two porous silicon Bragg reflectors. In this way, we constructed a Fabry-Perot resonator with high reflectivity and low absorption that improves the quality of the filter compared to a microcavity built only with porous silicon or porous alumina. We explored a simpler design in which one of the Bragg reflectors is replaced by the aluminium that remains bound to the alumina after its fabrication. We theoretically explored the potential of the proposal and its limitations when considering the roughness of the layers. We found that the quality of a microcavity made entirely with porous silicon shows a limit in the visible range due to light absorption. This limitation is overcome in the hybrid scheme, with the roughness of the layers determining the ultimate quality. Q-factors of 220 are experimentally obtained for microcavities supported on aluminium, while Q-factors around 600 are reached for microcavities with double Bragg reflectors, centred at 560 nm. This represents a four-fold increase with respect to the optimal porous silicon microcavity at this wavelength.

Nonlinear Photonics and Novel Optical Phenomena

CERN Document Server

Morandotti, Roberto

2012-01-01

Nonlinear Photonics and Novel Optical Phenomena contains contributed chapters from leading experts in nonlinear optics and photonics, and provides a comprehensive survey of fundamental concepts as well as hot topics in current research on nonlinear optical waves and related novel phenomena. The book covers self-accelerating airy beams, integrated photonics based on high index doped-silica glass, linear and nonlinear spatial beam dynamics in photonic lattices and waveguide arrays, polariton solitons and localized structures in semiconductor microcavities, terahertz waves, and other novel phenomena in different nanophotonic and optical systems.

Silicon on-chip bandpass filters for the multiplexing of high sensitivity photonic crystal microcavity biosensors

International Nuclear Information System (INIS)

Yan, Hai; Zou, Yi; Yang, Chun-Ju; Chakravarty, Swapnajit; Wang, Zheng; Tang, Naimei; Chen, Ray T.; Fan, Donglei

2015-01-01

A method for the dense integration of high sensitivity photonic crystal (PC) waveguide based biosensors is proposed and experimentally demonstrated on a silicon platform. By connecting an additional PC waveguide filter to a PC microcavity sensor in series, a transmission passband is created, containing the resonances of the PC microcavity for sensing purpose. With proper engineering of the passband, multiple high sensitivity PC microcavity sensors can be integrated into microarrays and be interrogated simultaneously between a single input and a single output port. The concept was demonstrated with a 2-channel L55 PC biosensor array containing PC waveguide filters. The experiment showed that the sensors on both channels can be monitored simultaneously from a single output spectrum. Less than 3 dB extra loss for the additional PC waveguide filter is observed

Silicon on-chip bandpass filters for the multiplexing of high sensitivity photonic crystal microcavity biosensors

Energy Technology Data Exchange (ETDEWEB)

Yan, Hai, E-mail: hai.yan@utexas.edu; Zou, Yi; Yang, Chun-Ju [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States); Chakravarty, Swapnajit, E-mail: swapnajit.chakravarty@omegaoptics.com [Omega Optics, Inc., 8500 Shoal Creek Blvd., Austin, Texas 78757 (United States); Wang, Zheng [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States); Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712 (United States); Tang, Naimei; Chen, Ray T., E-mail: raychen@uts.cc.utexas.edu [Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, 10100 Burnet Rd., Austin, Texas 78758 (United States); Omega Optics, Inc., 8500 Shoal Creek Blvd., Austin, Texas 78757 (United States); Fan, Donglei [Materials Science and Engineering Program, Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712 (United States); Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States)

2015-03-23

A method for the dense integration of high sensitivity photonic crystal (PC) waveguide based biosensors is proposed and experimentally demonstrated on a silicon platform. By connecting an additional PC waveguide filter to a PC microcavity sensor in series, a transmission passband is created, containing the resonances of the PC microcavity for sensing purpose. With proper engineering of the passband, multiple high sensitivity PC microcavity sensors can be integrated into microarrays and be interrogated simultaneously between a single input and a single output port. The concept was demonstrated with a 2-channel L55 PC biosensor array containing PC waveguide filters. The experiment showed that the sensors on both channels can be monitored simultaneously from a single output spectrum. Less than 3 dB extra loss for the additional PC waveguide filter is observed.

Microcavity-Free Broadband Light Outcoupling Enhancement in Flexible Organic Light-Emitting Diodes with Nanostructured Transparent Metal-Dielectric Composite Electrodes.

Science.gov (United States)

Xu, Lu-Hai; Ou, Qing-Dong; Li, Yan-Qing; Zhang, Yi-Bo; Zhao, Xin-Dong; Xiang, Heng-Yang; Chen, Jing-De; Zhou, Lei; Lee, Shuit-Tong; Tang, Jian-Xin

2016-01-26

Flexible organic light-emitting diodes (OLEDs) hold great promise for future bendable display and curved lighting applications. One key challenge of high-performance flexible OLEDs is to develop new flexible transparent conductive electrodes with superior mechanical, electrical, and optical properties. Herein, an effective nanostructured metal/dielectric composite electrode on a plastic substrate is reported by combining a quasi-random outcoupling structure for broadband and angle-independent light outcoupling of white emission with an ultrathin metal alloy film for optimum optical transparency, electrical conduction, and mechanical flexibility. The microcavity effect and surface plasmonic loss can be remarkably reduced in white flexible OLEDs, resulting in a substantial increase in the external quantum efficiency and power efficiency to 47.2% and 112.4 lm W(-1).

Femtosecond coherent emission from GaAs bulk microcavities

Science.gov (United States)

Gurioli, Massimo; Bogani, Franco; Ceccherini, Simone; Colocci, Marcello; Beltram, Fabio; Sorba, Lucia

1999-02-01

The emission from a λ/2 GaAs bulk microcavity resonantly excited by femtosecond pulses has been characterized by using an interferometric correlation technique. It is found that the emission is dominated by the coherent signal due to light elastically scattered by disorder, and that scattering is predominantly originated from the lower polariton branch.

Experimental study of disorder in a semiconductor microcavity

Science.gov (United States)

Gurioli, M.; Bogani, F.; Wiersma, D. S.; Roussignol, Ph.; Cassabois, G.; Khitrova, G.; Gibbs, H.

2001-10-01

A detailed study of the structural disorder in wedge semiconductor microcavities (MC's) is presented. We demonstrate that images of the coherent emission from the MC surface can be used for a careful characterization of both intrinsic and extrinsic optical properties of semiconductor MC's. The polariton broadening can be measured directly, avoiding the well-known problem of inhomogeneous broadening due to the MC wedge. A statistical analysis of the spatial line shape of the images of the MC surface shows the presence of static disorder associated with dielectric fluctuations in the Bragg reflector. Moreover, the presence of local fluctuations of the effective cavity length can be detected with subnanometer resolution. The analysis of the resonant Rayleigh scattering (RRS) gives additional information on the origin of the disorder. We find that the RRS is dominated by the scattering of the photonic component of the MC polariton by disorder in the Bragg reflector. Also the RRS is strongly enhanced along the [110] and [11¯0] directions. This peculiar scattering pattern is attributed to misfit dislocations induced by the large thickness of the mismatched AlGaAs alloy in the Bragg mirrors.

Density matrix of strongly coupled quantum dot - microcavity system

International Nuclear Information System (INIS)

Nguyen Van Hop

2009-01-01

Any two-level quantum system can be used as a quantum bit (qubit) - the basic element of all devices and systems for quantum information and quantum computation. Recently it was proposed to study the strongly coupled system consisting of a two-level quantum dot and a monoenergetic photon gas in a microcavity-the strongly coupled quantum dot-microcavity (QD-MC) system for short, with the Jaynes-Cumming total Hamiltonian, for the application in the quantum information processing. Different approximations were applied in the theoretical study of this system. In this work, on the basis of the exact solution of the Schrodinger equation for this system without dissipation we derive the exact formulae for its density matrix. The realization of a qubit in this system is discussed. The solution of the system of rate equation for the strongly coupled QD-MC system in the presence of the interaction with the environment was also established in the first order approximation with respect to this interaction.

Extended Macroscopic Study of Dilute Gas Flow within a Microcavity

Directory of Open Access Journals (Sweden)

Mohamed Hssikou

2016-01-01

Full Text Available The behaviour of monatomic and dilute gas is studied in the slip and early transition regimes using the extended macroscopic theory. The gas is confined within a two-dimensional microcavity where the longitudinal sides are in the opposite motion with constant velocity ±Uw. The microcavity walls are kept at the uniform and reference temperature T0. Thus, the gas flow is transported only by the shear stress induced by the motion of upper and lower walls. From the macroscopic point of view, the regularized 13-moment equations of Grad, R13, are solved numerically. The macroscopic gas proprieties are studied for different values of the so-called Knudsen number (Kn, which gives the gas-rarefaction degree. The results are compared with those obtained using the classical continuum theory of Navier-Stokes and Fourier (NSF.

Spectral tuning of lasing emission from optofluidic droplet microlasers using optical stretching

Czech Academy of Sciences Publication Activity Database

Aas, M.; Jonáš, A.; Kiraz, A.; Ježek, Jan; Brzobohatý, Oto; Pilát, Zdeněk; Zemánek, Pavel

2013-01-01

Roč. 21, č. 18 (2013), s. 21380-21394 ISSN 1094-4087 R&D Projects: GA ČR GPP205/11/P294; GA MŠk ED0017/01/01; GA TA ČR TA03010642 Institutional support: RVO:68081731 Keywords : Microcavities * Dye lasers * Optical tweezers * Optical manipulation * Fluorescence, laser-induced Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.525, year: 2013

Non-exponential spontaneous emission dynamics for emitters in a time-dependent optical cavity

NARCIS (Netherlands)

Thyrrestrup Nielsen, Henri; Hartsuiker, A.; Gerard, J.M.; Vos, Willem L.

2013-01-01

We have theoretically studied the effect of deterministic temporal control of spontaneous emission in a dynamic optical microcavity. We propose a new paradigm in light emission: we envision an ensemble of two-level emitters in an environment where the local density of optical states is modified on a

High figure of merit ultra-compact 3-channel parallel-connected photonic crystal mini-hexagonal-H1 defect microcavity sensor array

Science.gov (United States)

Wang, Chunhong; Sun, Fujun; Fu, Zhongyuan; Ding, Zhaoxiang; Wang, Chao; Zhou, Jian; Wang, Jiawen; Tian, Huiping

2017-08-01

In this paper, a photonic crystal (PhC) butt-coupled mini-hexagonal-H1 defect (MHHD) microcavity sensor is proposed. The MHHD microcavity is designed by introducing six mini-holes into the initial H1 defect region. Further, based on a well-designed 1 ×3 PhC Beam Splitter and three optimal MHHD microcavity sensors with different lattice constants (a), a 3-channel parallel-connected PhC sensor array on monolithic silicon on insulator (SOI) is proposed. Finite-difference time-domain (FDTD) simulations method is performed to demonstrate the high performance of our structures. As statistics show, the quality factor (Q) of our optimal MHHD microcavity attains higher than 7×104, while the sensitivity (S) reaches up to 233 nm/RIU(RIU = refractive index unit). Thus, the figure of merit (FOM) >104 of the sensor is obtained, which is enhanced by two orders of magnitude compared to the previous butt-coupled sensors [1-4]. As for the 3-channel parallel-connected PhC MHHD microcavity sensor array, the FOMs of three independent MHHD microcavity sensors are 8071, 8250 and 8250, respectively. In addition, the total footprint of the proposed 3-channel parallel-connected PhC sensor array is ultra-compactness of 12.5 μm ×31 μm (width × length). Therefore, the proposed high FOM sensor array is an ideal platform for realizing ultra-compact highly parallel refractive index (RI) sensing.

High-Q submicron-diameter quantum-dot microcavity pillars for cavity QED experiments

DEFF Research Database (Denmark)

Gregersen, Niels; Lermer, Matthias; Dunzer, Florian

As/AlAs micropillar design where Bloch-wave engineering is employed to significally enhance the cavity mode confinement in the submicron diameter regime. We demonstrate a record-high vacuum Rabi splitting of 85 µeV of the strong coupling for pillars incorporating quantum dots with modest oscillator strength f ≈ 10....... It is well-known that light-matter interaction depends on the photonic environment, and thus proper engineering of the optical mode in microcavity systems is central to obtaining the desired functionality. In the strong coupling regime, the visibility of the Rabi splitting is described by the light...... coupling in micropillars relied on quantum dots with high oscillator strengths f > 50, our advanced design allows for the observation of strong coupling for submicron diameter quantum dot-pillars with standard f ≈ 10 oscillator strength. A quality factor of 13600 and a vacuum Rabi splitting of 85 µe...

Characterization of optical systems for the ALPS II experiment

International Nuclear Information System (INIS)

Spector, Aaron D.; Baehre, Robin; Willke, Benno; Hannover Univ.

2016-09-01

ALPS II is a light shining through a wall style experiment that will use the principle of resonant enhancement to boost the conversion and reconversion probabilities of photons to relativistic WISPs. This will require the use of long baseline low-loss optical cavities. Very high power build up factors in the cavities must be achieved in order to reach the design sensitivity of ALPS II. This necessitates a number of different sophisticated optical and control systems to maintain the resonance and ensure maximal coupling between the laser and the cavity. In this paper we report on the results of the characterization of these optical systems with a 20m cavity and discuss the results in the context of ALPS II.

Enhancing the Robustness of the Microcavity Coupling System

International Nuclear Information System (INIS)

Yan Ying-Zhan; Zhang Wen-Dong; Xiong Ji-Jun; Ji Zhe; Yan Shu-Bin; Liu Jun; Xue Chen-Yang

2011-01-01

A novel method to enhance the robustness of the microcavity coupling system (MCS) is presented by encapsulating and solidifying the MCS with a low refractive index (RI) curable UV polymer. The encapsulating process is illustrated in detail for a typical microsphere with a radius of R about 240μm. Three differences of the resonant characteristics before and after the package are observed and analyzed. The first two differences refer to the enhancement of the coupling strength and the shift of the resonant spectrum to the longer wavelength, which are both mainly because of the microsphere surrounding RI variation. Another difference is the quality factor (Q-factor) which decreases from 7.8×10 7 to 8.7×10 6 after the package due to the polymer absorption. Moreover, rotation testing experiments have been carried out to verify the robustness of the package MCS. Experimental results demonstrate that the packaged MCR has much better robust performance than the un-package sample. The enhancement of the robustness greatly promotes the microcavity research from fundamental investigations to application fields. (fundamental areas of phenomenology(including applications))

Hybrid quantum gates between flying photon and diamond nitrogen-vacancy centers assisted by optical microcavities

Science.gov (United States)

Wei, Hai-Rui; Lu Long, Gui

2015-01-01

Hybrid quantum gates hold great promise for quantum information processing since they preserve the advantages of different quantum systems. Here we present compact quantum circuits to deterministically implement controlled-NOT, Toffoli, and Fredkin gates between a flying photon qubit and diamond nitrogen-vacancy (NV) centers assisted by microcavities. The target qubits of these universal quantum gates are encoded on the spins of the electrons associated with the diamond NV centers and they have long coherence time for storing information, and the control qubit is encoded on the polarizations of the flying photon and can be easily manipulated. Our quantum circuits are compact, economic, and simple. Moreover, they do not require additional qubits. The complexity of our schemes for universal three-qubit gates is much reduced, compared to the synthesis with two-qubit entangling gates. These schemes have high fidelities and efficiencies, and they are feasible in experiment. PMID:26271899

High quality factor GaAs microcavity with buried bullseye defects

DEFF Research Database (Denmark)

Winkler, K.; Gregersen, Niels; Hayrynen, T.

2018-01-01

The development of high quality factor solid-state microcavities with low mode volumes has paved the way towards on-chip cavity quantum electrodynamics experiments and the development of high-performance nanophotonic devices. Here, we report on the implementation of a new kind of solid...

Optical properties of low-dimensional materials

CERN Document Server

Ogawa, T

1998-01-01

This book surveys recent theoretical and experimental studies of optical properties of low-dimensional materials. As an extended version of Optical Properties of Low-Dimensional Materials (Volume 1, published in 1995 by World Scientific), Volume 2 covers a wide range of interesting low-dimensional materials including both inorganic and organic systems, such as disordered polymers, deformable molecular crystals, dilute magnetic semiconductors, SiGe/Si short-period superlattices, GaAs quantum wires, semiconductor microcavities, and photonic crystals. There are excellent review articles by promis

Cavity switching : A novel resource for solid-state quantum optics

NARCIS (Netherlands)

Sattler, T.; Peinke, E.; Bleuse, J.; Claudon, J.; Vos, W. L.; Gerard, J.M.

2017-01-01

We present switching experiments performed on pillar microcavities containing a collection of quantum dots (QDs). Switching events are probed using QD luminescence, after ultrafast optical injection of free carriers. We observe large switching amplitudes (by as much as 20 linewidths), as well as

Room temperature strong coupling effects from single ZnO nanowire microcavity

KAUST Repository

Das, Ayan; Heo, Junseok; Bayraktaroglu, Adrian; Guo, Wei; Ng, Tien Khee; Phillips, Jamie; Ooi, Boon S.; Bhattacharya, Pallab

2012-01-01

Strong coupling effects in a dielectric microcavity with a single ZnO nanowire embedded in it have been investigated at room temperature. A large Rabi splitting of ?100 meV is obtained from the polariton dispersion and a non

Optical Control of Intersubband Absorption in a Multiple Quantum Well-Embedded Semiconductor Microcravity

Science.gov (United States)

Liu, Ansheng; Ning, Cun-Zheng

2000-01-01

Optical intersubband response of a multiple quantum well (MQW)-embedded microcavity driven by a coherent pump field is studied theoretically. The n-type doped MQW structure with three subbands in the conduction band is sandwiched between a semi-infinite medium and a distributed Bragg reflector (DBR). A strong pump field couples the two upper subbands and a weak field probes the two lower subbands. To describe the optical response of the MQW-embedded microcavity, we adopt a semi-classical nonlocal response theory. Taking into account the pump-probe interaction, we derive the probe-induced current density associated with intersubband transitions from the single-particle density-matrix formalism. By incorporating the current density into the Maxwell equation, we solve the probe local field exactly by means of Green's function technique and the transfer-matrix method. We obtain an exact expression for the probe absorption coefficient of the microcavity. For a GaAs/Al(sub x)Ga(sub 1-x)As MQW structure sandwiched between a GaAs/AlAs DBR and vacuum, we performed numerical calculations of the probe absorption spectra for different parameters such as pump intensity, pump detuning, and cavity length. We find that the probe spectrum is strongly dependent on these parameters. In particular, we find that the combination of the cavity effect and the Autler-Townes effect results in a triplet in the optical spectrum of the MQW system. The optical absorption peak value and its location can be feasibly controlled by varying the pump intensity and detuning.

High-power microcavity lasers based on highly erbium-doped sol-gel aluminosilicate glasses

International Nuclear Information System (INIS)

Le Ngoc Chung; Chu Thi Thu Ha; Nguyen Thu Trang; Pham Thu Nga; Pham Van Hoi; Bui Van Thien

2006-01-01

High-power whispering-gallery-mode (WGM) lasing from highly erbium-doped sol-gel aluminosilicate microsphere cavity coupled to a half-tapered optical fiber is presented. The lasing output power as high as 0.45 mW (-3.5 dBm) was obtained from sol-gel glass microsphere cavity with diameters in the range of 40-150 μm. The sol-gel method for making highly concentration Er-doped aluminosilicate glasses with Er-ion concentrations from 0.125 to 0.65 mol% of Er 3+ is described. Controlling collected lasing wavelength at each WGM is possible by adjusting the distance between the half-taper fiber and the microcavity and by diameter of the waist of half-taper fiber. Using the analytic formulas we calculated the TE and TM lasing modes and it is shown that the experimental results are in good agreement with the calculation prediction

InGaN multiple-quantum-well epifilms on GaN-sillicon substrates for microcavities and surface-emitting lasers

International Nuclear Information System (INIS)

Lee, June Key; Cho, Hoon; Kim, Bok Hee; Park, Si Hyun; Gu, Erdan; Watson, Ian; Dawson, Martin

2006-01-01

We report the processing of InGaN/GaN epifilms on GaN-silicon substrates. High-quality InGaN/GaN multi-quantum wells (MQWs) were grown on GaN-silicon substrates, and their membranes were successfully fabricated using a selective wet etching of silicon followed by a dry etching of the AlGaN buffer layer. With atomic force microscope (AFM) measurements and photoluminescence (PL) measurements, we investigated the physical and the optical properties of the InGaN/GaN MQWs membranes. On the InGaN/GaN MQW membranes, dielectric distributed Bragg reflector (DBRs) were successfully deposited, which give, new possibilities for use in GaN microcavity and surface-emitting laser fabrication.

Cavity-polariton interaction mediated by coherent acoustic phonons in semiconductor microcavities

DEFF Research Database (Denmark)

de Lima, Mauricio; Hey, Rudolf; Santos, Paul

The strong coupling between excitons in a quantum well (QW) and photons in a semiconductor microcavity leads to the formation of quasi-particles known as cavity-polaritons. In this contribution, we investigate their interaction with coherent acoustic phonons in the form of surface acoustic waves...

Continuous-wave optically pumped green perovskite vertical-cavity surface-emitter

KAUST Repository

Alias, Mohd Sharizal; Liu, Zhixiong; Alatawi, Abdullah; Ng, Tien Khee; Wu, Tao; Ooi, Boon S.

2017-01-01

We report an optically pumped green perovskite vertical-cavity surface-emitter operating in continuous-wave (CW) with a power density threshold of ~89 kW/cm2. The device has an active region of CH3NH3PbBr3 embedded in a dielectric microcavity

Multimode laser emission from dye-doped hollow polymer optical fibre

Indian Academy of Sciences (India)

2014-02-09

Feb 9, 2014 ... Fibre lasers; optical microcavities; whispering gallery modes. ... A blueshift in the mode structure was observed with decrease in fibre diameter leading to wide range tunability of the laser emission. ... International School of Photonics, Cochin University of Science & Technology, Cochin 682 022, India ...

Evidence of negative electrorefraction in type-II GaAs/GaAlAs short-period superlattice

International Nuclear Information System (INIS)

Shchukin, V A; Ledentsov, N N; Karachinsky, L Ya; Novikov, I I; Egorov, A Yu; Blokhin, S A; Maximov, M V; Gordeev, N Yu; Kulagina, M M; Ustinov, V M

2015-01-01

A type-II GaAs/GaAlAs short-period superlattice (SPSL) used as an electro-optic medium for the spectral range 820–850 nm is studied in a vertical microcavity geometry. SPSL is sandwiched between two GaAlAs distributed Bragg reflectors. Optical power reflectance (OR) spectra are measured as a function of applied reverse bias at different tilt angles and temperatures. All spectra reveal a blue shift of the reflectivity dip upon applied voltage which evidences a negative electrorefraction of the electro-optic medium. The shift enhances up to ∼0.6 nm once the exciton resonance is brought close to the wavelength of the reflectivity dip. As opposed to those modulators based on quantum–confined Stark effect, no increased absorption is observed at an applied bias, because the integrated intensity of the reflectivity dip in the OR spectra is virtually constant. This indicates a low absorption loss with applied bias and consequently a high potential for the increased dynamic range of the related modulator. (paper)

Optical confinement and light guiding in high dielectric contrast materials systems

Science.gov (United States)

Foresi, James S.

A study of silicon photonic devices, including waveguides and microcavities, is presented in this thesis. The high index difference of Silicon-On-Insulator materials is used to design submicron devices capable of light localization and routing. Losses due to interface roughness between the high and low index materials are measured to be 40dB/cm. An analysis of lithographically induced interface roughness is performed and a method for evaluating nanometer-scale roughness is presented. High index differences lead to compact bends and power splitters. Bends of 2.0μm radius are measured to have losses less than 0.5dB. Splitting angles of 5o with losses less than 1.5dB are demonstrated. The bends and splitters are the most compact devices of their kind. The design, fabrication and analysis of two light confining devices in the SOI system are presented: photonic band gap (PBG) and microdisk microcavities. A PBG waveguide microcavity with minimum dimensions of 0.10μm is fabricated and transmission measurements reveal cavity Q's of 265, a resonant wavelength of 1564nm, and a modal volume of 0.27/mu m3. This is the first demonstration of PBG resonance at optical frequencies. The PBG microcavity volume is two orders of magnitude smaller than has been achieved in other microcavity devices. Microdisk and microring resonators are demonstrated. A waveguide-coupled microring is shown to operate as a channel dropping filter with Q's of 250 and a free spectral range of 25nm. The application of the microcavity devices to spontaneous emission control of erbium-doped silicon is analyzed. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

Fabrication and characterization of microcavity lasers in rhodamine B doped SU8 using high energy proton beam

Science.gov (United States)

Venugopal Rao, S.; Bettiol, A. A.; Vishnubhatla, K. C.; Bhaktha, S. N. B.; Narayana Rao, D.; Watt, F.

2007-03-01

The authors present their results on the characterization of individual dye-doped microcavity polymer lasers fabricated using a high energy proton beam. The lasers were fabricated in rhodamine B doped SU8 resist with a single exposure step followed by chemical processing. The resulting trapezoidal shaped cavities had dimensions of ˜250×250μm2. Physical characterization of these structures was performed using a scanning electron microscope while the optical characterization was carried out by recording the emission subsequent to pumping the lasers with 532nm, 6 nanosecond pulses. The authors observed intense, narrow emission near 624nm with the best emission linewidth full width at half maximum of ˜9nm and a threshold ˜150μJ/mm2.

Finite-momentum condensation in a pumped microcavity

International Nuclear Information System (INIS)

Brierley, R. T.; Eastham, P. R.

2010-01-01

We calculate the absorption spectra of a semiconductor microcavity into which a nonequilibrium exciton population has been pumped. We predict strong peaks in the spectrum corresponding to collective modes analogous to the Cooper modes in superconductors and fermionic atomic gases. These modes can become unstable, leading to the formation of off-equilibrium quantum condensates. We calculate a phase diagram for condensation and show that the dominant instabilities can be at a finite momentum. Thus we predict the formation of inhomogeneous condensates, similar to Fulde-Ferrel-Larkin-Ovchinnikov states.

Microcavity polariton linewidths in the weak-disorder regime

DEFF Research Database (Denmark)

Borri, Paola; Langbein, Wolfgang Werner; Woggon, U.

2000-01-01

Polariton linewidths have been measured in a series of high-quality microcavities with different excitonic inhomogeneous broadening in the weak-disorder regime. We show experimentally that the influence of the disorder on the polariton linewidths is canceled when the polariton energies are far in...... in the tail of the excitonic absorption. The measured linewidths are quantitatively compared with an estimation using the measured excitonic absorption spectrum of the bare quantum wells, and good agreement is found....

An Instrument for Inspecting Aspheric Optical Surfaces and Components, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This is a Phase II SBIR proposal to develop an extremely versatile optical inspection tool for aspheric optical components and optics that are not easily inspected...

Optical properties of infrared FELs from the FELI Facility II

Energy Technology Data Exchange (ETDEWEB)

Saeki, K.; Okuma, S.; Oshita, E. [Free Electron Laser Institute, Osaka (Japan)] [and others

1995-12-31

The FELI Facility II has succeeded in infrared FEL oscillation at 1.91 {mu} m using a 68-MeV, 40-A electron beam from the FELI S-band linac in February 27, 1995. The FELI Facility II is composed of a 3-m vertical type undulator ({lambda}u=3.8cm, N=78, Km a x=1.4, gap length {ge}20mm) and a 6.72-m optical cavity. It can cover the wavelength range of 1-5{mu}m. The FELs can be delivered from the optical cavity to the diagnostics room through a 40-m evacuated optical pipeline. Wavelength and cavity length dependences of optical properties such as peak power, average power, spectrum width, FEL macropulse, FEL transverse profile are reported.

Microcavity-coupled fiber Bragg grating with tunable reflection spectra and speed of light.

Science.gov (United States)

Chen, Lei; Han, Ya; Liu, Qian; Liu, Yan-Ge; Zhang, Weigang; Chou, Keng C

2018-04-15

After a fiber Bragg grating (FBG) is fabricated, the reflection spectrum of the FBG is generally not tunable without mechanical deformation or temperature adjustment. Here we present a microcavity-coupled FBG with both a tunable reflection lineshape and dispersion using electromagnetically induced transparency. The Fano interference of light in the FBG and the microcavity allows for dramatic modification of the reflection spectrum. The phase of the reflected spectrum is continuously tunable between 0 and 2π to produce various Fano lineshapes. The dispersion of the output light is adjustable from normal dispersion to abnormal dispersion, consequently providing an adjustable speed of light. Additionally, it allows the FBG to switch from a notch filter to a bandpass filter at the resonant wavelength, which is not possible in a conventional uniform FBG.

Ultra-fast polariton dynamics in an organic microcavity

Directory of Open Access Journals (Sweden)

Polli D.

2013-03-01

Full Text Available We study an organic semiconductor microcavity operating in the strong-coupling regime using femtosecond pump-probe spectroscopy. By probing the photo-induced absorption bands, we characterize the time-dependent population densities of states in the two polariton branches. We found evidence of a scattering process from the upper-branch cavity polaritons to the exciton reservoir having a rate of (150 fs-1. A slower process similarly populates lower-branch polaritons with a rate of around (3ps-1

Laser-Machined Microcavities for Simultaneous Measurement of High-Temperature and High-Pressure

Directory of Open Access Journals (Sweden)

Zengling Ran

2014-08-01

Full Text Available Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure are demonstrated. These two cascaded microcavities are an air cavity and a composite cavity including a section of fiber and an air cavity. They are both placed into a pressure chamber inside a furnace to perform simultaneous pressure and high-temperature tests. The thermal and pressure coefficients of the short air cavity are ~0.0779 nm/°C and ~1.14 nm/MPa, respectively. The thermal and pressure coefficients of the composite cavity are ~32.3 nm/°C and ~24.4 nm/MPa, respectively. The sensor could be used to separate temperature and pressure due to their different thermal and pressure coefficients. The excellent feature of such a sensor head is that it can withstand high temperatures of up to 400 °C and achieve precise measurement of high-pressure under high temperature conditions.

Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure.

Science.gov (United States)

Ran, Zengling; Liu, Shan; Liu, Qin; Huang, Ya; Bao, Haihong; Wang, Yanjun; Luo, Shucheng; Yang, Huiqin; Rao, Yunjiang

2014-08-07

Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure are demonstrated. These two cascaded microcavities are an air cavity and a composite cavity including a section of fiber and an air cavity. They are both placed into a pressure chamber inside a furnace to perform simultaneous pressure and high-temperature tests. The thermal and pressure coefficients of the short air cavity are ~0.0779 nm/°C and ~1.14 nm/MPa, respectively. The thermal and pressure coefficients of the composite cavity are ~32.3 nm/°C and ~24.4 nm/MPa, respectively. The sensor could be used to separate temperature and pressure due to their different thermal and pressure coefficients. The excellent feature of such a sensor head is that it can withstand high temperatures of up to 400 °C and achieve precise measurement of high-pressure under high temperature conditions.

Electrically Injected Polariton Lasing from a GaAs-Based Microcavity under Magnetic Field

KAUST Repository

Bhattacharya, Pallab; Das, Ayan; Jankowski, Marc; Bhowmick, Sishir; Lee, Chi-Sen; Jahangir, Shafat

2012-01-01

Suppression of relaxation bottleneck and subsequent polariton lasing is observed in a GaAs-based microcavity under the application of a magnetic field. The threshold injection current density is 0.32 A/cm2 at 7 Tesla.

Non-Hermitian optics in atomic systems

Science.gov (United States)

Zhang, Zhaoyang; Ma, Danmeng; Sheng, Jiteng; Zhang, Yiqi; Zhang, Yanpeng; Xiao, Min

2018-04-01

A wide class of non-Hermitian Hamiltonians can possess entirely real eigenvalues when they have parity-time (PT) symmetric potentials. Recently, this family of non-Hermitian systems has attracted considerable attention in diverse areas of physics due to their extraordinary properties, especially in optical systems based on solid-state materials, such as coupled gain-loss waveguides and microcavities. Considering the desired refractive index can be effectively manipulated through atomic coherence, it is important to realize such non-Hermitian optical potentials and further investigate their distinct properties in atomic systems. In this paper, we review the recent theoretical and experimental progress of non-Hermitian optics with coherently prepared multi-level atomic configurations. The realizations of (anti-) PT symmetry with different schemes have extensively demonstrated the special optical properties of non-Hermitian optical systems with atomic coherence.

Higher-order photon bunching in a semiconductor microcavity

DEFF Research Database (Denmark)

Assmann, M.; Veit, F.; Bayer, M.

2009-01-01

Quantum mechanically indistinguishable particles such as photons may show collective behavior. Therefore, an appropriate description of a light field must consider the properties of an assembly of photons instead of independent particles. We have studied multiphoton correlations up to fourth order...... in the single-mode emission of a semiconductor microcavity in the weak and strong coupling regimes. The counting statistics of single photons were recorded with picosecond time resolution, allowing quantitative measurement of the few-photon bunching inside light pulses. Our results show bunching behavior...

Magnetic-field induced bistability in a quasi-one-dimensional semiconductor microcavity

International Nuclear Information System (INIS)

Zhang, Chuanyi; Zhang, Weifeng

2015-01-01

We theoretically study the magnetic-field induced bistability in a quasi-one-dimensional semiconductor microcavity. A critical magnetic field is obtained, and the bistability appears if a magnetic field is greater than the critical value. For a positive energy detuning of the pump from the bare exciton polaritons, one bistability loop first emerges, then it divides into two loops, and finally one of them vanishes with the increasing magnetic field. This phenomenon originates from the magnetic-field modulated interactions for opposite spins. In the variational process, there are two important effects: one is a logic gate with a small variation of the excitation laser, and the other is a spin texture like skyrmion and this texture is periodic if the energy detuning varies periodically in real space, which is useful for designing the spin-dependent optoelectronic devices. - Highlights: • We study the bistability induced by a magnetic field in a microcavity. • One bistability loop can divide into two, and then the two loops return to one. • A spin texture like skyrmion and logic gate arise in the variation of bistability loop

SERS-active ZnO/Ag hybrid WGM microcavity for ultrasensitive dopamine detection

Science.gov (United States)

Lu, Junfeng; Xu, Chunxiang; Nan, Haiyan; Zhu, Qiuxiang; Qin, Feifei; Manohari, A. Gowri; Wei, Ming; Zhu, Zhu; Shi, Zengliang; Ni, Zhenhua

2016-08-01

Dopamine (DA) is a potential neuro modulator in the brain which influences a variety of motivated behaviors and plays a key role in life science. A hybrid ZnO/Ag microcavity based on Whispering Gallery Mode (WGM) effect has been developed for ultrasensitive detection of dopamine. Utilizing this effect of structural cavity mode, a Raman signal of R6G (5 × 10-3 M) detected by this designed surface-enhanced Raman spectroscopy (SERS)-active substrate was enhanced more than 10-fold compared with that of ZnO film/Ag substrate. Also, this hybrid microcavity substrate manifests high SERS sensitivity to rhodamine 6 G and detection limit as low as 10-12 M to DA. The Localized Surface Plasmons of Ag nanoparticles and WGM-enhanced light-matter interaction mainly contribute to the high SERS sensitivity and help to achieve a lower detection limit. This designed SERS-active substrate based on the WGM effect has the potential for detecting neurotransmitters in life science.

Enhanced photoconductivity and fine response tuning in nanostructured porous silicon microcavities

Energy Technology Data Exchange (ETDEWEB)

Urteaga, R; MarIn, O; Acquaroli, L N; Schmidt, J A; Koropecki, R R [INTEC-UNL-CONICET, Guemes 3450 - 3000 Santa Fe (Argentina); Comedi, D, E-mail: rkoro@intec.ceride.gov.a [CONICET y LAFISO, Departamento de Fisica, FACET, Universidad Nacional de Tucuman (Argentina)

2009-05-01

We used light confinement in optical microcavities to achieve a strong enhancement and a precise wavelength tunability of the electrical photoconductance of nanostructured porous silicon (PS). The devices consist of a periodic array of alternating PS layers, electrochemically etched to have high and low porosities - and therefore distinct dielectric functions. A central layer having a doubled thickness breaks up the symmetry of the one-dimensional photonic structure, producing a resonance in the photonic band gap that is clearly observed in the reflectance spectrum. The devices were transferred to a glass coated with a transparent SnO{sub 2} electrode, while an Al contact was evaporated on its back side. The electrical conductance was measured as a function of the photon energy. A strong enhancement of the conductance is obtained in a narrow (17nm FWHM) band peaking at the resonance. We present experimental results of the angular dependence of this photoconductance peak energy, and propose an explanation of the conductivity behaviour supported by calculations of the internal electromagnetic field. These devices are promising candidates for finely tuned photoresistors with potential application as chemical sensors and biosensors.

Seeding Dynamics of Nonlinear Polariton Emission from a Microcavity

DEFF Research Database (Denmark)

Østergaard, John Erland; Langbein, Wolfgang Werner; Jensen, Jacob Riis

2000-01-01

Summary form only given. The dynamics of polaritons in microcavity samples is presently under intense debate, in particular whether or not the so-called Boser action is possible. In this work, we investigate a λ cavity with a homogeneously broadened 25 nm GaAs quantum well at the antinode...... at a temperature of 10 K. We can thus inject well-defined polariton populations in k-space revealing how different initial and final state populations may influence the dynamics....

Photoluminescence eigenmodes in the ZnO semiconductor microcavity on the Ag/Si substrate

Czech Academy of Sciences Publication Activity Database

Luo, X.; Wang, J.; Mao, H.; Remeš, Zdeněk; Král, Karel

2013-01-01

Roč. 112, č. 4 (2013), s. 821-825 ISSN 0947-8396 R&D Projects: GA MŠk LH12186 Institutional support: RVO:68378271 Keywords : ZnO * photoluminescence * microcavity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.694, year: 2013

Substantial enhancement of red emission intensity by embedding Eu-doped GaN into a microcavity

Directory of Open Access Journals (Sweden)

Tomohiro Inaba

2016-04-01

Full Text Available We investigate resonantly excited photoluminescence from a Eu,O-codoped GaN layer embedded into a microcavity, consisting of an AlGaN/GaN distributed Bragg reflector and a Ag reflecting mirror. The microcavity is responsible for a 18.6-fold increase of the Eu emission intensity at ∼10K, and a 21-fold increase at room temperature. We systematically investigate the origin of this enhancement, and we conclude that it is due to the combination of several effects including, the lifetime shortening of the Eu emission, the strain-induced piezoelectric effect, and the increased extraction and excitation field efficiencies. This study paves the way for an alternative method to enhance the photoluminescence intensity in rare-earth doped semiconductor structures.

High-Speed Semiconductor Vertical-Cavity Surface-Emitting Lasers for Optical Data-Transmission Systems (Review)

Science.gov (United States)

Blokhin, S. A.; Maleev, N. A.; Bobrov, M. A.; Kuzmenkov, A. G.; Sakharov, A. V.; Ustinov, V. M.

2018-01-01

The main problems of providing a high-speed operation semiconductor lasers with a vertical microcavity (so-called "vertical-cavity surface-emitting lasers") under amplitude modulation and ways to solve them have been considered. The influence of the internal properties of the radiating active region and the electrical parasitic elements of the equivalent circuit of lasers are discussed. An overview of approaches that lead to an increase of the cutoff parasitic frequency, an increase of the differential gain of the active region, the possibility of the management of mode emission composition and the lifetime of photons in the optical microcavities, and reduction of the influence of thermal effects have been presented. The achieved level of modulation bandwidth of ˜30 GHz is close to the maximum achievable for the classical scheme of the direct-current modulation, which makes it necessary to use a multilevel modulation format to further increase the information capacity of optical channels constructed on the basis of vertical-cavity surface-emitting lasers.

Optimization of three-dimensional micropost microcavities for cavity quantum electrodynamics

International Nuclear Information System (INIS)

Vuckovic, Jelena; Pelton, Matthew; Scherer, Axel; Yamamoto, Yoshihisa

2002-01-01

This paper presents a detailed analysis, based on the first-principles finite-difference time-domain method, of the resonant frequency, quality factor (Q), mode volume (V), and radiation pattern of the fundamental (HE 11 ) mode in a three-dimensional distributed-Bragg-reflector (DBR) micropost microcavity. By treating this structure as a one-dimensional cylindrical photonic crystal containing a single defect, we are able to push the limits of Q/V beyond those achievable by standard micropost designs, based on the simple rules established for planar DBR microcavities. We show that some of the rules that work well for designing large-diameter microposts (e.g., high-refractive-index contrast) fail to provide high-quality cavities with small diameters. By tuning the thicknesses of mirror layers and the spacer, the number of mirror pairs, the refractive indices of high- and low-refractive index regions, and the cavity diameter, we are able to achieve Q as high as 10 4 , together with a mode volume of 1.6 cubic wavelengths of light in the high-refractive-index material. The combination of high Q and small V makes these structures promising candidates for the observation of such cavity-quantum-electrodynamics phenomena as strong coupling between a quantum dot and the cavity field, and single-quantum-dot lasing

Monitoring of benzene-induced hematotoxicity in mice by serial leukocyte counting using a microcavity array.

Science.gov (United States)

Hosokawa, Masahito; Asami, Marie; Yoshino, Tomoko; Tsujimura, Noriyuki; Takahashi, Masayuki; Nakasono, Satoshi; Tanaka, Tsuyoshi; Matsunaga, Tadashi

2013-02-15

Monitoring of hematotoxicity, which requires serial blood collection, is difficult to carry out in small animals due to a lack of non-invasive, individual animal-appropriate techniques that enable enumeration of leukocyte subsets from limited amounts of whole blood. In this study, a microfluidic device equipped with a microcavity array that enables highly efficient separation of leukocytes from submicroliters of whole blood was applied for hematotoxicity monitoring in mice. The microcavity array can specifically separate leukocytes from whole blood based on differences in the size and deformability between leukocytes and other blood cells. Mouse leukocytes recovered on aligned microcavities were continuously processed for image-based immunophenotypic analysis. Our device successfully recovered almost 100% of mouse leukocytes in 0.1 μL of whole blood without the effect of serial blood collection such as changes in body weight and total leukocyte count. We assessed benzene-associated hematotoxicity in mice using this system. Mice were administered with benzene once daily and the depression of leukocyte numbers induced in individual mice was successfully monitored from tail vein blood collected every other day for 2 weeks. Serial monitoring of the leukocyte number in individual mice will contribute to the understanding of hematotoxicity and reduction of the number of animal experiment trials. Copyright © 2012 Elsevier B.V. All rights reserved.

Quantum condensation from a tailored exciton population in a microcavity

International Nuclear Information System (INIS)

Eastham, P. R.; Phillips, R. T.

2009-01-01

An experiment is proposed on the coherent quantum dynamics of a semiconductor microcavity containing quantum dots. Modeling the experiment using a generalized Dicke model, we show that a tailored excitation pulse can create an energy-dependent population of excitons, which subsequently evolves to a quantum condensate of excitons and photons. The population is created by a generalization of adiabatic rapid passage and then condenses due to a dynamical analog of the BCS instability.

Monolithic, High-Speed Fiber-Optic Switching Array for Lidar, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This NASA SBIR Phase II effort will develop a 1 x 10 prototype non-mechanical fiber optic switch for use with high power lasers. The proposed optical device is a...

Multi-Valued Spin Switch in a Semiconductor Microcavity

Science.gov (United States)

Paraïso, T. K.; Wouters, M.; Léger, Y.; Morier-Genoud, F.; Deveaudhyphen; Plédran, B.

2011-12-01

In this work, we report on the first realization of multi-valued spin switching in the solid-state. We investigate the physics of spinor bistability with microcavity polaritons in a trap. Spinor interactions lead to special bistability regimes with decoupled thresholds for spin-up and spin-down polaritons. This allows us to establish state-of-the-art spin switching operations. We evidence polarization hysteresis and determine appropriate conditions to achieve spin multistability. For a given excitation condition, three stable spin states coexist for the system. These results open new pathways for the development of innovative spin-based logic gates and memory devices.

Microcavity quantum-dot systems for non-equilibrium Bose-Einstein condensation

International Nuclear Information System (INIS)

Piper, I M; Ediger, M; Wilson, A M; Wu, Y; Phillips, R T; Eastham, P R; Hugues, M; Hopkinson, M

2010-01-01

We review the practical conditions required to achieve a non-equilibrium BEC driven by quantum dynamics in a system comprising a microcavity field mode and a distribution of localised two-level systems driven to a step-like population inversion profile. A candidate system based on eight 3.8nm layers of In 0.23 Ga 0.77 As in GaAs shows promising characteristics with regard to the total dipole strength which can be coupled to the field mode.

Optical system for laser triggering of PBFA II

International Nuclear Information System (INIS)

Hamil, R.A.; Seamons, L.O.; Schanwald, L.P.; Gerber, R.A.

1985-01-01

The PBFA II laser triggering optical system consists of nearly 300 optical components. These optics must be sufficiently precise to preserve the laser beam quality, as well as to equally distribute the energy of the UV laser beam to the 36, 5.5 MV gas-filled switches at precisely the same instant. Both index variation and cleanliness of the air long the laser path must be controlled. The manual alignment system is capable of alignment to better than the acceptable error of 200 microradians (laser to switches). A technique has been devised to ease the alignment procedure by using a special high gain video camera and a tool alignment telescope to view retroreflective tape targets having optical brightness gains over white surfaces of 10/sup 3/. The camera is a charge-coupled detector intensified by a double microchannel plate having an optical gain of between 10/sup 4/ and 10/sup 5/

Reciprocal-Space Engineering of Quasi-Bound States in the Continuum in Photonic Crystal Slabs for High-Q Microcavities

DEFF Research Database (Denmark)

Chung, Il-Sug; Taghizadeh, Alireza

2017-01-01

The bound states in the continuum (BICs) in photonic crystal (PhC) slabs presume infinite periodicity in the inplane direction. Thus, a large number of unit cells are typically required to implement the BICs with a high quality (Q) factor. Here, we report on a method to engineer the reciprocal......-space properties of BICs, which enables to keep the effect of the BIC phenomenon strong even for a microcavity of a few unit cells. For example, based on this method, a 3D microcavity of 4 unit cells can attain a Q factor of 18k. This allows for various BIC studies in a very compact platform, as well as novel...

Utilizing an open-microcavity optoacoustic sensor for spectroscopic determination of methemoglobin concentration

Science.gov (United States)

Peterson, Ralph W.; Kadugodinandareddy, Kavya; Karunakaran, Vinitha; Whitney, Casey; Ling, Jian; Ye, Jing Yong

2015-03-01

We present a simple, non-destructive photoacoustic spectroscopy method utilizing a unique open-microcavity optoacoustic sensor to measure the concentration ratio of Methemoglobin (MetHb) in an optically scattering medium. Elevated levels of MetHb, present for example in the blood disorder Methemeglobinemia, cannot be detected by conventional pulse oximetry, and may result in inaccurate arterial oxygen saturation measurements. Samples with different ratios of Oxygenated Hemoglobin (HbO2), Deoxygenated Hemoglobin (HHb), and MetHb were obtained and mixed with nanoscale latex beads to present an optical scattering effect. Polymer encapsulated hemoglobin (PEH) samples were also studied. A sample chamber containing 20 μL of each sample was positioned directly underneath our patented optoacoustic sensor. Unlike a piezoelectric transducer, our optoacoustic sensor allows an excitation laser beam from an OPO laser to pass through and be absorbed by the sample to produce a photoacoustic signal. The cavity layer of the optoacoustic sensor is exposed directly to the resulting ultrasound signal, which causes an intensity modulation of a HeNe laser that is used to monitor the resonance condition of the sensor. A probe laser beam is total internally reflected off of the sensor and detected with a fiber-coupled APD detector. Three wavelengths are chosen for our excitation laser based on the absorption peaks and isobestic points of HHb, HbO2, and MetHb. Using established values of the molar extinction coefficients of HbO2, HHb, and MetHb a set of three simultaneous equations can be solved to accurately determine the concentration ratio of MetHb.

Microcavity quantum-dot systems for non-equilibrium Bose-Einstein condensation

Energy Technology Data Exchange (ETDEWEB)

Piper, I M; Ediger, M; Wilson, A M; Wu, Y; Phillips, R T [Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Eastham, P R [School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Hugues, M; Hopkinson, M, E-mail: imp24@cam.ac.u [Department of Electronic and Electrical Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom)

2010-09-01

We review the practical conditions required to achieve a non-equilibrium BEC driven by quantum dynamics in a system comprising a microcavity field mode and a distribution of localised two-level systems driven to a step-like population inversion profile. A candidate system based on eight 3.8nm layers of In{sub 0.23}Ga{sub 0.77}As in GaAs shows promising characteristics with regard to the total dipole strength which can be coupled to the field mode.

77 FR 36579 - II-VI, Inc., Infrared Optics-Saxonburg Division, Saxonburg, PA; Leased Workers From Adecco, Carol...

Science.gov (United States)

2012-06-19

...., Infrared Optics-Saxonburg Division, Saxonburg, PA; Leased Workers From Adecco, Carol Harris, Unlimited Staffing, and Staffmark, Working On-Site at II-VI, Inc., Infrared Optics-Saxonburg Division, Saxonburg, PA... workers and former workers of II-VI, Inc., Infrared Optics-Saxonburg Division, Saxonburg, Pennsylvania...

Quantum computers based on electron spins controlled by ultrafast off-resonant single optical pulses.

Science.gov (United States)

Clark, Susan M; Fu, Kai-Mei C; Ladd, Thaddeus D; Yamamoto, Yoshihisa

2007-07-27

We describe a fast quantum computer based on optically controlled electron spins in charged quantum dots that are coupled to microcavities. This scheme uses broadband optical pulses to rotate electron spins and provide the clock signal to the system. Nonlocal two-qubit gates are performed by phase shifts induced by electron spins on laser pulses propagating along a shared waveguide. Numerical simulations of this scheme demonstrate high-fidelity single-qubit and two-qubit gates with operation times comparable to the inverse Zeeman frequency.

Numerical study on discharge process of microcavity plasma

International Nuclear Information System (INIS)

Xia Guangqing; Xue Weihua; Wang Dongxue; Zhu Guoqiang; Zhu Yu

2012-01-01

The evolution of plasma parameters during high pressure discharge in the microcavity with a hollow anode was numerically studied, with a two-dimensional self-consistent fluid model. The simulations were performed with argon at 13.3 kPa. The numerical results show that during the discharge the electric field around the cathode transforms from an axial field to a radial field, the plasma density gets the maximum value on the central line of the cavity and the location of the maximum density moves from the region near anode at the initial stage to the cathode vicinity at the stable stage, and the maximum electron temperature occurs in the ring sheath of cathode. (authors)

Electrical investigations of hybrid OLED microcavity structures with novel encapsulation methods

Science.gov (United States)

Meister, Stefan; Brückner, Robert; Fröb, Hartmut; Leo, Karl

2016-04-01

An electrical driven organic solid state laser is a very challenging goal which is so far well beyond reach. As a step towards realization, we monolithically implemented an Organic Light Emitting Diode (OLED) into a dielectric, high quality microcavity (MC) consisting of two Distributed Bragg Reectors (DBR). In order to account for an optimal optical operation, the OLED structure has to be adapted. Furthermore, we aim to excite the device not only electrically but optically as well. Different OLED structures with an emission layer consisting of Alq3:DCM (2 wt%) were investigated. The External Quantum Efficiencies (EQE) of this hybrid structures are in the range of 1-2 %, as expected for this material combination. Including metal layers into a MC is complicated and has a huge impact on the device performance. Using Transfer-Matrix-Algorithm (TMA) simulations, the best positions for the metal electrodes are determined. First, the electroluminescence (EL) of the adjusted OLED structure on top of a DBR is measured under nitrogen atmosphere. The modes showed quality factors of Q = 60. After the deposition of the top DBR, the EL is measured again and the quality factors increased up to Q = 600. Considering the two 25-nm-thick-silver contacts a Q-factor of 600 is very high. The realization of a suitable encapsulation method is important. Two approaches were successfully tested. The first method is based on the substitution of a DBR layer with a layer produced via Atomic Layer Deposition (ALD). The second method uses a 0.15-mm-thick cover glass glued on top of the DBR with a 0.23-μm-thick single-component glue layer. Due to the working encapsulation, it is possible to investigate the sample under ambient conditions.

Ultralow loss, high Q, four port resonant couplers for quantum optics and photonics.

Science.gov (United States)

Rokhsari, H; Vahala, K J

2004-06-25

We demonstrate a low-loss, optical four port resonant coupler (add-drop geometry), using ultrahigh Q (>10(8)) toroidal microcavities. Different regimes of operation are investigated by variation of coupling between resonator and fiber taper waveguides. As a result, waveguide-to-waveguide power transfer efficiency of 93% (0.3 dB loss) and nonresonant insertion loss of 0.02% (photonic networks.

The Optical Design of the PEP-II Injection Beamlines

CERN Document Server

Fieguth, T

1996-01-01

The optical design of the PEP-II electron and positron Injection Beamlines is described. Use of the existing high power, low emittance beams available from the SLC damping rings require that pulsed extraction of 9.0 GeV electrons and 3.1 GeV positrons for injection into the PEP-II rings occur in the early sectors of the accelerator. More than 5 kilometers of new beam transport lines have been designed and are being constructed to bring these beams to their respective rings. The optical design maximizes the tolerance to errors especially to those contributing to beam size and position jitter. Secondly, the design minimizes costs by utilizing existing components or component designs and minimizing the number required. Here we discuss important attributes including choice of lattice, specification of error tolerances, including errors in construction, alignment, field errors, power supply stability, and orbit correction.

The Optical Design of the PEP-II Injection Beamlines

Energy Technology Data Exchange (ETDEWEB)

Fieguth, Ted

2003-05-23

The optical design of the PEP-II electron and positron Injection Beamlines is described. Use of the existing high power, low emittance beams available from the SLC damping rings require that pulsed extraction of 9.0 GeV electrons and 3.1 GeV positrons for injection into the PEP-II rings occur in the early sectors of the accelerator. More than 5 kilometers of new beam transport lines have been designed and are being constructed to bring these beams to their respective rings. The optical design maximizes the tolerance to errors especially to those contributing to beam size and position jitter. Secondly, the design minimizes costs by utilizing existing components or component designs and minimizing the number required. Here we discuss important attributes including choice of lattice, specification of error tolerances, including errors in construction, alignment, field errors, power supply stability, and orbit correction.

Two-photon interference from a quantum dot-microcavity: Persistent pure-dephasing and suppression of time-jitter

DEFF Research Database (Denmark)

Unsleber, Sebastian; McCutcheon, Dara; Dambach, Michael

2015-01-01

We demonstrate the emission of highly indistinguishable photons from a quasi-resonantly pumped coupledquantum dot–microcavity system operating in the regime of cavity quantum electrodynamics. Changing thesample temperature allows us to vary the quantum dot–cavity detuning and, on spectral resonance...

Two-photon interference from a quantum dot-microcavity: Persistent pure-dephasing and suppression of time-jitter

DEFF Research Database (Denmark)

Unsleber, S.; McCutcheon, Dara; Dambach, M.

We demonstrate the emission of highly indistinguishable photons from a quasiresonantly pumped coupled quantum dot–microcavity system operating in the regime of cavity quantum electrodynamics. Changing the sample temperature allows us to vary the quantum dot–cavity detuning, and on spectral...

Modelling Laser Milling of Microcavities for the Manufacturing of DES with Ensembles

Directory of Open Access Journals (Sweden)

Pedro Santos

2014-01-01

Full Text Available A set of designed experiments, involving the use of a pulsed Nd:YAG laser system milling 316L Stainless Steel, serve to study the laser-milling process of microcavities in the manufacture of drug-eluting stents (DES. Diameter, depth, and volume error are considered to be optimized as functions of the process parameters, which include laser intensity, pulse frequency, and scanning speed. Two different DES shapes are studied that combine semispheres and cylinders. Process inputs and outputs are defined by considering the process parameters that can be changed under industrial conditions and the industrial requirements of this manufacturing process. In total, 162 different conditions are tested in a process that is modeled with the following state-of-the-art data-mining regression techniques: Support Vector Regression, Ensembles, Artificial Neural Networks, Linear Regression, and Nearest Neighbor Regression. Ensemble regression emerged as the most suitable technique for studying this industrial problem. Specifically, Iterated Bagging ensembles with unpruned model trees outperformed the other methods in the tests. This method can predict the geometrical dimensions of the machined microcavities with relative errors related to the main average value in the range of 3 to 23%, which are considered very accurate predictions, in view of the characteristics of this innovative industrial task.

77 FR 27081 - II-VI, Incorporated, Infrared Optics-Saxonburg Division, Saxonburg, Pennsylvania; Notice of...

Science.gov (United States)

2012-05-08

..., Infrared Optics--Saxonburg Division, Saxonburg, Pennsylvania; Notice of Affirmative Determination Regarding... Assistance (TAA) applicable to workers and former workers of II-VI, Incorporated, Infrared Optics--Saxonburg...). The workers were engaged in employment related to the production of infrared and CO 2 laser optics...

Design and Optimization of Dual Optical Fiber MEMS Pressure Sensor For Biomedical Applications

International Nuclear Information System (INIS)

Dagang, Guo; Po, Samuel Ng Choon; Hock, Francis Tay Eng; Rongming, Lin

2006-01-01

A novel Single Deeply Corrugated Diaphragm (SDCD) based dual optical fiber Fabry-Perot pressure sensor for blood pressure measurement is proposed. Both mechanical and optical simulations are performed to demonstrate the feasibility and superior performance of the proposed sensor. Result shows that less than 2% nonlinearity can be achieved for the proposed sensor using optimal Fabry-Perot microcavity. Also, the fabrication process of the proposed sensor is given, instead of complicated fusion bonding process, only bulk and surface micromachining techniques are required which facilitate the mass production of such biocompatible and disposable pressure sensors

High-Q/V Monolithic Diamond Microdisks Fabricated with Quasi-isotropic Etching.

Science.gov (United States)

Khanaliloo, Behzad; Mitchell, Matthew; Hryciw, Aaron C; Barclay, Paul E

2015-08-12

Optical microcavities enhance light-matter interactions and are essential for many experiments in solid state quantum optics, optomechanics, and nonlinear optics. Single crystal diamond microcavities are particularly sought after for applications involving diamond quantum emitters, such as nitrogen vacancy centers, and for experiments that benefit from diamond's excellent optical and mechanical properties. Light-matter coupling rates in experiments involving microcavities typically scale with Q/V, where Q and V are the microcavity quality-factor and mode-volume, respectively. Here we demonstrate that microdisk whispering gallery mode cavities with high Q/V can be fabricated directly from bulk single crystal diamond. By using a quasi-isotropic oxygen plasma to etch along diamond crystal planes and undercut passivated diamond structures, we create monolithic diamond microdisks. Fiber taper based measurements show that these devices support TE- and TM-like optical modes with Q > 1.1 × 10(5) and V < 11(λ/n) (3) at a wavelength of 1.5 μm.

Scarred resonances and steady probability distribution in a chaotic microcavity

International Nuclear Information System (INIS)

Lee, Soo-Young; Rim, Sunghwan; Kim, Chil-Min; Ryu, Jung-Wan; Kwon, Tae-Yoon

2005-01-01

We investigate scarred resonances of a stadium-shaped chaotic microcavity. It is shown that two components with different chirality of the scarring pattern are slightly rotated in opposite ways from the underlying unstable periodic orbit, when the incident angles of the scarring pattern are close to the critical angle for total internal reflection. In addition, the correspondence of emission pattern with the scarring pattern disappears when the incident angles are much larger than the critical angle. The steady probability distribution gives a consistent explanation about these interesting phenomena and makes it possible to expect the emission pattern in the latter case

Polariton solitons and nonlinear localized states in a one-dimensional semiconductor microcavity

Science.gov (United States)

Chen, Ting-Wei; Cheng, Szu-Cheng

2018-01-01

This paper presents numerical studies of cavity polariton solitons (CPSs) in a resonantly pumped semiconductor microcavity with an imbedded spatial defect. In the bistable regime of the well-known homogeneous polariton condensate, with proper incident wave vector and pump strength, bright and/or dark cavity solitons can be found in the presence of a spatially confined potential. The minimum pump strength required to observe the CPSs or nonlinear localized states in this parametric pump scheme is therefore reported.

Detection of protein kinases P38 based on reflectance spectroscopy with n-type porous silicon microcavities for diagnosing hydatidosis hydatid disease

Science.gov (United States)

Lv, Xiaoyi; Lv, Guodong; Jia, Zhenhong; Wang, Jiajia; Mo, Jiaqing

2014-11-01

Detection of protein kinases P38 of Echinococcus granulosus and its homologous antibody have great value for early diagnosis and treatment of hydatidosis hydatid disease. In this experiment, n-type mesoporous silicon microcavities have been successfully fabricated without KOH etching or oxidants treatment that reported in other literature. We observed the changes of the reflectivity spectrum before and after the antigen-antibody reaction by n-type mesoporous silicon microcavities. The binding of protein kinases P38 and its homologous antibody causes red shifts in the reflection spectrum of the sensor, and the red shift was proportional to the protein kinases P38 concentration with linear relationship.

Porphyrin-functionalized porous polysulfone membrane towards an optical sensor membrane for sorption and detection of cadmium(II)

Energy Technology Data Exchange (ETDEWEB)

Zhao, Lizhi, E-mail: zhaolizhi_phd@163.com [State Key Laboratory of Separation Membranes and Membrane Processes, School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Li, Min; Liu, Manman; Zhang, Yuecong [State Key Laboratory of Separation Membranes and Membrane Processes, School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Wu, Chenglin [School of Pharmaceutical and Chemical Engineering, Taizhou University, Taizhou 317000, Zhejiang Province (China); Zhang, Yuzhong, E-mail: zhangyz2004cn@163.com [State Key Laboratory of Separation Membranes and Membrane Processes, School of Materials Science and Engineering, Tianjin Polytechnic University, Tianjin 300387 (China)

2016-01-15

Highlights: • An optical sensor membrane is prepared by TMPyP and PNaSS-grafted PSF membrane. • The optical sensor membrane shows enhanced sorption for cadmium(II). • Visual and spectrophotometric detection can be achieved. • The functional membrane exhibits good stability and reusability. - Abstract: In this study, an optical sensor membrane was prepared for sorption and detection of cadmium(II) (Cd(II)) in aqueous solution. A polyanion, poly(sodium 4-styrenesulfonate) (PNaSS), was grafted onto the chloromethylated polysulfone (CMPSF) microporous membrane via surface-initiated ATRP. 5,10,15,20-tetrakis(4-N-methylpyridyl) porphyrin p-toluenesulfonate (TMPyP) was immobilized onto the PNaSS-grafted polysulfone (PSF-PNaSS) membrane through electrostatic interaction. The TMPyP-functionalized membrane exhibited an enhanced sorption for, and distinct color and spectral response to cadmium(II) (Cd(II)) in aqueous solution. Larger immobilization capacity of TMPyP on the membrane led to stronger sorption for Cd(II), and smaller one made the optical sensor have a faster (in minutes) and more sensitive response to the ion. The detection limit study indicated that the functional membrane with proper amount of TMPyP (<0.5 mg/g) could still have color and spectral response to Cd(II) solutions at an extreme low concentration (10{sup −4} mg/L). The optical sensor membrane exhibited good stability and reusability which made it efficient for various sorptive removal and detection applications.

Polarization-dependent solitons in the strong coupling regime of semiconductor microcavities

International Nuclear Information System (INIS)

Fu, Y.; Zhang, W.L.; Wu, X.M.

2015-01-01

This paper studies the influence of polarization on formation of vectorial polariton soliton in semiconductor microcavities through numerical simulations. It is found that the polariton solution greatly depends on the polarization of both the pump and exciting fields. By properly choosing the pump and exciting field polarization, bright–bright or bright–dark vectorial polariton solitons can be formed. Especially, when the input conditions of pump or exciting field of the two opposite polarizations are slightly asymmetric, an interesting phenomenon that the dark solitons transform into bright solitons occurs in the branch of soliton solutions.

77 FR 21586 - II-VI, Incorporated, Infrared Optics-Saxonburg Division, Saxonburg, PA; Notice of Affirmative...

Science.gov (United States)

2012-04-10

..., Infrared Optics--Saxonburg Division, Saxonburg, PA; Notice of Affirmative Determination Regarding... Assistance (TAA) applicable to workers and former workers of II-VI, Incorporated, Infrared Optics--Saxonburg...). The workers were engaged in employment related to the production of infrared and CO 2 laser optics...

Laser startup optics for Baseball II and future mirror machines

International Nuclear Information System (INIS)

Frank, A.M.; Chargin, A.K.; Brown, N.J.

1975-01-01

The laser startup system for Baseball II-T uses a 300-J CO 2 laser to hit a 100-μ diameter pellet with a laser power density on the order of 10 13 W/cm 2 . The laser is a 20-cm diameter unstable resonator transversely excited (TEA) oscillator. The beam is split and then focused using off-axis parabolas. The symmetric configuration and central obscuration of the CO 2 beam allow coaxial alignment and pellet detection optics. This experiment primarily uses commercially available systems and components. Optical elements were fabricated both by direct machining and standard polishing techniques. The laser and optical systems are directly scalable to reactor requirements using demonstrated technologies

Micro-combs: A novel generation of optical sources

Science.gov (United States)

Pasquazi, Alessia; Peccianti, Marco; Razzari, Luca; Moss, David J.; Coen, Stéphane; Erkintalo, Miro; Chembo, Yanne K.; Hansson, Tobias; Wabnitz, Stefan; Del'Haye, Pascal; Xue, Xiaoxiao; Weiner, Andrew M.; Morandotti, Roberto

2018-01-01

The quest towards the integration of ultra-fast, high-precision optical clocks is reflected in the large number of high-impact papers on the topic published in the last few years. This interest has been catalysed by the impact that high-precision optical frequency combs (OFCs) have had on metrology and spectroscopy in the last decade [1-5]. OFCs are often referred to as optical rulers: their spectra consist of a precise sequence of discrete and equally-spaced spectral lines that represent precise marks in frequency. Their importance was recognised worldwide with the 2005 Nobel Prize being awarded to T.W. Hänsch and J. Hall for their breakthrough in OFC science [5]. They demonstrated that a coherent OFC source with a large spectrum - covering at least one octave - can be stabilised with a self-referenced approach, where the frequency and the phase do not vary and are completely determined by the source physical parameters. These fully stabilised OFCs solved the challenge of directly measuring optical frequencies and are now exploited as the most accurate time references available, ready to replace the current standard for time. Very recent advancements in the fabrication technology of optical micro-cavities [6] are contributing to the development of OFC sources. These efforts may open up the way to realise ultra-fast and stable optical clocks and pulsed sources with extremely high repetition-rates, in the form of compact and integrated devices. Indeed, the fabrication of high-quality factor (high-Q) micro-resonators, capable of dramatically amplifying the optical field, can be considered a photonics breakthrough that has boosted not only the scientific investigation of OFC sources [7-13] but also of optical sensors and compact light modulators [6,14]. In this framework, the demonstration of planar high-Q resonators, compatible with silicon technology [10-14], has opened up a unique opportunity for these devices to provide entirely new capabilities for photonic

Rationally designed porous silicon as platform for optical biosensors

International Nuclear Information System (INIS)

Priano, G.; Acquaroli, L.N.; Lasave, L.C.; Battaglini, F.; Arce, R.D.; Koropecki, R.R.

2012-01-01

Optical porous silicon multilayer structures are able to work as sensitive chemical sensors or biosensors based in their optical response. An algorithm to simulate the optical response of these multilayers was developed, considering the optical properties of the individual layers. The algorithm allows designing and customizing the porous silicon structures according to a given application. The results obtained by the simulation were experimentally verified; for this purpose different photonic structures were prepared, such as Bragg reflectors and microcavities. Some of these structures have been derivatized by the introduction of aminosilane groups on the porous silicon surface. The algorithm also permits to simulate the effects produced by a non uniform derivatization of the multilayer. - Highlights: ► Mesoporous silicon structure ► Functionalization of mesoporous silicon as sensors ► Design of the one-dimensional photonic crystal ► Simulation of non-uniformity in covering the sensor structure

Optical characterization and blu-ray recording properties of metal(II) azo barbituric acid complex films

Energy Technology Data Exchange (ETDEWEB)

Li, X.Y. [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)], E-mail: xyli@siom.ac.cn; Wu, Y.Q. [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Key Lab of Functional Inorganic Material Chemistry (Heilongjiang University), Ministry of Education, Haerbin 150080 (China)], E-mail: yqwu@siom.ac.cn; Gu, D.D.; Gan, F.X. [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

2009-02-25

Smooth thin films of nickel(II), cobalt(II) and zinc(II) complexes with azo barbituric acid were prepared by the spin-coating method. Absorption spectra of the thin films on K9 glass substrates in 300-700 nm wavelength region were measured. Optical constants (complex refractive index N = n + ik) of the thin films prepared on single-crystal silicon substrates in 275-695 nm wavelength region were investigated on rotating analyzer-polarizer type of scanning ellipsometer, and dielectric constant {epsilon} ({epsilon} = {epsilon}{sub 1} + i{epsilon}{sub 2}) as well as absorption coefficient {alpha} of thin films were calculated at 405 nm. In addition, static optical recording properties of the cobalt(II) complex thin film with an Ag reflective layer was carried out using a 406.7 nm blue-violet laser and a high numerical aperture (NA) of 0.90. Clear recording marks with high reflectivity contrast (>60%) at proper laser power and pulse width were obtained, and the size of recording mark was as small as 250 nm. The results indicate that these metal(II) complexes are promising organic recording medium for the blu-ray optical storage system.

Fabrication of polymer microlenses on single mode optical fibers for light coupling

Science.gov (United States)

Zaboub, Monsef; Guessoum, Assia; Demagh, Nacer-Eddine; Guermat, Abdelhak

2016-05-01

In this paper, we present a technique for producing fibers optics micro-collimators composed of polydimethylsiloxane PDMS microlenses of different radii of curvature. The waist and working distance values obtained enable the optimization of optical coupling between optical fibers, fibers and optical sources, and fibers and detectors. The principal is based on the injection of polydimethylsiloxane (PDMS) into a conical micro-cavity chemically etched at the end of optical fibers. A spherical microlens is then formed that is self-centered with respect to the axis of the fiber. Typically, an optimal radius of curvature of 10.08 μm is obtained. This optimized micro-collimator is characterized by a working distance of 19.27 μm and a waist equal to 2.28 μm for an SMF 9/125 μm fiber. The simulation and experimental results reveal an optical coupling efficiency that can reach a value of 99.75%.

The Unique Optical Design of the CTI-II Survey Telescope

Science.gov (United States)

Ackermann, Mark R.; McGraw, J. T.; MacFarlane, M.

2006-12-01

The CCD/Transit Instrument with Innovative Instrumentation (CTI-II) is being developed for precision ground-based astrometric and photometric astronomical observations. The 1.8m telescope will be stationary, near-zenith pointing and will feature a CCD-mosaic array operated in time-delay and integrate (TDI) mode to image a continuous strip of the sky in five bands. The heart of the telescope is a Nasmyth-like bent-Cassegrain optical system optimized to produce near diffraction-limited images with near zero distortion over a circular1.42 deg field. The optical design includes an f/2.2 parabolic ULE primary with no central hole salvaged from the original CTI telescope and adds the requisite hyperbolic secondary, a folding flat and a highly innovative all-spherical, five lens corrector which includes three plano surfaces. The reflective and refractive portions of the design have been optimized as individual but interdependent systems so that the same reflective system can be used with slightly different refractive correctors. At present, two nearly identical corrector designs are being evaluated, one fabricated from BK-7 glass and the other of fused silica. The five lens corrector consists of an air-spaced triplet separated from follow-on air-spaced doublet. Either design produces 0.25 arcsecond images at 83% encircled energy with a maximum of 0.0005% distortion. The innovative five lens corrector design has been applied to other current and planned Cassegrain, RC and super RC optical systems requiring correctors. The basic five lens approach always results in improved performance compared to the original designs. In some cases, the improvement in image quality is small but includes substantial reductions in distortion. In other cases, the improvement in image quality is substantial. Because the CTI-II corrector is designed for a parabolic primary, it might be especially useful for liquid mirror telescopes. We describe and discuss the CTI-II optical design with respect

Coherent response of a semiconductor microcavity in the strong coupling regime

Science.gov (United States)

Cassabois, G.; Triques, A. L. C.; Ferreira, R.; Delalande, C.; Roussignol, Ph; Bogani, F.

2000-05-01

We have studied the coherent dynamics of a semiconductor microcavity by means of interferometric correlation measurements with subpicosecond time resolution in a backscattering geometry. Evidence is brought of the resolution of a homogeneous polariton line in an inhomogeneously broadened exciton system. Surprisingly, photon-like polaritons exhibit an inhomogeneous dephasing. Moreover, we observe an unexpected stationary coherence up to 8 ps for the lower polariton branch close to resonance. All these experimental results are well reproduced within the framework of a linear dispersion theory assuming a coherent superposition of the reflectivity and resonant Rayleigh scattering signals with a well-defined relative phase.

Spatial confinement of acoustic and optical waves in stubbed slab structure as optomechanical resonator

Energy Technology Data Exchange (ETDEWEB)

Li, Changsheng, E-mail: lcs135@163.com; Huang, Dan; Guo, Jierong

2015-02-20

We theoretically demonstrate that acoustic waves and optical waves can be spatially confined in the same micro-cavity by specially designed stubbed slab structure. The proposed structure presents both phononic and photonic band gaps from finite element calculation. The creation of cavity mode inside the band gap region provides strong localization of phonon and photon in the defect region. The practical parameters to inject cavity and work experimentally at telecommunication range are discussed. This structure can be precisely fabricated, hold promises to enhance acousto-optical interactions and design new applications as optomechanical resonator. - Highlights: • A resonator simultaneously supports acoustic and optical modes. • Strong spatial confinement and slow group velocity. • Potential to work as active optomechanical resonator.

Influence of multi-exciton correlations on nonlinear polariton dynamics in semiconductor microcavities

International Nuclear Information System (INIS)

Wen, P; Nelson, Keith A; Christmann, G; Baumberg, J J

2013-01-01

Using two-dimensional spectroscopy, we resolve multi-polariton coherences in quantum wells embedded inside a semiconductor microcavity and elucidate how multi-exciton correlations mediate polariton nonlinear dynamics. We find that polariton correlation strengths depend on spectral overlap with the biexciton resonance and that up to at least four polaritons can be correlated, a higher-order correlation than observed to date among excitons in bare quantum wells. The high-order correlations can be attributed to coupling through the cavity mode, although the role of high-order Coulomb correlations cannot be excluded. (paper)

Rationally designed porous silicon as platform for optical biosensors

Energy Technology Data Exchange (ETDEWEB)

Priano, G. [INQUIMAE, DQIAyQF, FCEN, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon 2 (C1428EHA) Buenos Aires (Argentina); Acquaroli, L.N.; Lasave, L.C. [Instituto De Desarrollo Tecnologico Para La Industria Quimica, UNL, CONICET, Gueemes 3450 (S3000GLN) Santa Fe (Argentina); Battaglini, F. [INQUIMAE, DQIAyQF, FCEN, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon 2 (C1428EHA) Buenos Aires (Argentina); Arce, R.D., E-mail: rarce@intec.unl.edu.ar [Instituto De Desarrollo Tecnologico Para La Industria Quimica, UNL, CONICET, Gueemes 3450 (S3000GLN) Santa Fe (Argentina); Departamento De Materiales, Facultad De Ingenieria Quimica, UNL, Santiago del Estero 2829 (S3000) Santa Fe (Argentina); Koropecki, R.R. [Instituto De Desarrollo Tecnologico Para La Industria Quimica, UNL, CONICET, Gueemes 3450 (S3000GLN) Santa Fe (Argentina); Departamento De Materiales, Facultad De Ingenieria Quimica, UNL, Santiago del Estero 2829 (S3000) Santa Fe (Argentina)

2012-08-01

Optical porous silicon multilayer structures are able to work as sensitive chemical sensors or biosensors based in their optical response. An algorithm to simulate the optical response of these multilayers was developed, considering the optical properties of the individual layers. The algorithm allows designing and customizing the porous silicon structures according to a given application. The results obtained by the simulation were experimentally verified; for this purpose different photonic structures were prepared, such as Bragg reflectors and microcavities. Some of these structures have been derivatized by the introduction of aminosilane groups on the porous silicon surface. The algorithm also permits to simulate the effects produced by a non uniform derivatization of the multilayer. - Highlights: Black-Right-Pointing-Pointer Mesoporous silicon structure Black-Right-Pointing-Pointer Functionalization of mesoporous silicon as sensors Black-Right-Pointing-Pointer Design of the one-dimensional photonic crystal Black-Right-Pointing-Pointer Simulation of non-uniformity in covering the sensor structure.

Analysis of Plasmonics Based Fiber Optic Sensing Structures

Science.gov (United States)

Moayyed, Hamed

The work described in this PhD Thesis focuses on the post-processing of optical fibers and their enhancement as sensing element. Since the majority of sensors presented are based in Fabry-Perot interferometers, an historical overview of this category of optical fiber sensors is firstly presented. This review considers the works published since the early years, in the beginning of the 1980s, until the middle of 2015. The incorporation of microcavities at the tip of a single mode fiber was extensively studied, particularly for the measurement of nitrogen and methane gas pressure. These cavities were fabricated using hollow core silica tubes and a hollow core photonic crystal fiber. Following a different approach, the microcavities were incorporated between two sections of single mode fiber. In this case, the low sensitivity to temperature makes these microcavities highly desirable for the measurement of strain at high temperatures. Competences in post-processing techniques such as the chemical etching and the writing of periodical structures in the fiber core by means of an excimer or a femtosecond laser were also acquired in the course of the PhD programme. One of the works consisted in the design and manufacturing of a double clad optical fiber. The refractive index of the inner cladding was higher than the one of the outer cladding and the core. Thus, light was guided in the inner cladding instead of propagating in the core. This situation was overcome by applying chemical etching, thus removing the inner cladding. The core, surrounded by air, was then able to guide light. Two different applications were found for this fiber, as a temperature sensor and as an optical refractometer. In the last, the optical phase changes with the liquid refractive index. Two different types of fiber Bragg gratings were characterized in strain and temperature. Sensing structures obtained through the phase mask technique at the tip of an optical fiber were subjected to chemical

Simultaneously improving optical absorption of both transverse-electric polarized and transverse-magnetic polarized light for organic solar cells with Ag grating used as transparent electrode

Directory of Open Access Journals (Sweden)

Yongbing Long

2014-08-01

Full Text Available Theoretical simulations are performed to investigate optical performance of organic solar cells with Ag grating electrode. It is demonstrated that optical absorption for both transverse-electric (TE polarized and transverse-magnetic(TM polarized light is simultaneously improved when compared with that for the device without the Ag grating. The improvement is respectively attributed to the resonance and the surface plasmon polaritons within the device. After an additional WO3 layer is capped on the Ag grating, absorption of TE-polarized light is further improved due to resonance of double microcavities within the device, and absorption of TM-polarized light is improved by the combined effects of the microcavity resonance and the surface plasmon polaritons. Correspondingly, the short current density for randomly polarized light is improved by 18.1% from that of the device without the Ag grating. Finally, it is demonstrated that high transmission may not be an essential prerequisite for metallic gratings when they are used as transparent electrode since absorption loss caused by low transmission can be compensated by using a capping layer to optimize optical resonance of the WMC structure within the device.

Polarised two-photon excitation of quantum well excitons for manipulation of optically pumped terahertz lasers

Energy Technology Data Exchange (ETDEWEB)

Slavcheva, G., E-mail: gsk23@bath.ac.uk [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom); Kavokin, A.V., E-mail: A.Kavokin@soton.ac.uk [School of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Spin Optics Laboratory, St. Petersburg State University, 1, Ulyanovskaya 198504 (Russian Federation)

2014-11-15

Optical pumping of excited exciton states in a semiconductor quantum well embedded in a microcavity is a tool for realisation of ultra-compact terahertz (THz) lasers based on stimulated optical transition between excited (2p) and ground (1s) exciton state. We show that the probability of two-photon absorption by a 2p-exciton is strongly dependent on the polarisation of both pumping photons. Five-fold variation of the threshold power for terahertz lasing by switching from circular to co-linear pumping is predicted. We identify photon polarisation configurations for achieving maximum THz photon generation quantum efficiency.

All-optical switching based on a tunable Fano-like resonance in nonlinear ferroelectric photonic crystals

International Nuclear Information System (INIS)

Chai, Zhen; Hu, Xiaoyong; Gong, Qihuang

2013-01-01

A low-power all-optical switching is presented based on the all-optical tunable Fano-like resonance in a two-dimensional nonlinear ferroelectric photonic crystal made of polycrystalline lithium niobate. An asymmetric Fano-like line shape is achieved in the transmission spectrum by using two cascaded and uncoupled photonic crystal microcavities. The physical mechanism underlying the all-optical switching is attributed to the dynamic shift of the Fano-like resonance peak caused by variations in the dispersion relations of the photonic crystal structure induced by pump light. A large switching efficiency of 61% is reached under excitation of a weak pump light with an intensity as low as 1 MW cm −2 . (paper)

BCS-BEC crossover in a system of microcavity polaritons

International Nuclear Information System (INIS)

Keeling, Jonathan; Eastham, P.R.; Szymanska, M.H.; Littlewood, P.B.

2005-01-01

We investigate the thermodynamics and signatures of a polariton condensate over a range of densities, using a model of microcavity polaritons with internal structure. We determine a phase diagram for this system including fluctuation corrections to the mean-field theory. At low densities the condensation temperature T c behaves like that for point bosons. At higher densities, when T c approaches the Rabi splitting, T c deviates from the form for point bosons, and instead approaches the result of a BCS-like mean-field theory. This crossover occurs at densities much less than the Mott density. We show that current experiments are in a density range where the phase boundary is described by the BCS-like mean-field boundary. We investigate the influence of inhomogeneous broadening and detuning of excitons on the phase diagram

Final Report: Posttest Analysis of Omega II Optical Specimens

International Nuclear Information System (INIS)

Newlander, C D; Fisher, J H

2007-01-01

Preliminary posttest analyses have been completed on optical specimens exposed during the Omega II test series conducted on 14 July 2006. The Omega Facility, located at the Laboratory for Laser Energetics (LLE) at the University of Rochester was used to produce X-ray environments through the interaction of intense pulsed laser radiation upon germanium-loaded silica aerogels. The optical specimen testing was supported by GH Systems through experiment design, pre- and post-test analyses, specimen acquisition, and overall technical experience. The test specimens were fabricated and characterized by Surface Optics Corporation (SOC), San Diego, CA and were simple protected gold coatings on silica substrates. Six test specimens were exposed, five filtered with thin beryllium foil filters, and one unfiltered which was exposed directly to the raw environment. The experimental objectives were: (1) demonstrate that tests of optical specimens could be performed at the Omega facility; (2) evaluate the use and survivability of beryllium foil filters as a function of thickness; (3) obtain damage data on optical specimens which ranged from no damage to damage; (4) correlate existing thermal response models with the damage data; (5) evaluate the use of the direct raw environment upon the specimen response and the ability/desirability to conduct sensitive optical specimen tests using the raw environment; and (6) initiate the development of a protocol for performing optical coatings/mirror tests. This report documents the activities performed by GH Systems in evaluating and using the environments provided by LLNL, the PUFFTFT analyses performed using those environments, and the calculated results compared to the observed and measured posttest data

Solar radio bursts of spectral type II, coronal shocks, and optical coronal transients

Science.gov (United States)

Maxwell, A.; Dryer, M.

1981-01-01

An examination is presented of the association of solar radio bursts of spectral type II and coronal shocks with solar flare ejecta observed in H-alpha, the green coronal line, and white-light coronagraphs. It is suggested that fast-moving optical coronal transients should for the most part be identified with piston-type phenomena well behind the outward-traveling shock waves that generate type II radio bursts. A general model is presented which relates type II radio bursts and coronal shocks to optically observed ejecta and consists of three main velocity regimes: (1) a quasi-hemispherical shock wave moving outward from the flare at speeds of 1000-2000 km/sec and Alfven Mach number of about 1.5; (2) the velocity of the piston driving the shock, on the order of 0.8 that of the shock; and (3) the regime of the slower-moving H-alpha ejecta, with velocities of 300-500 km/sec.

Quantum Optics with Photonic Nanowires and Photonic Trumpets: Basics and Applications

DEFF Research Database (Denmark)

Gerard, J.; Claudon, J.; Munsch, M.

, the node of future quantum networks. Besides optical microcavities [1], photonic wires have recently demonstrated in this context an appealing potential [2, 3]. For instance, single photon sources (SPS) based on a single quantum dot in a vertical photonic wire with integrated bottom mirror and tapered tip...... have enabled for the ¯rst time to achieve simultaneously a very high e±ciency (0.72 photon per pulse) and a very pure single photon emission (g(2)(0) control of the spontaneous emission of embedded emitters [4...

Spin temperature concept verified by optical magnetometry of nuclear spins

Science.gov (United States)

Vladimirova, M.; Cronenberger, S.; Scalbert, D.; Ryzhov, I. I.; Zapasskii, V. S.; Kozlov, G. G.; Lemaître, A.; Kavokin, K. V.

2018-01-01

We develop a method of nonperturbative optical control over adiabatic remagnetization of the nuclear spin system and apply it to verify the spin temperature concept in GaAs microcavities. The nuclear spin system is shown to exactly follow the predictions of the spin temperature theory, despite the quadrupole interaction that was earlier reported to disrupt nuclear spin thermalization. These findings open a way for the deep cooling of nuclear spins in semiconductor structures, with the prospect of realizing nuclear spin-ordered states for high-fidelity spin-photon interfaces.

Pump-Power-Driven Mode Switching in a Microcavity Device and Its Relation to Bose-Einstein Condensation

Directory of Open Access Journals (Sweden)

H. A. M. Leymann

2017-06-01

Full Text Available We investigate the switching of the coherent emission mode of a bimodal microcavity device, occurring when the pump power is varied. We compare experimental data to theoretical results and identify the underlying mechanism based on the competition between the effective gain, on the one hand, and the intermode kinetics, on the other. When the pumping is ramped up, above a threshold, the mode with the largest effective gain starts to emit coherent light, corresponding to lasing. In contrast, in the limit of strong pumping, it is the intermode kinetics that determines which mode acquires a large occupation and shows coherent emission. We point out that this latter mechanism is akin to the equilibrium Bose-Einstein condensation of massive bosons. Thus, the mode switching in our microcavity device can be viewed as a minimal instance of Bose-Einstein condensation of photons. Moreover, we show that the switching from one cavity mode to the other always occurs via an intermediate phase where both modes are emitting coherent light and that it is associated with both superthermal intensity fluctuations and strong anticorrelations between both modes.

Multi-state lasing in self-assembled ring-shaped green fluorescent protein microcavities

Energy Technology Data Exchange (ETDEWEB)

Dietrich, Christof P., E-mail: cpd3@st-andrews.ac.uk; Höfling, Sven; Gather, Malte C., E-mail: mcg6@st-andrews.ac.uk [SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS (United Kingdom)

2014-12-08

We demonstrate highly efficient lasing from multiple photonic states in microcavities filled with self-assembled rings of recombinant enhanced green fluorescent protein (eGFP) in its solid state form. The lasing regime is achieved at very low excitation energies of 13 nJ and occurs from cavity modes dispersed in both energy and momentum. We attribute the momentum distribution to very efficient scattering of incident light at the surface of the eGFP rings. The distribution of lasing states in energy is induced by the large spectral width of the gain spectrum of recombinant eGFP (FWHM ≅ 25 nm)

Microcavity Plasma Devices and Arrays Fabricated in Semiconductor, Ceramic, or Metal/polymer Structures: A New Realm of Plasma Physics and Photonics Applications

International Nuclear Information System (INIS)

Eden, J. G.

2005-01-01

Micro discharge, or microcavity plasma, is the broad term that has come to be associated with an emerging class of glow discharge devices in which the characteristic spatial dimension of the plasma is nominally ) dia. Si wafers and operated in the rare gases and Ar/N2 gas mixtures. Also, photodetection in the ultraviolet, visible and near-infrared with microplasma devices has been observed by interfacing a low temperature plasma with a semiconductor. Carbon nanotubes grown directly within the microcavity of microplasma devices improve all key performance parameters of the device, and nanoporous Al2O3 grown onto Al by wet chemical processing yields microplasma devices of exceptional stability and lifetime. The opportunities such structures offer for accessing new avenues in plasma physics and photonics will be discussed. (Author)

A hybrid plasmonic microresonator with high quality factor and small mode volume

International Nuclear Information System (INIS)

Lu, Qijing; Chen, Daru; Wu, Genzhu; Peng, Baojin; Xu, Jiancheng

2012-01-01

We propose a novel hybrid plasmonic microcavity which is composed of a silver nanoring and a silica toroidal microcavity. The hybrid mode of the proposed hybrid plasmonic microcavity due to the coupling between the surface plasmon polaritons (SPPs) and the dielectric mode is demonstrated with a high quality factor (>1000) and an ultrasmall mode volume (∼0.8 μm 3 ). This microcavity shows great potential in fundamental studies of nonlinear optics and cavity quantum electrodynamics (cQED) and applications in low-threshold plasmonic microlasers. (paper)

Ultrafast optical control of individual quantum dot spin qubits.

Science.gov (United States)

De Greve, Kristiaan; Press, David; McMahon, Peter L; Yamamoto, Yoshihisa

2013-09-01

Single spins in semiconductor quantum dots form a promising platform for solid-state quantum information processing. The spin-up and spin-down states of a single electron or hole, trapped inside a quantum dot, can represent a single qubit with a reasonably long decoherence time. The spin qubit can be optically coupled to excited (charged exciton) states that are also trapped in the quantum dot, which provides a mechanism to quickly initialize, manipulate and measure the spin state with optical pulses, and to interface between a stationary matter qubit and a 'flying' photonic qubit for quantum communication and distributed quantum information processing. The interaction of the spin qubit with light may be enhanced by placing the quantum dot inside a monolithic microcavity. An entire system, consisting of a two-dimensional array of quantum dots and a planar microcavity, may plausibly be constructed by modern semiconductor nano-fabrication technology and could offer a path toward chip-sized scalable quantum repeaters and quantum computers. This article reviews the recent experimental developments in optical control of single quantum dot spins for quantum information processing. We highlight demonstrations of a complete set of all-optical single-qubit operations on a single quantum dot spin: initialization, an arbitrary SU(2) gate, and measurement. We review the decoherence and dephasing mechanisms due to hyperfine interaction with the nuclear-spin bath, and show how the single-qubit operations can be combined to perform spin echo sequences that extend the qubit decoherence from a few nanoseconds to several microseconds, more than 5 orders of magnitude longer than the single-qubit gate time. Two-qubit coupling is discussed, both within a single chip by means of exchange coupling of nearby spins and optically induced geometric phases, as well as over longer-distances. Long-distance spin-spin entanglement can be generated if each spin can emit a photon that is entangled

Absorptive lasing mode suppression in ZnO nano- and microcavities

Energy Technology Data Exchange (ETDEWEB)

Wille, M.; Michalsky, T.; Krüger, E.; Grundmann, M.; Schmidt-Grund, R. [Universität Leipzig, Institut für Experimentelle Physik II, Linnéstraße 5, 04103 Leipzig (Germany)

2016-08-08

We conclusively explain the different lasing mode energies in ZnO nano- and microcavities observed by us and reported in literature. The limited penetration depth of usually used excitation lasers results in an inhomogeneous spatial gain region depending on the structure size and geometry. Hence, weakly or even nonexcited areas remain present after excitation, where modes are instantaneously suppressed by excitonic absorption. We compare the effects for ZnO microwires, nanowires, and tetrapod-like structures at room temperature and demonstrate that the corresponding mode selective effect is most pronounced for whispering-gallery modes in microwires with a hexagonal cross section. Furthermore, the absorptive lasing mode suppression will be demonstrated by correlating the spot size of the excitation laser and the lasing mode characteristic of a single ZnO nanowire.

Matrix metalloproteinase sensing via porous silicon microcavity devices functionalized with human antibodies

Energy Technology Data Exchange (ETDEWEB)

Martin, Marta; Gergely, Csilla [GES-UMR 5650, CNRS, Universite Montpellier 2, Pl. Eugene Bataillon 34095, Montpellier Cedex 5 (France); Taleb Bendiab, Chakib; Massif, Laurent; Cuisinier, Frederic [EA4203, Faculte d' Odontologie, Universite Montpellier 1, Montpellier Cedex 5 (France); Palestino, Gabriela [Facultad de Ciencias Quimicas, Universidad Autonoma de San Luis Potosi, Av. Salvador Nava 6, 78000 San Luis Potosi (Mexico); Agarwal, Vivechana [CIICAP, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001, Col Chamilpa, Cuernavaca, Mor. (Mexico)

2011-06-15

Porous silicon microcavity (PSiMc) structures were used as support material for specific sensing of matrix metalloproteinases (MMPs). For lower concentrations of MMP-8, the structures were tested with two types of functionalization methods. Silanization of the oxidized porous silicon structures, followed by glutaraldehyde chemistry was found to give very inconsistent results. The use of biotinilated bovine serum albumin linked to the naked PSiMc was found to be an alternative method to attach the anti MMP-8 human antibody, previously modified with streptavidin, which was further used to sense MMP-8 (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Analysis of high-quality modes in open chaotic microcavities

International Nuclear Information System (INIS)

Fang, W.; Yamilov, A.; Cao, H.

2005-01-01

We present a numerical study of the high-quality modes in two-dimensional dielectric stadium microcavities. Although the classical ray mechanics is fully chaotic in a stadium billiard, all of the high-quality modes show a 'strong scar' around unstable periodic orbits. When the deformation (ratio of the length of the straight segments over the diameter of the half circles) is small, the high-quality modes correspond to whispering-gallery-type trajectories and their quality factors decrease monotonically with increasing deformation. At large deformation, each high-quality mode is associated with multiple unstable periodic orbits. Its quality factor changes nonmonotonically with the deformation, and there exists an optimal deformation for each mode at which its quality factor reaches a local maximum. This unusual behavior is attributed to the interference of waves propagating along different constituent orbits that could minimize light leakage out of the cavity

First results with a microcavity plasma panel detector

Energy Technology Data Exchange (ETDEWEB)

Ball, R. [University of Michigan, Department of Physics, Ann Arbor, MI 48109 (United States); Ben-Moshe, M.; Benhammou, Y.; Bensimon, R. [Tel Aviv University, School of Physics and Astronomy, Tel Aviv (Israel); Chapman, J.W. [University of Michigan, Department of Physics, Ann Arbor, MI 48109 (United States); Davies, M.; Etzion, E. [Tel Aviv University, School of Physics and Astronomy, Tel Aviv (Israel); Ferretti, C., E-mail: claudiof@umich.edu [University of Michigan, Department of Physics, Ann Arbor, MI 48109 (United States); Friedman, P.S. [Integrated Sensors, LLC, Ottawa Hills, OH 43606 (United States); Levin, D.S. [University of Michigan, Department of Physics, Ann Arbor, MI 48109 (United States); Silver, Y. [Tel Aviv University, School of Physics and Astronomy, Tel Aviv (Israel); Varner, R.L. [Oak Ridge National Laboratory, Physics Division, Oak Ridge, TN 737831 (United States); Weaverdyck, C.; Zhou, B. [University of Michigan, Department of Physics, Ann Arbor, MI 48109 (United States)

2015-06-01

A new type of gaseous micropattern particle detector based on a closed-cell microcavity plasma panel sensor is reported. The first device was fabricated with 1×1×2 mm cells. It has shown very clean signals of 0.6–2.5 V amplitude, fast rise time of approximately 2 ns and FWHM of about 2 ns with very uniform signal shapes across all pixels. From initial measurements with β particles from a radioactive source, a maximum pixel efficiency greater than 95% is calculated, for operation of the detector over a 100 V wide span of high voltages (HV). Over this same HV range, the background rate per pixel was measured to be 3–4 orders of magnitude lower than the rate with which the cell was illuminated by the β source. Pixel-to-pixel count rate uniformity is within 3% and stable within 3% for many days. The time resolution is 2.4 ns, and a very low cell-to-cell crosstalk has been measured between cells separated by 2 mm.

Seeding of Polariton Stimulation in a Homogeneously Broadened Microcavity

DEFF Research Database (Denmark)

Østergaard, John Erland; Langbein, Wolfgang Werner; Jensen, Jacob Riis

2000-01-01

In time-resolved light emission from a high-quality semiconductor microcavity after pulsed excitation suitable for angle-resonant polariton-polariton scattering on the lower-polariton branch, we find strong evidence for final-state stimulation of this process. The self-stimulated emission...... and the intensity of this emission can be controlled. The time-resolved data and the density dependences are in agreement with a rate equation model neglecting polarization mixing effects. This model gives a coupling coefficient of b(LP,k)=0 = 2.4 x 10(-9) cm(4) s(-1) for the stimulated angle-resonant polariton......, following single-pulse excitation, appears on a fast time scale of only a few lens of ps with a maximum at 15 ps. This is in striking contrast to the photoluminescence decay time of 110 ps observed in the low-density limit. By injection of polaritons into the final state by a seeding pulse, the dynamics...

Mass and Momentum Transport in Microcavities for Diffusion-Dominant Cell Culture Applications

Science.gov (United States)

Yew, Alvin G.; Pinero, Daniel; Hsieh, Adam H.; Atencia, Javier

2012-01-01

For the informed design of microfluidic devices, it is important to understand transport phenomena at the microscale. This letter outlines an analytically-driven approach to the design of rectangular microcavities extending perpendicular to a perfusion microchannel for microfluidic cell culture devices. We present equations to estimate the spatial transition from advection- to diffusion-dominant transport inside cavities as a function of the geometry and flow conditions. We also estimate the time required for molecules, such as nutrients or drugs to travel from the microchannel to a given depth into the cavity. These analytical predictions can facilitate the rational design of microfluidic devices to optimize and maintain long-term, physiologically-based culture conditions with low fluid shear stress.

Performance of the upgraded LTP-II at the ALS Optical Metrology Laboratory

International Nuclear Information System (INIS)

Advanced Light Source; Yashchuk, Valeriy V; Kirschman, Jonathan L.; Domning, Edward E.; McKinney, Wayne R.; Morrison, Gregory Y.; Smith, Brian V.; Yashchuk, Valeriy V.

2008-01-01

The next generation of synchrotrons and free electron laser facilities requires x-ray optical systems with extremely high performance, generally of diffraction limited quality. Fabrication and use of such optics requires adequate, highly accurate metrology and dedicated instrumentation. Previously, we suggested ways to improve the performance of the Long Trace Profiler (LTP), a slope measuring instrument widely used to characterize x-ray optics at long spatial wavelengths. The main way is use of a CCD detector and corresponding technique for calibration of photo-response non-uniformity [J. L. Kirschman, et al., Proceedings of SPIE 6704, 67040J (2007)]. The present work focuses on the performance and characteristics of the upgraded LTP-II at the ALS Optical Metrology Laboratory. This includes a review of the overall aspects of the design, control system, the movement and measurement regimes for the stage, and analysis of the performance by a slope measurement of a highly curved super-quality substrate with less than 0.3 microradian (rms)slope variation

Optical and optoelectronic properties of nanostructures based on wide-bandgap semiconductors

International Nuclear Information System (INIS)

Kalden, Joachim

2010-01-01

Recently, more and more research is done on nitride nanostructures in order to control the electrical and optical properties in a more sophisticated manner for optimized light-matter-interaction and extraction efficiency. In this context, the work presented in this thesis has been carried out, concentrating on two main topics. One aspect is the characterization of InGaN quantum dots (QDs). QDs possess a unique atom-like density of states for electrons, allowing for generation and manipulation of discrete electronic states. This thesis contains the analysis of QDs embedded in optoelectronic devices such as LEDs. Measurements of the electroluminescence (EL) of QD ensembles as well as single QDs are presented. Especially QD EL obtained at higher temperatures up to 150 K is a main achievement of this work. Furthermore, the photoluminescence (PL) of QD multilayer structures has been examined and discussed in detail. Experiments on the optical amplification in these multilayers have been carried out for the first time, yielding a maximum optical gain of g(max)/(mod)=50/cm. Another main aspect of solid state lighting is the efficient light extraction from light sources. For this purpose, pillar microcavities based on nitrides have been investigated. This type of optical resonator possesses a discrete optical mode structure due to the three-dimensional optical confinement in these structures. For optimal light-matter coupling conditions, this leads to an enhanced extraction efficiency. In this context, studies on QD pillar microcavities (MCs) processed by focused ion beam milling from planar MC structures are presented. After a detailed analysis of the photonic properties of these pillar MCs, a temperature-variation method to tune the cavity in resonance with QD emission is demonstrated, yielding a five-fold enhancement of the extraction efficiency. These experiments were carried out on selenide-based structures which possess a very high structural quality. An alternative

Optical investigations and control of spindynamics in Mn doped II-VI quantum dots

International Nuclear Information System (INIS)

Schmidt, Thomas

2009-01-01

The present thesis deals with the spin of charge carriers confined in CdSe/ZnSe quantum dots (QDs) closely linked to the polarization of emitted photons. II-VI material systems can be adequately mixed with the B-group element manganese. Such semimagnetic nanostructures offer a number of characteristic optical and electronic features. This is caused by an exchange interaction between the spin of optically excited carriers and the 3d electrons of the Mn ions. Within the framework of this thesis addressing of well defined spin states was realized by optical excitation of charge carriers. The occupation of different spin states was detected by the degree of polarization of the emitted photoluminescence (PL) light. For that purpose different optical methods of time-resolved and time-integrated spectroscopy as well as investigations in magnetic fields were applied. (orig.)

Sensitive detection of individual neutral atoms in a strong coupling cavity QED system

International Nuclear Information System (INIS)

Zhang Pengfei; Zhang Yuchi; Li Gang; Du Jinjin; Zhang Yanfeng; Guo Yanqiang; Wang Junmin; Zhang Tiancai; Li Weidong

2011-01-01

We experimentally demonstrate real-time detection of individual cesium atoms by using a high-finesse optical micro-cavity in a strong coupling regime. A cloud of cesium atoms is trapped in a magneto-optical trap positioned at 5 mm above the micro-cavity center. The atoms fall down freely in gravitation after shutting off the magneto-optical trap and pass through the cavity. The cavity transmission is strongly affected by the atoms in the cavity, which enables the micro-cavity to sense the atoms individually. We detect the single atom transits either in the resonance or various detunings. The single atom vacuum-Rabi splitting is directly measured to be Ω = 2π × 23.9 MHz. The average duration of atom-cavity coupling of about 110 μs is obtained according to the probability distribution of the atom transits. (authors)

Improvement of PEP-II Linear Optics with a MIA-Derived Virtual Accelerator

International Nuclear Information System (INIS)

Cerio, B.; Colgate U.

2006-01-01

In several past studies, model independent analysis, in conjunction with a virtual accelerator model, has been successful in improving PEP-II linear geometric optics. In many cases, optics improvement yielded an increase in machine luminosity. In this study, an updated characterization of linear optics is presented. With the PEP-II beam position monitor (BPM) system, four independent beam centroid orbits were extracted and used to determine phase advances and linear Green's functions among BPM locations. A magnetic lattice model was then constructed with a singular value decomposition-enhanced least-square fitting of phase advances and Green's functions, which are functions of quadrupole strengths, sextupole feed-downs, as well as BPM errors, to the corresponding measured quantities. The fitting process yielded a machine model that matched the measured linear optics of the real machine and was therefore deemed the virtual accelerator. High beta beat, as well as linear coupling, was observed in both LER and HER of the virtual accelerator. Since there was higher beta beating in LER, focus was shifted to the improvement of this ring. By adjusting select quadrupoles of the virtual LER and fitting the resulting beta functions and phase advances to those of the desired lattice, the average beta beat of the virtual machine was effectively reduced. The new magnet configuration was dialed into LER on August 10, 2006, and beta beat was reduced by a factor of three. After fine tuning HER to match the improved LER for optimal collision, a record peak luminosity of 12.069 x 10 33 cm -2 s -1 was attained on August 16, 2006

Nonlinear optical properties of systems based on ruthenium(II) tetra-15-crown-5-phthalocyaninate

International Nuclear Information System (INIS)

Grishina, A.D.; Gorbunova, Yu.G.; Enakieva, Yu.Yu.; Krivenko, T.V.; Savel'ev, V.V.; Vannikov, A.V.; Tsivadze, A.Yu.

2008-01-01

The third-order nonlinear optical properties of the ruthenium (II) complex with tetra-15-crown-5-phthalocyanine and axially coordinated triethylenediamine molecules (R 4 Pc)Ru(TED) 2 were analyzed by means of the z-scanning technique. A solution of (R 4 Pc)Ru(TED) 2 in tetrachloroethane was exposed to nanosecond laser pulses at a wavelength of 1064 nm. It was found that the third-order molecular polarizability of the Ru(II) complex is 4.5 x 10 -32 cm 4 /C (esu). The polarizability per molecule increases by a factor of 3.6 when the single molecule occurs in a supramolecular assembly of (R 4 Pc)Ru(TED) 2 complexes. The photoelectric and photorefractive properties at 1064 nm of polymer composites, determined by the supramolecular assemblies that exhibits optical absorption and photoelectric sensitivity in the near IR region, are reported [ru

Optical fiber sensors technology for supervision, control and protection of high power systems

Science.gov (United States)

Nascimento, Ivo Maciel

The work described in this PhD Thesis focuses on the post-processing of optical fibers and their enhancement as sensing element. Since the majority of sensors presented are based in Fabry-Perot interferometers, an historical overview of this category of optical fiber sensors is firstly presented. This review considers the works published since the early years, in the beginning of the 1980s, until the middle of 2015. The incorporation of microcavities at the tip of a single mode fiber was extensively studied, particularly for the measurement of nitrogen and methane gas pressure. These cavities were fabricated using hollow core silica tubes and a hollow core photonic crystal fiber. Following a different approach, the microcavities were incorporated between two sections of single mode fiber. In this case, the low sensitivity to temperature makes these microcavities highly desirable for the measurement of strain at high temperatures. Competences in post-processing techniques such as the chemical etching and the writing of periodical structures in the fiber core by means of an excimer or a femtosecond laser were also acquired in the course of the PhD programme. One of the works consisted in the design and manufacturing of a double clad optical fiber. The refractive index of the inner cladding was higher than the one of the outer cladding and the core. Thus, light was guided in the inner cladding instead of propagating in the core. This situation was overcome by applying chemical etching, thus removing the inner cladding. The core, surrounded by air, was then able to guide light. Two different applications were found for this fiber, as a temperature sensor and as an optical refractometer. In the last, the optical phase changes with the liquid refractive index. Two different types of fiber Bragg gratings were characterized in strain and temperature. Sensing structures obtained through the phase mask technique at the tip of an optical fiber were subjected to chemical

Modeling of optical fields in laser microcavities using a modal method

DEFF Research Database (Denmark)

Gregersen, Niels

2013-01-01

mechanism limiting the Q factor is the poor modal overlap between the cavity Bloch mode and the mirror Bloch mode. Also, the strong connement will generally lead to highly divergent far field patterns and thus low collection efficiency. In this scenario, Bloch-wave engineering [1] and the introduction...... of adiabatic transitions emerge as powerful design tools to control the optical mode. In the modal method, the eld is expanded on the eigenmodes of z-invariant layers and on the Bloch modes of periodic sections. Using mode matching at the interfaces, the method gives direct access to re ection and transmission...

Neuro-evolutionary computing paradigm for Painlevé equation-II in nonlinear optics

Science.gov (United States)

Ahmad, Iftikhar; Ahmad, Sufyan; Awais, Muhammad; Ul Islam Ahmad, Siraj; Asif Zahoor Raja, Muhammad

2018-05-01

The aim of this study is to investigate the numerical treatment of the Painlevé equation-II arising in physical models of nonlinear optics through artificial intelligence procedures by incorporating a single layer structure of neural networks optimized with genetic algorithms, sequential quadratic programming and active set techniques. We constructed a mathematical model for the nonlinear Painlevé equation-II with the help of networks by defining an error-based cost function in mean square sense. The performance of the proposed technique is validated through statistical analyses by means of the one-way ANOVA test conducted on a dataset generated by a large number of independent runs.

Miniature Optical Isolator, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — To address NASA's need for compact optical isolators, Physical Optics Corporation (POC) proposes to continue the development of a new Miniature Optical Isolator...

Development of a Novel Fiber Optic Sensor Combined with a Fluorescence Turn-on Probe for Cu (II Detection

Directory of Open Access Journals (Sweden)

Ma J.

2013-04-01

Full Text Available Existing staining-based methodology for the detection of metal ions is not well suited for real-time or in situ use. This is a significant problem, given that these ions can have a considerable impact on both human health and the environment. Thus, there is growing interest and need for simple, rapid and in-situ monitoring techniques for the purpose of detecting various target analytes (e.g. heavy metals, which is of a significant importance in many fields ranging from environmental monitoring to the study of intracellular processes. Among various sensors developed, optical fiber-optic sensors (FOS, based on fluorescence, are one class of sensors that address this goal [1]. Optical fibers are ideal for environmental sensing applications because of their ability to transmit optical signals to and from the sensing region without the use of free-space optics. In this work, we present, for the first time, a simple FOS incorporating novel fluorescence turn-on mechanism [2] that could detect Cu (II as low as 10−4 M. Traditionally, fluorescence quenching or “turn-off” was used to detect Cu (II [3]. In recent years, fluorescence “turn-on” emerges as a preferable tool. The developed fiber-optic sensor has two fiber leads and one probe head. One fiber lead includes 6 fibers for He-Ne laser excitation light delivery (e-fibers. Another fiber lead has one receiving fiber (r-fiber connected to an Ocean Optics QE65000 scientific grade spectrometer, which is interrogated by a computer via USB connection. The SpectroSuite software is used to observe and to record all spectra. The probe head combines all fibers together to form a coaxial structure with the r-fiber placed in the center. The key component in the proposed fluorescent sensing system is a probe prepared by binding a receptor containing a zwitterionic chromophore (M1, through noncovalent interactions, to the fluorescent polymer (P1 resulting in quenching its emission. The sensing mechanism

Optical fiber chemiluminescence sensor for iron (II) ion based on immobilized luminol

International Nuclear Information System (INIS)

Alipao, Arthur A.; Sevilla, Fortunato III.

1999-01-01

A chemiluminescence (CL) sensor for iron (II) was developed based on the catalytic action of the analyte on the CL reaction between luminol and oxygen. The reagents were immobilized on a cellulose membrane and set on a reaction cell which was coupled by means of an optical fiber to a spectrofluorometer. The concentration of iron(II) was quantified by measuring the intensity of the light generated from the CL reaction. The response of the sensor system was rapid and highly reproducible. Good sensitivity was displayed by the sensor system over the five orders of magnitude of iron(II) ion concentration. The calibration curve consisted of two portions: (1) a linear range at lower concentrations (7.5 x 10 -7 M to 1.0 x 10 -4 M) exhibiting a positive slope arising from a catalytic action, and (2) a linear range at higher concentrations (5.0 x 10 -2 M to 2.5 x 10 -4 M) wherein the slope is negative due to an inhibitory action of iron(II) on the CL reaction. The sensor system was highly selective for iron(II) ions. (Author)

Proceedings of the OPTELACIC 2009. VI International TECNOLASER Event. II Meeting of Optic, Life and Heritage

International Nuclear Information System (INIS)

2009-04-01

The Center of Applied Technologies and Nuclear Development (CEADEN) and the Cuban Physical Society (SCF) celebrated the VI International Workshop Tecnolaser, T ECNOLASER 2009 , and the II International Meeting Optics, Life and Heritage in the CAPITOLIO, Havana, Cuba, the week of 13-16 April 2009, under the general lemma O ptics and Laser Technology in Science, Industry and Culture . Main Topics for Tecnolaser Session: Laser technology, optics, processing of images, and spectroscopy in medicine, biology, chemistry, nonotechnology and industry; Electronics, mechanics and automation associated to optics and laser techniques; Development and construction of laser installations, instruments and optic elements; Optoelectronic, photonic and fiber optic; Processing of materials with laser; Optic techniques of measurement and spectroscopy and Optic tweezers. Main Topics for Optics, Life and Heritage: Optics and Light in Life Sciences; Environmental Analysis by Means of Optics, Image Processing, or Laser spectroscopy; Optics, Laser, Image Processing or Spectroscopy in Heritage Conservation and Restauration; Optics and Holography in Art; Archaeological and Museological Optics Applications; Hand drawn holography and Biophotonic

Effective slip over partially filled microcavities and its possible failure

Science.gov (United States)

Ge, Zhouyang; Holmgren, Hanna; Kronbichler, Martin; Brandt, Luca; Kreiss, Gunilla

2018-05-01

Motivated by the emerging applications of liquid-infused surfaces (LIS), we study the drag reduction and robustness of transverse flows over two-dimensional microcavities partially filled with an oily lubricant. Using separate simulations at different scales, characteristic contact line velocities at the fluid-solid intersection are first extracted from nanoscale phase field simulations and then applied to micronscale two-phase flows, thus introducing a multiscale numerical framework to model the interface displacement and deformation within the cavities. As we explore the various effects of the lubricant-to-outer-fluid viscosity ratio μ˜2/μ˜1 , the capillary number Ca, the static contact angle θs, and the filling fraction of the cavity δ , we find that the effective slip is most sensitive to the parameter δ . The effects of μ˜2/μ˜1 and θs are generally intertwined but weakened if δ 1 ), however, are immune to such failure due to their generally larger contact line velocity.

Analysis of ultra-high sensitivity configuration in chip-integrated photonic crystal microcavity bio-sensors

International Nuclear Information System (INIS)

Chakravarty, Swapnajit; Hosseini, Amir; Xu, Xiaochuan; Zhu, Liang; Zou, Yi; Chen, Ray T.

2014-01-01

We analyze the contributions of quality factor, fill fraction, and group index of chip-integrated resonance microcavity devices, to the detection limit for bulk chemical sensing and the minimum detectable biomolecule concentration in biosensing. We analyze the contributions from analyte absorbance, as well as from temperature and spectral noise. Slow light in two-dimensional photonic crystals provide opportunities for significant reduction of the detection limit below 1 × 10 −7 RIU (refractive index unit) which can enable highly sensitive sensors in diverse application areas. We demonstrate experimentally detected concentration of 1 fM (67 fg/ml) for the binding between biotin and avidin, the lowest reported till date

Anisotropic exchange interaction induced by a single photon in semiconductor microcavities

Science.gov (United States)

Chiappe, G.; Fernández-Rossier, J.; Louis, E.; Anda, E. V.

2005-12-01

We investigate coupling of localized spins in a semiconductor quantum dot embedded in a microcavity. The lowest cavity mode and the quantum dot exciton are coupled and close in energy, forming a polariton. The fermions forming the exciton interact with localized spins via exchange. Exact diagonalization of a Hamiltonian in which photons, spins, and excitons are treated quantum mechanically shows that a single polariton induces a sizable indirect anisotropic exchange interaction between spins. At sufficiently low temperatures strong ferromagnetic correlations show up without an appreciable increase in exciton population. In the case of a (Cd,Mn)Te quantum dot, Mn-Mn ferromagnetic coupling is still significant at 1 K : spin-spin correlation around 3 for exciton occupation smaller than 0.3. We find that the interaction mediated by photon-polaritons is 10 times stronger than the one induced by a classical field for equal Rabi splitting.

Growth of self-assembled (Ga)InAs/GaAs quantum dots and realization of high quality microcavities for experiments in the field of strong exciton photon coupling

International Nuclear Information System (INIS)

Loeffler, Andreas

2008-01-01

At the beginning, we improved the three dimensional optical confinement of the micropillars. The quality factor of the pillars could be increased by the use of higher reflectivity mirrors and a matched V/III ratio for the different epitaxial layers. Hence, a record quality factor of about 90000 was achieved for an active micropillar with 26 (30) mirror pairs in the top (bottom) DBR and a diameter of 4 μm. In parallel to this, we made studies on the growth of self-assembled GaInAs quantum dots on GaAs substrates. Here, the nucleation of three dimensional islands as well as their optical properties were object of the investigation. The morphological properties of the dots were analyzed by transmission and scanning electron microscopy, and the optical properties were investigated by photoluminescence and photoreflectance measurements. The optical and particularly the morphological properties of the self-assembled GaInAs quantum dots were essentially improved. Due to a low strain nucleation layer with an indium content of 30 %, the dot density could be reduced to 6-9 x 10 9 cm -2 and their geometric dimensions were increased to typical lengths between 50 and 100 nm and widths of about 30 nm. The lattice mismatch between the quantum dots and the surrounding matrix is decreased due to the reduced indium content. The minimized strain during the dot growth leads to an enhanced migration length of the deposited atoms on the surface. Finally, the obtained findings of the MBE growth of microcavities, their fabrication and the self-assembled island growth of GaInAs on GaAs were used for the realization of further samples. Low strain GaInAs quantum dots were embedded into the microresonators. These structures allowed for the first time the observation of strong coupling between light and matter in a semiconductor. In case of the low strain quantum dots with enlarged dimensions in the strong coupling regime, a vacuum Rabi-splitting of about 140 μeV between the cavity mode and

Analysis of ultra-high sensitivity configuration in chip-integrated photonic crystal microcavity bio-sensors

Energy Technology Data Exchange (ETDEWEB)

Chakravarty, Swapnajit, E-mail: swapnajit.chakravarty@omegaoptics.com; Hosseini, Amir; Xu, Xiaochuan [Omega Optics, Inc., Austin, Texas 78757 (United States); Zhu, Liang; Zou, Yi [Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, Texas 78758 (United States); Chen, Ray T., E-mail: raychen@uts.cc.utexas.edu [Omega Optics, Inc., Austin, Texas 78757 (United States); Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, Texas 78758 (United States)

2014-05-12

We analyze the contributions of quality factor, fill fraction, and group index of chip-integrated resonance microcavity devices, to the detection limit for bulk chemical sensing and the minimum detectable biomolecule concentration in biosensing. We analyze the contributions from analyte absorbance, as well as from temperature and spectral noise. Slow light in two-dimensional photonic crystals provide opportunities for significant reduction of the detection limit below 1 × 10{sup −7} RIU (refractive index unit) which can enable highly sensitive sensors in diverse application areas. We demonstrate experimentally detected concentration of 1 fM (67 fg/ml) for the binding between biotin and avidin, the lowest reported till date.

Entropic Lattice Boltzmann study of hydrodynamics in a microcavity - Part 1

Energy Technology Data Exchange (ETDEWEB)

Karlin, I. V.; Ansumali, S.; Frouzakis, Ch. E.; Boulouchos, K. [Eidgenoessische Technische Hochschule (ETH), Labor fuer Aerothermochemie und Verbrennungssysteme ETHZ, ETH-Zentrum, Zuerich (Switzerland)

2005-07-01

This yearly report for 2004 presents a review of work being done on behalf of the Swiss Federal Office of Energy (SFOE) at the Laboratory for Aero-thermochemistry and Combustion Systems at the Federal Institute of Technology ETH in Zurich, Switzerland, on the development of a new approximation method for use in micrometer-scale flow calculations. The method, based on recently-developed so-called minimal entropy-kinetic models of the Boltzmann-kinetic equation, is discussed. Two detailed studies of micro-flows in specific geometries are discussed. The potential of the new method as a replacement for costly microscopic simulation methods is examined. The development and testing of a new thermal model - the so-called Thermal D2Q9 model - is discussed. A second study examined flows in a micro-cavity. A detailed parametric study of the quantitative and qualitative properties of the flows for a comprehensive range of dilution is mentioned.

Turnable Semiconductor Laser Spectroscopy in Hollow Optical Waveguides, Phase II SBIR

Energy Technology Data Exchange (ETDEWEB)

Gregory J. Fetzer, Ph.D.

2001-12-24

In this study a novel optical trace gas sensor based on a perforated hollow waveguide (PHW) was proposed. The sensor has been given the acronym ESHOW for Environmental Sensor using Hollow Optical Waveguides. Realizations of the sensor have demonstrated rapid response time (<2s), low minimum detection limits (typically around 3 x 10-5 absorbance). Operation of the PHW technology has been demonstrated in the near-infrared (NIR) and mid0infrared (MIR) regions of the spectrum. Simulation of sensor performance provided in depth understanding of the signals and signal processing required to provide high sensitivity yet retain rapid response to gas changes. A dedicated sensor electronics and software foundation were developed during the course of the Phase II effort. Commercial applications of the sensor are ambient air and continuous emissions monitoring, industrial process control and hazardous waste site monitoring. There are numerous other applications for such a sensor including medical diagnosis and treatment, breath analysis for legal purposes, water quality assessment, combustion diagnostics, and chemical process control. The successful completion of Phase II resulted in additional funding of instrument development by the Nations Institute of Heath through a Phase I SBIR grant and a strategic teaming relationship with a commercial manufacture of medical instrumentation. The purpose of the NIH grant and teaming relationship is to further develop the sensor to monitor NO in exhaled breath for the purposes of asthma diagnosis.

Simulations of emission from microcavity tandem organic light-emitting diodes

International Nuclear Information System (INIS)

Biswas, Rana; Xu, Chun; Zhao, Weijun; Liu, Rui; Shinar, Ruth; Shinar, Joseph

2011-01-01

Microcavity tandem organic light-emitting diodes (OLEDs) are simulated and compared to experimental results. The simulations are based on two complementary techniques: rigorous finite element solutions of Maxwell's equations and Fourier space scattering matrix solutions. A narrowing and blue shift of the emission spectrum relative to the noncavity single unit OLED is obtained both theoretically and experimentally. In the simulations, a distribution of emitting sources is placed near the interface of the electron transport layer tris(8-hydroxyquinoline) Al (Alq 3 ) and the hole transport layer (N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)benzidine) (α-NPB). Far-field electric field intensities are simulated. The simulated widths of the emission peaks also agree with the experimental results. The simulations of the 2-unit tandem OLEDs shifted the emission to shorter wavelength, in agreement with experimental measurements. The emission spectra's dependence on individual layer thicknesses also agreed well with measurements. Approaches to simulate and improve the light emission intensity from these OLEDs, in particular for white OLEDs, are discussed.

Ultrafast all-optical order-to-chaos transition in silicon photonic crystal chips

KAUST Repository

Bruck, Roman

2016-06-08

The interaction of light with nanostructured materials provides exciting new opportunities for investigating classical wave analogies of quantum phenomena. A topic of particular interest forms the interplay between wave physics and chaos in systems where a small perturbation can drive the behavior from the classical to chaotic regime. Here, we report an all-optical laser-driven transition from order to chaos in integrated chips on a silicon photonics platform. A square photonic crystal microcavity at telecom wavelengths is tuned from an ordered into a chaotic regime through a perturbation induced by ultrafast laser pulses in the ultraviolet range. The chaotic dynamics of weak probe pulses in the near infrared is characterized for different pump-probe delay times and at various positions in the cavity, with high spatial accuracy. Our experimental analysis, confirmed by numerical modelling based on random matrices, demonstrates that nonlinear optics can be used to control reversibly the chaotic behavior of light in optical resonators. (Figure presented.) . © 2016 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

The Intrinsically X-Ray-weak Quasar PHL 1811. II. Optical and UV Spectra and Analysis

Science.gov (United States)

Leighly, Karen M.; Halpern, Jules P.; Jenkins, Edward B.; Casebeer, Darrin

2007-11-01

This is the second of two papers reporting observations and analysis of the unusually bright (mb=14.4), luminous (MB=-25.5), nearby (z=0.192) narrow-line quasar PHL 1811. The first paper reported that PHL 1811 is intrinsically X-ray-weak and presented a spectral energy distribution (SED). Here we present HST STIS optical and UV spectra, and ground-based optical spectra. The optical and UV line emission is very unusual. There is no evidence for forbidden or semiforbidden lines. The near-UV spectrum is dominated by very strong Fe II and Fe III, and unusual low-ionization lines such as Na I D and Ca II H and K are observed. High-ionization lines are very weak; C IV has an equivalent width of 6.6 Å, a factor of ~5 smaller than measured from quasar composite spectra. An unusual feature near 1200 Å can be deblended in terms of Lyα, N V, Si II, and C III* using the blueshifted C IV profile as a template. Photoionization modeling shows that the unusual line emission can be explained qualitatively by the unusually soft SED. Principally, a low gas temperature results in inefficient emission of collisionally excited lines, including the semiforbidden lines generally used as density diagnostics. The emission resembles that of high-density gas; in both cases this is a consequence of inefficient cooling. PHL 1811 is very unusual, but we note that quasar surveys may be biased against finding similar objects. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. These observations are associated with proposal 9181. Based on observations obtained at Kitt Peak National Observatory, a division of the National Optical Astronomy Observatories, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.

Influence of post-deposition annealing on structural, morphological and optical properties of copper (II) acetylacetonate thin films.

Science.gov (United States)

Abdel-Khalek, H; El-Samahi, M I; El-Mahalawy, Ahmed M

2018-05-21

In this study, the effect of thermal annealing under vacuum conditions on structural, morphological and optical properties of thermally evaporated copper (II) acetylacetonate, cu(acac) 2 , thin films were investigated. The copper (II) acetylacetonate thin films were deposited using thermal evaporation technique at vacuum pressure ~1 × 10 -5  mbar. The deposited films were thermally annealed at 323, 373, 423, and 473 K for 2 h in vacuum. The thermogravimetric analysis of cu(acac) 2 powder indicated a thermal stability of cu(acac) 2 up to 423 K. The effects of thermal annealing on the structural properties of cu(acac) 2 were evaluated employing X-ray diffraction method and the analysis showed a polycrystalline nature of the as-deposited and annealed films with a preferred orientation in [1¯01] direction. Fourier transformation infrared (FTIR) technique was used to negate the decomposition of copper (II) acetylacetonate during preparation or/and annealing up to 423 K. The surface morphology of the prepared films was characterized by means of field emission scanning electron microscopy (FESEM). A significant enhancement of the morphological properties of cu(acac) 2 thin films was obtained till the annealing temperature reaches 423 K. The variation of optical constants that estimated from spectrophotometric measurements of the prepared thin films was investigated as a function of annealing temperature. The annealing process presented significantly impacted the nonlinear optical properties such as third-order optical susceptibility χ (3) and nonlinear refractive index n 2 of cu(acac) 2 thin films. Copyright © 2018 Elsevier B.V. All rights reserved.

Preface

Science.gov (United States)

2003-10-01

polariton branch to allow much of the new physics in semiconductor microcavities. Non-linear effects in semiconductor microcavities, which include stimulated polariton scattering, parametric oscillation, spin dynamics, and the possibilities of a polariton condensate, are discussed by Baumberg et al. The suppression of the relaxation bottleneck on the lower polariton branch and the stimulation of the emission in II-VI based microcavities is demonstrated by Dang and collaborators, who also probe the coherent dynamics along the lower polariton branch by means of angle-resolved four wave mixing experiments. The possibility to observe parametric polariton amplification at room temperature is discussed by Deveaud's team, who demonstrate that this could be achieved in cavities, in which quantum wells with a large exciton binding energy are embedded, such as in GaN-based cavities. The effects induced by a two-dimensional electron gas on the interaction between the electromagnetic field and the excitons in a semiconductor microcavity are discussed by Cohen et al, who show that the presence of the electron gas is responsible for an efficient interaction between electrons and polaritons. The modification of the optical mode spectrum in microcavities, by introducing lateral photon confinement, is demonstrated by Bayer and collaborators, who show the possibility of tailoring elastic polariton pair-scattering and a suppression of the spontaneous emission for quantum dots embedded in such cavities. The optical properties of biexcitons in microcavities are reviewed by Langbein et al, who perform a detailed investigation of the polariton-biexciton transition and study the biexciton binding energy and dephasing in a microcavity at low temperature. A detailed experimental study of linear and circular polarization dynamics in secondary emission of microcavities in the strong coupling regime is presented by Amand's group, who show that it is possible to manipulate the polariton spin and

Optical methods for microstructure determination of doped samples

Science.gov (United States)

Ciosek, Jerzy F.

2008-12-01

The optical methods to determine refractive index profile of layered materials are commonly used with spectroscopic ellipsometry or transmittance/reflectance spectrometry. Measurements of spectral reflection and transmission usually permit to characterize optical materials and determine their refractive index. However, it is possible to characterize of samples with dopants, impurities as well as defects using optical methods. Microstructures of a hydrogenated crystalline Si wafer and a layer of SiO2 - ZrO2 composition are investigated. The first sample is a Si(001):H Czochralski grown single crystalline wafer with 50 nm thick surface Si02 layer. Hydrogen dose implantation (D continue to be an important issue in microelectronic device and sensor fabrication. Hydrogen-implanted silicon (Si: H) has become a topic of remarkable interest, mostly because of the potential of implantation-induced platelets and micro-cavities for the creation of gettering -active areas and for Si layer splitting. Oxygen precipitation and atmospheric impurity are analysed. The second sample is the layer of co-evaporated SiO2 and ZrO2 materials using simultaneously two electron beam guns in reactive evaporation methods. The composition structure was investigated by X-Ray photoelectron spectroscopy (XPS), and spectroscopic ellipsometry methods. A non-uniformity and composition of layer are analysed using average density method.

Electronic band structures and optical properties of type-II superlattice photodetectors with interfacial effect.

Science.gov (United States)

Qiao, Peng-Fei; Mou, Shin; Chuang, Shun Lien

2012-01-30

The electronic band structures and optical properties of type-II superlattice (T2SL) photodetectors in the mid-infrared (IR) range are investigated. We formulate a rigorous band structure model using the 8-band k · p method to include the conduction and valence band mixing. After solving the 8 × 8 Hamiltonian and deriving explicitly the new momentum matrix elements in terms of envelope functions, optical transition rates are obtained through the Fermi's golden rule under various doping and injection conditions. Optical measurements on T2SL photodetectors are compared with our model and show good agreement. Our modeling results of quantum structures connect directly to the device-level design and simulation. The predicted doping effect is readily applicable to the optimization of photodetectors. We further include interfacial (IF) layers to study the significance of their effect. Optical properties of T2SLs are expected to have a large tunable range by controlling the thickness and material composition of the IF layers. Our model provides an efficient tool for the designs of novel photodetectors.

Optical investigations and control of spindynamics in Mn doped II-VI quantum dots; Optische Untersuchung und Kontrolle der Spindynamik in Mn dotierten II-VI Quantenpunkten

Energy Technology Data Exchange (ETDEWEB)

Schmidt, Thomas

2009-05-13

The present thesis deals with the spin of charge carriers confined in CdSe/ZnSe quantum dots (QDs) closely linked to the polarization of emitted photons. II-VI material systems can be adequately mixed with the B-group element manganese. Such semimagnetic nanostructures offer a number of characteristic optical and electronic features. This is caused by an exchange interaction between the spin of optically excited carriers and the 3d electrons of the Mn ions. Within the framework of this thesis addressing of well defined spin states was realized by optical excitation of charge carriers. The occupation of different spin states was detected by the degree of polarization of the emitted photoluminescence (PL) light. For that purpose different optical methods of time-resolved and time-integrated spectroscopy as well as investigations in magnetic fields were applied. (orig.)

Transferring diffractive optics from research to commercial applications: Part II - size estimations for selected markets

Science.gov (United States)

Brunner, Robert

2014-04-01

In a series of two contributions, decisive business-related aspects of the current process status to transfer research results on diffractive optical elements (DOEs) into commercial solutions are discussed. In part I, the focus was on the patent landscape. Here, in part II, market estimations concerning DOEs for selected applications are presented, comprising classical spectroscopic gratings, security features on banknotes, DOEs for high-end applications, e.g., for the semiconductor manufacturing market and diffractive intra-ocular lenses. The derived market sizes are referred to the optical elements, itself, rather than to the enabled instruments. The estimated market volumes are mainly addressed to scientifically and technologically oriented optical engineers to serve as a rough classification of the commercial dimensions of DOEs in the different market segments and do not claim to be exhaustive.

Comparative Study of Optical and RF Communication Systems for a Mars Mission - Part II. Unified Value Metrics

Science.gov (United States)

Hemmati, H.; Layland, J.; Lesh, J.; Wilson, K.; Sue, M.; Rascoe, D.; Lansing, F.; Wilhelm, M.; Harcke, L.; Chen, C.;

Synthesis, crystal structure, spectroscopic characterization and nonlinear optical properties of Co(II)- picolinate complex

Energy Technology Data Exchange (ETDEWEB)

Tamer, Ömer, E-mail: omertamer@sakarya.edu.tr; Avcı, Davut; Atalay, Yusuf

2015-11-15

A cobalt(II) complex of picolinate was synthesized, and its structure was fully characterized by the applying of X-ray diffraction method as well as FT-IR, FT-Raman and UV–vis spectroscopies. In order to both support the experimental results and convert study to more advanced level, density functional theory calculations were performed by using B3LYP level. Single crystal X-ray structural analysis shows that cobalt(II) ion was located to the center of distorted octahedral geometry. The C=O, C=C and C=N stretching vibrations were found as highly active and strong peaks, inducing the molecular charge transfer within Co(II) complex. The small energy gap between frontier molecular orbital energies was another indicator of molecular charge transfer interactions within Co(II) complex. The nonlinear optical properties of Co(II) complex were investigated at DFT/B3LYP level, and the hypepolarizability parameter was found to be decreased due to the presence of inversion symmetry. The natural bond orbital (NBO) analysis was performed to investigate molecular stability, hyperconjugative interactions, intramolecular charge transfer (ICT) and bond strength for Co(II) complex. Finally, molecular electrostatic potential (MEP) and spin density distributions for Co(II) complex were evaluated. - Highlights: • Co(II) complex of picolinate was prepared. • Its FT-IR, FT-Raman and UV–vis spectra were measured. • DFT calculations were performed to support experimental results. • Small HOMO-LUMO energy gap is an indicator of molecular charge transfer. • Spin density localized on Co(II) as well as O and N atoms.

Optimal Design of an Hourglass in-Fiber Air Fabry-Perot Microcavity—Towards Spectral Characteristics and Strain Sensing Technology

Directory of Open Access Journals (Sweden)

Qi Wang

2017-06-01

Full Text Available An hourglass in-fiber air microcavity Fabry-Perot interferometer is proposed in this paper, and its second reflecting surface of in-fiber microcavity is designed to be a concave reflector with the best curvature radius in order to improve the spectral characteristics. Experimental results proved that the extinction ratio of Fabry-Perot interferometer with cavity length of 60 μm and concave reflector radius of 60 μm is higher than for a rectangular Fabry-Perot interferometer with cavity length of 60 μm (14 dB: 11 dB. Theory and numerical simulation results show that the strain sensitivity of sensor can be improved by reducing the microcavity wall thickness and microcavity diameter, and when the in-fiber microcavity length is 40 μm, the microcavity wall thickness is 10 μm, the microcavity diameter is 20 μm, and the curvature radius of reflective surface II is 50 μm, the interference fringe contrast of is greater than 0.97, an Axial-pull sensitivity of 20.46 nm/N and resolution of 1 mN can be achieved in the range of 0–1 N axial tension. The results show that the performance of hourglass in-fiber microcavity interferometer is far superior to that of the traditional Fabry-Perot interferometer.

Development of the automated circulating tumor cell recovery system with microcavity array.

Science.gov (United States)

Negishi, Ryo; Hosokawa, Masahito; Nakamura, Seita; Kanbara, Hisashige; Kanetomo, Masafumi; Kikuhara, Yoshihito; Tanaka, Tsuyoshi; Matsunaga, Tadashi; Yoshino, Tomoko

2015-05-15

Circulating tumor cells (CTCs) are well recognized as useful biomarker for cancer diagnosis and potential target of drug discovery for metastatic cancer. Efficient and precise recovery of extremely low concentrations of CTCs from blood has been required to increase the detection sensitivity. Here, an automated system equipped with a microcavity array (MCA) was demonstrated for highly efficient and reproducible CTC recovery. The use of MCA allows selective recovery of cancer cells from whole blood on the basis of differences in size between tumor and blood cells. Intra- and inter-assays revealed that the automated system achieved high efficiency and reproducibility equal to the assay manually performed by well-trained operator. Under optimized assay workflow, the automated system allows efficient and precise cell recovery for non-small cell lung cancer cells spiked in whole blood. The automated CTC recovery system will contribute to high-throughput analysis in the further clinical studies on large cohort of cancer patients. Copyright © 2014 Elsevier B.V. All rights reserved.

Near-infrared exciton-polaritons in strongly coupled single-walled carbon nanotube microcavities

Science.gov (United States)

Graf, Arko; Tropf, Laura; Zakharko, Yuriy; Zaumseil, Jana; Gather, Malte C.

2016-10-01

Exciton-polaritons form upon strong coupling between electronic excitations of a material and photonic states of a surrounding microcavity. In organic semiconductors the special nature of excited states leads to particularly strong coupling and facilitates condensation of exciton-polaritons at room temperature, which may lead to electrically pumped organic polariton lasers. However, charge carrier mobility and photo-stability in currently used materials is limited and exciton-polariton emission so far has been restricted to visible wavelengths. Here, we demonstrate strong light-matter coupling in the near infrared using single-walled carbon nanotubes (SWCNTs) in a polymer matrix and a planar metal-clad cavity. By exploiting the exceptional oscillator strength and sharp excitonic transition of (6,5) SWCNTs, we achieve large Rabi splitting (>110 meV), efficient polariton relaxation and narrow band emission (<15 meV). Given their high charge carrier mobility and excellent photostability, SWCNTs represent a promising new avenue towards practical exciton-polariton devices operating at telecommunication wavelengths.

Flatland optics. II. Basic experiments.

Science.gov (United States)

Lohmann, A W; Wang, D; Pe'er, A; Friesem, A A

2001-05-01

In "Flatland optics: fundamentals" [J. Opt. Soc. Am. A 17, 1755 (2000)] we described the basic principles of two-dimensional (2D) optics and showed that a wavelength lambda in three-dimensional (3D) space (x,y,z) may appear in Flatland (x,z) as a wave with another wavelength, lambda = lambda/cosalpha. The tilt angle alpha can be modified by a 3D (Spaceland) individual who then is able to influence the 2D optics in a way that must appear to be magical to 2D Flatland individuals-in the spirit of E. A. Abbott's science fiction story [Flatland, a Romance of Many Dimensions, 6th ed. (Dover, New York, 1952)] of 1884. We now want to establish the reality or objectivity of the 2D wavelength lambda by some basic experiments similar to those that demonstrated roughly 200 years ago the wave nature of light. Specifically, we describe how to measure the 2D wavelength lambda by mean of five different arrangements that involve Young's biprism configuration, Talbot's self-imaging effect, measuring the focal length of a Fresnel zone plate, and letting light be diffracted by a double slit and by a grating. We also performed experiments with most of these arrangements. The results reveal that the theoretical wavelength, as predicted by our Flatland optics theory, does indeed coincide with the wavelength lambda as measured by Flatland experiments. Finally, we present an alternative way to understand Flatland optics in the spatial frequency domains of Flatland and Spaceland.

Highly efficient phosphor-converted white organic light-emitting diodes with moderate microcavity and light-recycling filters.

Science.gov (United States)

Cho, Sang-Hwan; Oh, Jeong Rok; Park, Hoo Keun; Kim, Hyoung Kun; Lee, Yong-Hee; Lee, Jae-Gab; Do, Young Rag

2010-01-18

We demonstrate the combined effects of a microcavity structure and light-recycling filters (LRFs) on the forward electrical efficiency of phosphor-converted white organic light-emitting diodes (pc-WOLEDs). The introduction of a single pair of low- and high-index layers (SiO(2)/TiO(2)) improves the blue emission from blue OLED and the insertion of blue-passing and yellow-reflecting LRFs enhances the forward yellow emission from the YAG:Ce(3+) phosphors layers. The enhancement of the luminous efficacy of the forward white emission is 1.92 times that of a conventional pc-WOLED with color coordinates of (0.34, 0.34) and a correlated color temperature of about 4800 K.

Local Intensity Enhancements in Spherical Microcavities: Implications for Photonic Chemical and Biological Sensors

Science.gov (United States)

Fuller, Kirk A.

2005-01-01

In this report, we summarize recent findings regarding the use spherical microcavities in the amplification of light that is inelastically scattered by either fluorescent or Raman-active molecules. This discussion will focus on Raman scattering, with the understanding that analogous processes apply to fluorescence. Raman spectra can be generated through the use of a very strong light source that stimulates inelastic light scattering by molecules, with the scattering occurring at wavelengths shifted from that of the source and being most prominent at shifts associated with the molecules natural vibrational frequencies. The Raman signal can be greatly enhanced by exposing a molecule to the intense electric fields that arise near surfaces (typically of gold or silver) exhibiting nanoscale roughness. This is known as surface-enhanced Raman scattering (SERS). SERS typically produces gain factors of 103 - 106, but under special conditions, factors of 1010 - 1014 have been achieved.

Numerical modeling of exciton-polariton Bose-Einstein condensate in a microcavity

Science.gov (United States)

Voronych, Oksana; Buraczewski, Adam; Matuszewski, Michał; Stobińska, Magdalena

2017-06-01

A novel, optimized numerical method of modeling of an exciton-polariton superfluid in a semiconductor microcavity was proposed. Exciton-polaritons are spin-carrying quasiparticles formed from photons strongly coupled to excitons. They possess unique properties, interesting from the point of view of fundamental research as well as numerous potential applications. However, their numerical modeling is challenging due to the structure of nonlinear differential equations describing their evolution. In this paper, we propose to solve the equations with a modified Runge-Kutta method of 4th order, further optimized for efficient computations. The algorithms were implemented in form of C++ programs fitted for parallel environments and utilizing vector instructions. The programs form the EPCGP suite which has been used for theoretical investigation of exciton-polaritons. Catalogue identifier: AFBQ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AFBQ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: BSD-3 No. of lines in distributed program, including test data, etc.: 2157 No. of bytes in distributed program, including test data, etc.: 498994 Distribution format: tar.gz Programming language: C++ with OpenMP extensions (main numerical program), Python (helper scripts). Computer: Modern PC (tested on AMD and Intel processors), HP BL2x220. Operating system: Unix/Linux and Windows. Has the code been vectorized or parallelized?: Yes (OpenMP) RAM: 200 MB for single run Classification: 7, 7.7. Nature of problem: An exciton-polariton superfluid is a novel, interesting physical system allowing investigation of high temperature Bose-Einstein condensation of exciton-polaritons-quasiparticles carrying spin. They have brought a lot of attention due to their unique properties and potential applications in polariton-based optoelectronic integrated circuits. This is an out-of-equilibrium quantum system confined

The development of MOSA-II multichannel optical spectrum analyzer

International Nuclear Information System (INIS)

Guo Li; Yang Zhoujing; Fang Shuyao

1989-01-01

The MOSA-II Multichannel Optical Spectrum Analyzer is a high-perfor mance, easy-to-use measurment system for extremely rapid spectral data acquistion, processing and presentation. It consists of four parts: vidicon, data acquiring and timing circuit, the correcting circuit for the geometric distortion and the non-uniform distortion of the vidicon, IBMPC/XT and color plotter. The system has the following functions: single spectrum acquisition, continuous acquisition of multi-spectra, noise reduction, math, operations (including addition, subtraction, multiplication, and division) and geometric transform action of the spectra, and 3D-presentation of the spectra on both the color screen and the plotter. The absolute sensitivity of the system is 18 Photons/sec · mm 2 . The access time for data acquisition is 64 μs/per channel and the spectrum range is 1800 A - 8000A, the geometric distortion<2%, the amplitude error<5%

Elaboration and optical properties of type-II ZnTe on ZnSe heterostructures

Energy Technology Data Exchange (ETDEWEB)

Najjar, Rita, E-mail: rita.najjar@cea.f [CEA-CNRS group ' Nanophysique et semiconducteurs' , Institut NEEL-CNRS, BP166, 25 rue des martyrs, 38042 Grenoble Cedex 9 (France); Andre, Regis; Besombes, Lucien; Bougerol, Catherine; Tatarenko, Serge; Mariette, Henri [CEA-CNRS group ' Nanophysique et semiconducteurs' , Institut NEEL-CNRS, BP166, 25 rue des martyrs, 38042 Grenoble Cedex 9 (France)

2009-11-25

Special growth conditions are presented in this work, in order to produce ZnTe/ZnSe type-II quantum dots and preserve them during the capping stage. A detailed study emphasizes the high sensitivity of the sample structure to Se/Zn ratio as opposed to other growth parameters. It is shown that nominally identical samples can evolve into two-dimensional quantum well or quantum dot plane, depending on which element is in excess. Transmission electron microscopy, atomic force microscopy and optical characterizations evidence this phenomenon.

Metal Nanoparticles/Porous Silicon Microcavity Enhanced Surface Plasmon Resonance Fluorescence for the Detection of DNA

Directory of Open Access Journals (Sweden)

Jiajia Wang

2018-02-01

Full Text Available A porous silicon microcavity (PSiMC with resonant peak wavelength of 635 nm was fabricated by electrochemical etching. Metal nanoparticles (NPs/PSiMC enhanced fluorescence substrates were prepared by the electrostatic adherence of Au NPs that were distributed in PSiMC. The Au NPs/PSiMC device was used to characterize the target DNA immobilization and hybridization with its complementary DNA sequences marked with Rhodamine red (RRA. Fluorescence enhancement was observed on the Au NPs/PSiMC device substrate; and the minimum detection concentration of DNA ran up to 10 pM. The surface plasmon resonance (SPR of the MC substrate; which is so well-positioned to improve fluorescence enhancement rather the fluorescence enhancement of the high reflection band of the Bragg reflector; would welcome such a highly sensitive in biosensor.

Metal Nanoparticles/Porous Silicon Microcavity Enhanced Surface Plasmon Resonance Fluorescence for the Detection of DNA.

Science.gov (United States)

Wang, Jiajia; Jia, Zhenhong

2018-02-23

A porous silicon microcavity (PSiMC) with resonant peak wavelength of 635 nm was fabricated by electrochemical etching. Metal nanoparticles (NPs)/PSiMC enhanced fluorescence substrates were prepared by the electrostatic adherence of Au NPs that were distributed in PSiMC. The Au NPs/PSiMC device was used to characterize the target DNA immobilization and hybridization with its complementary DNA sequences marked with Rhodamine red (RRA). Fluorescence enhancement was observed on the Au NPs/PSiMC device substrate; and the minimum detection concentration of DNA ran up to 10 pM. The surface plasmon resonance (SPR) of the MC substrate; which is so well-positioned to improve fluorescence enhancement rather the fluorescence enhancement of the high reflection band of the Bragg reflector; would welcome such a highly sensitive in biosensor.

Spectrum study of top-emitting organic light-emitting devices with micro-cavity structure

International Nuclear Information System (INIS)

Liu Xiang; Wei Fuxiang; Liu Hui

2009-01-01

Blue and white top-emitting organic light-emitting devices OLEDs with cavity effect have been fabricated. TBADN:3%DSAPh and Alq 3 :DCJTB/TBADN:TBPe/Alq 3 :C545 were used as emitting materials of microcavity OLEDs. On a patterned glass substrate, silver was deposited as reflective anode, and copper phthalocyanine (CuPc) layer as HIL and 4'-bis[N-(1-Naphthyl)- N-phenyl-amino]biphenyl (NPB) layer as HTL were made. Al/Ag thin films were made as semi-transparent cathode with a transmittance of about 30%. By changing the thickness of indium tin oxide ITO, deep blue with Commission Internationale de L'Eclairage chromaticity coordinates (CIEx, y) of (0.141, 0.049) was obtained on TBADN:3%DSAPh devices, and different color (red, blue and green) was obtained on Alq 3 :DCJTB/TBADN:TBPe/Alq 3 :C545 devices, full width at half maxima (FWHM) was only 17 nm. The spectral intensity and FWHM of emission in cavity devices have also been studied.

Biochemical component identification by plasmonic improved whispering gallery mode optical resonance based sensor

Science.gov (United States)

Saetchnikov, Vladimir A.; Tcherniavskaia, Elina A.; Saetchnikov, Anton V.; Schweiger, Gustav; Ostendorf, Andreas

2014-05-01

Experimental data on detection and identification of variety of biochemical agents, such as proteins, microelements, antibiotic of different generation etc. in both single and multi component solutions under varied in wide range concentration analyzed on the light scattering parameters of whispering gallery mode optical resonance based sensor are represented. Multiplexing on parameters and components has been realized using developed fluidic sensor cell with fixed in adhesive layer dielectric microspheres and data processing. Biochemical component identification has been performed by developed network analysis techniques. Developed approach is demonstrated to be applicable both for single agent and for multi component biochemical analysis. Novel technique based on optical resonance on microring structures, plasmon resonance and identification tools has been developed. To improve a sensitivity of microring structures microspheres fixed by adhesive had been treated previously by gold nanoparticle solution. Another technique used thin film gold layers deposited on the substrate below adhesive. Both biomolecule and nanoparticle injections caused considerable changes of optical resonance spectra. Plasmonic gold layers under optimized thickness also improve parameters of optical resonance spectra. Biochemical component identification has been also performed by developed network analysis techniques both for single and for multi component solution. So advantages of plasmon enhancing optical microcavity resonance with multiparameter identification tools is used for development of a new platform for ultra sensitive label-free biomedical sensor.

Bistable Topological Insulator with Exciton-Polaritons

Science.gov (United States)

Kartashov, Yaroslav V.; Skryabin, Dmitry V.

2017-12-01

The functionality of many nonlinear and quantum optical devices relies on the effect of optical bistability. Using microcavity exciton-polaritons in a honeycomb arrangement of microcavity pillars, we report the resonance response and bistability of topological edge states. A balance between the pump, loss, and nonlinearity ensures a broad range of dynamical stability and controls the distribution of power between counterpropagating states on the opposite edges of the honeycomb lattice stripe. Tuning energy and polarization of the pump photons, while keeping their momentum constant, we demonstrate control of the propagation direction of the dominant edge state. Our results facilitate the development of practical applications of topological photonics.

Bragg polaritons in a ZnSe-based unfolded microcavity at elevated temperatures

Energy Technology Data Exchange (ETDEWEB)

Sebald, K.; Rahman, SK. S.; Cornelius, M.; Kaya, T.; Gutowski, J. [Semiconductor Optics, Institute of Solid State Physics, University of Bremen, 28334 Bremen (Germany); Klein, T.; Gust, A.; Hommel, D. [Semiconductor Epitaxy, Institute of Solid State Physics, University of Bremen, 28334 Bremen (Germany); Klembt, S. [Institut Néel, Université Grenoble Alpes and CNRS, B.P. 166, 38042 Grenoble (France)

2016-03-21

In this contribution, we present strong coupling of ZnSe quantum well excitons to Bragg modes resulting in the formation of Bragg polariton eigenstates, characterized by a small effective mass in comparison to a conventional microcavity. We observe an anticrossing of the excitonic and the photonic component in our sample being a clear signature for the strong-coupling regime. The anticrossing is investigated by changing the detuning between the excitonic components and the Bragg mode. We find anticrossings between the first Bragg mode and the heavy- as well as light-hole exciton, respectively, resulting in three polariton branches. The observed Bragg-polariton branches are in good agreement with theoretical calculations. The strong indication for the existence of strong coupling is traceable up to a temperature of 200 K, with a Rabi-splitting energy of 24 meV and 13 meV for the Bragg mode with the heavy- and light-hole exciton, respectively. These findings demonstrate the advantages of this sample configuration for ZnSe-based devices for the strong coupling regime.

Precision PEP-II optics measurement with an SVD-enhanced Least-Square fitting

Science.gov (United States)

Yan, Y. T.; Cai, Y.

2006-03-01

A singular value decomposition (SVD)-enhanced Least-Square fitting technique is discussed. By automatic identifying, ordering, and selecting dominant SVD modes of the derivative matrix that responds to the variations of the variables, the converging process of the Least-Square fitting is significantly enhanced. Thus the fitting speed can be fast enough for a fairly large system. This technique has been successfully applied to precision PEP-II optics measurement in which we determine all quadrupole strengths (both normal and skew components) and sextupole feed-downs as well as all BPM gains and BPM cross-plane couplings through Least-Square fitting of the phase advances and the Local Green's functions as well as the coupling ellipses among BPMs. The local Green's functions are specified by 4 local transfer matrix components R12, R34, R32, R14. These measurable quantities (the Green's functions, the phase advances and the coupling ellipse tilt angles and axis ratios) are obtained by analyzing turn-by-turn Beam Position Monitor (BPM) data with a high-resolution model-independent analysis (MIA). Once all of the quadrupoles and sextupole feed-downs are determined, we obtain a computer virtual accelerator which matches the real accelerator in linear optics. Thus, beta functions, linear coupling parameters, and interaction point (IP) optics characteristics can be measured and displayed.

Feasibility of Optical Instruments Based on Multiaperture Optics.

Science.gov (United States)

1984-10-16

system may be configured. The optical elements may be nonimaging concentrators (light horns), the field of view (FOV) of which may be controlled by a...RD-RI58 868 FEASIBILITY OF OPTICAL INSTRUMENTS BASED ON i/I MULTIAPERTURE OPTICS (U) FLORIDA UNIV GAINESVILLE DEPT OF NUCLEAR ENGINEERING SCIENCES J D...d Subtitle) 5. TYPE OF REPORT & PERIOD COVERED ’ 0 Feasibility of Optical Instruments Based on Final Report * CD Multiaperature Optics 615/83 to 9/30

Pulse reshaping in photonic crystal waveguides and microcavities with Kerr nonlinearity: Critical issues for all-optical switching

International Nuclear Information System (INIS)

Vujic, Dragan; John, Sajeev

2005-01-01

We delineate critical issues for 'controlling light with light' in photonic crystal (PC) waveguides coupled to Kerr-nonlinear microresonators. These arise from (a) fundamental trade-off between switching speed and switching intensity threshold inherent in high-quality Q-factor cavities and (b) the dynamical nonlinear oscillation of such cavities in response to incident light pulses. Using finite-difference time-domain simulations of electromagnetic pulse propagation, we consider both (i) a nonlinear Fabry-Perot microresonator (embedded within a PC waveguide) exhibiting a narrow transmission resonance and (ii) a nonlinear point defect (side-coupled to a PC waveguide) exhibiting a narrow reflection spectrum. We describe self-induced switching from transmission to reflection induced by pulse intensity tuning as well as control of pulse transmission induced by the secondary, continuous (cw) laser field propagating through the same PC waveguide. For the Fabry-Perot microresonator, a well-defined self-switching threshold is obtained. However, this is accompanied by considerable temporal and spectral distortion of the pulse caused by the oscillatory nonlinear response of the microresonator. When the quality factor of the microresonator is increased, the switching intensity threshold can be lowered but the pulse transit (switching) time and the pulse distortion are increased. For the side-coupled microresonator, a gradual (not sharp) self-switching behavior as a function of incident intensity is obtained. For both the Fabry-Perot and side-coupled nonlinear microresonators, control of pulse transmission can be achieved by means of a secondary cw laser field. The cw power required for switching with realistic Kerr nonlinearities is in excess of 1 W/μm 2 and may cause optical damage to the semiconducting PC backbone. Both instantaneous and noninstantaneous Kerr-response models are considered. Our results underscore the limitations and trade-offs inherent in the possible

MONSTIR II: A 32-channel, multispectral, time-resolved optical tomography system for neonatal brain imaging

Energy Technology Data Exchange (ETDEWEB)

Cooper, Robert J., E-mail: robert.cooper@ucl.ac.uk; Magee, Elliott; Everdell, Nick; Magazov, Salavat; Varela, Marta; Airantzis, Dimitrios; Gibson, Adam P.; Hebden, Jeremy C. [Biomedical Optics Research Laboratory, Department of Medical Physics and Bioengineering, University College London, London WC1E 6BT (United Kingdom)

2014-05-15

We detail the design, construction and performance of the second generation UCL time-resolved optical tomography system, known as MONSTIR II. Intended primarily for the study of the newborn brain, the system employs 32 source fibres that sequentially transmit picosecond pulses of light at any four wavelengths between 650 and 900 nm. The 32 detector channels each contain an independent photo-multiplier tube and temporally correlated photon-counting electronics that allow the photon transit time between each source and each detector position to be measured with high temporal resolution. The system's response time, temporal stability, cross-talk, and spectral characteristics are reported. The efficacy of MONSTIR II is demonstrated by performing multi-spectral imaging of a simple phantom.

Optical RISC computer

Science.gov (United States)

Guilfoyle, Peter S.; Stone, Richard V.; Hessenbruch, John M.; Zeise, Frederick F.

1993-07-01

A second generation digital optical computer (DOC II) has been developed which utilizes a RISC based operating system as its host. This 32 bit, high performance (12.8 GByte/sec), computing platform demonstrates a number of basic principals that are inherent to parallel free space optical interconnects such as speed (up to 1012 bit operations per second) and low power 1.2 fJ per bit). Although DOC II is a general purpose machine, special purpose applications have been developed and are currently being evaluated on the optical platform.

Physical optics

International Nuclear Information System (INIS)

Kim Il Gon; Lee, Seong Su; Jang, Gi Wan

2012-07-01

This book indicates physical optics with properties and transmission of light, mathematical expression of wave like harmonic wave and cylindrical wave, electromagnetic theory and light, transmission of light with Fermat principle and Fresnel equation, geometrical optics I, geometrical optics II, optical instrument such as stops, glasses and camera, polarized light like double refraction by polarized light, interference, interference by multiple reflections, diffraction, solid optics, crystal optics such as Faraday rotation and Kerr effect and measurement of light. Each chapter has an exercise.

Physical optics

Energy Technology Data Exchange (ETDEWEB)

Kim Il Gon; Lee, Seong Su; Jang, Gi Wan

2012-07-15

This book indicates physical optics with properties and transmission of light, mathematical expression of wave like harmonic wave and cylindrical wave, electromagnetic theory and light, transmission of light with Fermat principle and Fresnel equation, geometrical optics I, geometrical optics II, optical instrument such as stops, glasses and camera, polarized light like double refraction by polarized light, interference, interference by multiple reflections, diffraction, solid optics, crystal optics such as Faraday rotation and Kerr effect and measurement of light. Each chapter has an exercise.

Advanced Design of the First Quasi-optical Transmission Line for ECRH at TJ-II

International Nuclear Information System (INIS)

Fernandez, A.; Likin, K.; Martin, R.

1999-01-01

TJ-II plasma start-up and heating are made by electron cyclotron resonance waves at the second harmonic of the electron cyclotron frequency. The microwave power of the gyrotrons is transmitted by two quasi-optical transmission lines. The first line launches the microwave power under fixed injection geometry, i. e. there is no a possibility to change the launching angle the wave polarization. Due to the long distance between the last focusing mirror and the center TJ-II vessel the beam is quite wide at plasma border. The second line has a moveable mirror installed inside the TJ-II vessel. To get high absorption efficiency and a narrow energy deposition profile the internal mirror focuses the wave beam at plasma center. The beam width is about 2 cm. To get more flexibility in experiments on heating and current drive the first transmission line needs to be upgraded. The designs is presented in this report. It includes and internal mirror to focus the beam and to change the injection angle. A polarizer consisting in two corrugated mirrors will be incorporated to get any wave polarization. Two mirrors with an array of coupling holes and calorimetric measurements of the energy absorbed in the barrier window will permit the estimation of the microwave power launched the TJ-II. (Author) 13 refs

Cooperative spontaneous emission of nano-emitters with inter-emitter coupling in a leaky microcavity

International Nuclear Information System (INIS)

Hong, Suc-Kyoung; Nam, Seog Woo; Yang, Hyung Jin

2015-01-01

We study the spontaneous emission from a few two-level nano-emitters placed in a leaky microcavity with Lorentzian spectral density near a critically damped regime. Collective features of the spontaneous emission are investigated by numerical analysis of the excitation dynamics when initially one nano-emitter is totally excited but we do not know which one. The results show that there are three decay rates in the excitation dynamics, two for simple exponential decays and one for damped oscillatory decay. The excitation dynamics is found to critically depend on the regime of the system. It is shown that the spontaneous emission is enhanced or suppressed depending on whether the system is in the underdamped or overdamped regime, respectively. On the other hand, the cooperative spontaneous emission is suppressed in the underdamped while it is enhanced in the overdamped regime. Furthermore, the effect of the direct inter-emitter coupling on the breaking of the cooperativeness of the spontaneous emission is shown as well. (paper)

Study of Transitions between Wetting States on Microcavity Arrays by Optical Transmission Microscopy

DEFF Research Database (Denmark)

Søgaard, Emil; Andersen, Nis Korsgaard; Smistrup, Kristian

2014-01-01

In this article, we present a simple and fast optical method based on transmission microscopy to study the stochastic wetting transitions on micro- and nanostructured polymer surfaces immersed in water. We analyze the influence of immersion time and the liquid pressure on the degree of water......-Laplace equation for the water menisci in the cavities and the diffusion of dissolved gas molecules in the water. In addition, the wetting transitions had a stochastic nature, which resulted from the short diffusion distance for dissolved gas molecules in the water between neighboring cavities. Furthermore, we...... compared the contact angle properties of two polymeric materials (COC and PP) with moderate hydrophobicity. We attributed the difference in the water repellency of the two materials to a difference in the wetting of their nanostructures. Our experimental observations thus indicate that both the diffusion...

Amalgamation based optical and colorimetric sensing of mercury(II) ions with silver graphene oxide nanocomposite materials

International Nuclear Information System (INIS)

Kamali, Khosro Zangeneh; Pandikumar, Alagarsamy; Jayabal, Subramaniam; Huang, Nay Ming; Ramaraj, Ramasamy; Lim, Hong Ngee; Ong, Boon Hoong; Bien, Chia Sheng Daniel; Kee, Yeh Yee

2016-01-01

The article describes a facile method for the preparation of a conjugate composed of silver nanoparticles and graphene oxide (Ag GO) via chemical reduction of silver precursors in the presence of graphene oxide (GO) while sonicating the solution. The Ag GO was characterized by X-ray photoelectron spectroscopy, X-ray powder diffraction, and energy-dispersive X-ray spectroscopy. The nanocomposite undergoes a color change from yellow to colorless in presence of Hg(II), and this effect is based on the disappearance of the localized surface plasmon resonance absorption of the AgNPs due to the formation of silver-mercury amalgam. The presence of GO, on the other hand, prevents the agglomeration of the AgNPs and enhances the stability of the nanocomposite material in solution. Hence, the probe represents a viable optical probe for the determination of mercury(II) ions in that it can be used to visually detect Hg(II) concentrations as low as 100 μM. The instrumental LOD is 338 nM. (author)

Note: Optical fiber milled by focused ion beam and its application for Fabry-Pérot refractive index sensor

DEFF Research Database (Denmark)

Yuan, Scott Wu; Wang, Fei; Savenko, Alexey

2011-01-01

We introduce a highly compact fiber-optic Fabry-Pérot refractive index sensor integrated with a fluid channel that is fabricated directly near the tip of a 32 μm in diameter single-mode fiber taper. The focused ion beam technique is used to efficiently mill the microcavity from the fiber side...... and finely polish the end facets of the cavity with a high spatial resolution. It is found that a fringe visibility of over 15 dB can be achieved and that the sensor has a sensitivity of ∼1731 nm/RIU (refractive index units) and a detection limit of ∼5.78 × 10−6 RIU. This miniature integrated all-in-fiber...

Enhancement of Faraday rotation at photonic-band-gap edge in garnet-based magnetophotonic crystals

International Nuclear Information System (INIS)

Zhdanov, A.G.; Fedyanin, A.A.; Aktsipetrov, O.A.; Kobayashi, D.; Uchida, H.; Inoue, M.

2006-01-01

Spectral dependences of Faraday rotation angle in one-dimensional garnet-based magnetophotonic crystals are considered. The enhancement of Faraday angle is demonstrated at the photonic band gap (PBG) edge both theoretically and experimentally. It is shown to be associated with the optical field localization in the magnetic layers of the structure. The advantages of magnetophotonic crystals in comparison with traditional magnetic microcavities are discussed. The specially designed microcavity structures optimized for the Faraday effect enhancement at the PBG edge are suggested

Magneto-optical observation of twisted vortices in type-II superconductors

Science.gov (United States)

Indenbom, M. V.; van der Beek, C. J.; Berseth, V.; Benoit, W.; D'Anna, G.; Erb, A.; Walker, E.; Flükiger, R.

1997-02-01

When magnetic flux penetrates a type-II superconductor, it does so as quantized flux lines or vortex lines, so called because each is surrounded by a supercurrent vortex. Interactions between such vortices lead to a very rich and well characterized phenomenology for this 'mixed state'. But an outstanding question remains: are individual vortex lines 'strong', or can they easily be cut and made to pass through one another? The concept of vortex cutting was originally proposed to account for dissipation observed in superconducting wires oriented parallel to an applied magnetic field, where the vortex lines and transport current should be in a force-free configuration1-6. Previous experiments, however, have been unable to establish the vortex topology in the force-free configuration or the size of the energy barrier for vortex cutting. Here we report magneto-optical images of YBa2Cu3O7-δ samples in the force-free configuration which show that thousands of vortex lines can twist together to form highly stable structures. In some cases, these 'vortex twisters' interact with one another to produce wave-like dynamics. Our measurements also determine directly the current required to initiate vortex cutting, and show that it is much higher than that needed to overcome the pinning of vortices by material defects. This implies that thermodynamic phases of entangled vortices7-10 are intrinsically stable and may occupy a significant portion of the mixed-state phase diagram for type-II superconductors.

Optical characterization of CdSe/ZnTe type-II interfaces for photovoltaics

Energy Technology Data Exchange (ETDEWEB)

Richters, Jan-Peter; Bleuse, Joel [CEA-CNRS group ' ' Nanophysique et semiconducteurs' ' , CEA-Grenoble, INAC, SP2M, 17 rue des Martyrs, 38042 Grenoble (France); Gerard, Lionel; Andre, Regis [CEA-CNRS group ' ' Nanophysique et semiconducteurs' ' , Institut Neel, CNRS, BP 166, 38042 Grenoble Cedex 9 (France)

2012-07-01

Solar cells based on direct bandgap semiconductors (GaAs,CdTe,CdSe..) show an efficient light absorption compared to silicon solar cells. This is an advantage for material savings due to thinner absorbers, but it also comes with the drawback of higher losses due to efficient radiative electron-hole recombination. Such losses could be prevented through the use of type-II interfaces which separate electrons and holes within the active area, similar to a p-n junction. We report a study of CdSe/ZnTe samples showing such an interface. The CdSe bandgap (1.7 eV) is well adapted to the solar spectrum and its lattice parameter mismatch with ZnTe is exceptionally low. We have grown, by MBE, different kinds of samples like CdSe/ZnTe 2D interfaces and superlattices and present time-resolved spectroscopy results which specify the efficiency of the electron-hole separation in these type-II structures. The measured decay time can be above 100 ns for the interface optical transition, i.e. 3 orders of magnitude slower than the typical PL decay time for the constitutive materials taken separately.

Fiberless Optical Gyroscope, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — We propose a radical new approach for to the design and fabrication of a fiber-less Interferometric Optical Gyroscope (IOG) that enables the production of a...

Quantum optics and nano-optics teaching laboratory for the undergraduate curriculum: teaching quantum mechanics and nano-physics with photon counting instrumentation

Science.gov (United States)

Lukishova, Svetlana G.

2017-08-01

At the Institute of Optics, University of Rochester (UR), we have adapted to the main challenge (the lack of space in the curriculum) by developing a series of modular 3-hour experiments and 20-min-demonstrations based on technical elective, 4-credit-hour laboratory course "Quantum Optics and Nano-Optics Laboratory" (OPT 253/OPT453/PHY434), that were incorporated into a number of required courses ranging from freshman to senior level. Rochester Monroe Community College (MCC) students also benefited from this facility that was supported by four NSF grants. MCC students carried out two 3-hour labs on photon quantum mechanics at the UR. Since 2006, total 566 students passed through the labs with lab reports submission (including 144 MCC students) and more than 250 students through lab demonstrations. In basic class OPT 253, four teaching labs were prepared on generation and characterization of entangled and single (antibunched) photons demonstrating the laws of quantum mechanics: (1) entanglement and Bell's inequalities, (2) single-photon interference (Young's double slit experiment and Mach-Zehnder interferometer), (3) confocal microscope imaging of single-emitter (colloidal nanocrystal quantum dots and NV-center nanodiamonds) fluorescence within photonic (liquid crystal photonic bandgap microcavities) or plasmonic (gold bowtie nanoantennas) nanostructures, (4) Hanbury Brown and Twiss setup. Fluorescence antibunching from nanoemitters. Students also carried out measurements of nanodiamond topography using atomic force microscopy and prepared photonic bandgap materials from cholesteric liquid crystals. Manuals, student reports, presentations, lecture materials and quizzes, as well as some NSF grants' reports are placed on a website http://www.optics.rochester.edu/workgroups/lukishova/QuantumOpticsLab/ . In 2011 UR hosted 6 professors from different US universities in three-days training of these experiments participating in the Immersion Program of the Advanced

The at-wavelength metrology facility for UV- and XUV-reflection and diffraction optics at BESSY-II

Science.gov (United States)

Schäfers, F.; Bischoff, P.; Eggenstein, F.; Erko, A.; Gaupp, A.; Künstner, S.; Mast, M.; Schmidt, J.-S.; Senf, F.; Siewert, F.; Sokolov, A.; Zeschke, Th.

2016-01-01

A technology center for the production of high-precision reflection gratings has been established. Within this project a new optics beamline and a versatile reflectometer for at-wavelength characterization of UV- and XUV-reflection gratings and other (nano-) optical elements has been set up at BESSY-II. The Plane Grating Monochromator beamline operated in collimated light (c-PGM) is equipped with an SX700 monochromator, of which the blazed gratings (600 and 1200 lines mm−1) have been recently exchanged for new ones of improved performance produced in-house. Over the operating range from 10 to 2000 eV this beamline has very high spectral purity achieved by (i) a four-mirror arrangement of different coatings which can be inserted into the beam at different angles and (ii) by absorber filters for high-order suppression. Stray light and scattered radiation is removed efficiently by double sets of in situ exchangeable apertures and slits. By use of in- and off-plane bending-magnet radiation the beamline can be adjusted to either linear or elliptical polarization. One of the main features of a novel 11-axes reflectometer is the possibility to incorporate real life-sized gratings. The samples are adjustable within six degrees of freedom by a newly developed UHV-tripod system carrying a load up to 4 kg, and the reflectivity can be measured between 0 and 90° incidence angle for both s- and p-polarization geometry. This novel powerful metrology facility has gone into operation recently and is now open for external users. First results on optical performance and measurements on multilayer gratings will be presented here. PMID:26698047

Wave function analysis of type-II self-assembled quantum dot structures using magneto-optics

International Nuclear Information System (INIS)

Godoy, Marcio Peron Franco de; Nakaema, Marcelo K.K.; Gomes, Paulo F.; Iikawa, Fernando; Brasil, Maria Jose S.P.; Bortoleto, Jose Roberto R.; Cotta, Monica A.; Ribeiro, Evaldo; Medeiros-Ribeiro, Gilberto; Marques, Gilmar E.; Bittencourt, A.C.R.

2004-01-01

Full text: Recently, self-assembled quantum dots have attracted considerable attention for their potential for device applications. Type II interface, in particular, present interesting properties due to the space separation of the carriers. One of the carriers is confined at the lower band gap layer and the other remains at the barrier layers and is only localized by the Coulomb attraction. An essential information for using type II quantum wells and quantum dots on technological applications is the localization of the carrier wave function, which is an experimentally difficult parameter to be measured. Some techniques have been proposed to map the wave functions in quantum dots such as magneto-tunneling spectroscopy and near- field scanning optical microscopy. These techniques involve however a very complex experimental apparatus and sample processing. The magneto-exciton transition can be used as an alternative tool to investigate the exciton wave function distribution, since this distribution has a strong influence on the diamagnetic shift and Zeeman splitting. In this work, we present magneto-optical studies of In P/GaAs type II self-assembled quantum dots, where the electron is strongly confined at the In P, while the hole is weakly localized at the GaAs barrier due to the Coulombic attraction from the electrons. This scenery is very distinct from type I systems. The weaker hole confinement should alter the valence band mixing resulting in a different valence band contribution on the Zeeman splitting as compared to type I systems. Based on the results of the magneto-exciton emission from the wetting layer and from the individual dots, we obtained interesting results concerning the wave function distribution in our system. We discuss the localization of the hole wave function along the growth direction based on the measured Zeeman splitting and the in-plane wave function distribution, based on the observed diamagnetic shift. A remarkable result is that the

Preparation of a novel pH optical sensor using orange (II) based on agarose membrane as support.

Science.gov (United States)

Heydari, Rouhollah; Hosseini, Mohammad; Amraei, Ahmadreza; Mohammadzadeh, Ali

2016-04-01

A novel and cost effective optical pH sensor was prepared using covalent immobilization of orange (II) indicator on the agarose membrane as solid support. The fabricated optical sensor was fixed into a sample holder of a spectrophotometer instrument for pH monitoring. Variables affecting sensor performance including pH of dye bonding to agarose membrane and dye concentration were optimized. The sensor responds to the pH changes in the range of 3.0-10.0 with a response time of 2.0 min and appropriate reproducibility (RSD ≤ 0.9%). No significant variation was observed on sensor response after increasing the ionic strength in the range of 0.0-0.5M of sodium chloride. Determination of pH using the proposed optical sensor is quick, simple, inexpensive, selective and sensitive in the pH range of 3.0-10.0. Copyright © 2015 Elsevier B.V. All rights reserved.

The CLASS blazar survey - II. Optical properties

NARCIS (Netherlands)

Caccianiga, A; Marcha, MJ; Anton, S; Mack, KH; Neeser, MJ

2002-01-01

This paper presents the optical properties of the objects selected in the CLASS blazar survey. Because an optical spectrum is now available for 70 per cent of the 325 sources present in the sample, a spectral classification, based on the appearance of the emission/absorption lines, is possible. A

Sol-gel based optical sensor for determination of Fe (II): a novel probe for iron speciation.

Science.gov (United States)

Samadi-Maybodi, Abdolraouf; Rezaei, Vida; Rastegarzadeh, Saadat

2015-02-05

A highly selective optical sensor for Fe (II) ions was developed based on entrapment of a sensitive reagent, 2,4,6-tri(2-pyridyl)-s-triazine (TPTZ), in a silica sol-gel thin film coated on a glass substrate. The thin films fabricated based on tetraethoxysilane (TEOS) as precursor, sol-gel pH∼3, water:alkoxyde ratio of 4:1 and TPTZ concentration of 0.112 mol L(-1). The influence of sol-gel parameters on sensing behavior of the fabricated sensor was also investigated. The fabricated sensor can be used for determination of Fe (II) ion with an outstanding high selectivity over a dynamic range of 5-115 ng mL(-1) and a detection limit of 1.68 ng mL(-1). It also showed reproducible results with relative standard deviation of 3.5% and 1.27% for 10 and 90 ng mL(-1) of Fe (II), respectively, along with a fast response time of ∼120 s. Total iron also was determined after reduction of Fe (III) to Fe (II) using ascorbic acid as reducing agent. Then, the concentration of Fe (III) was calculated by subtracting the concentration of Fe (II) from the total iron concentration. Interference studies showed a good selectivity for Fe (II) with trapping TPTZ into sol-gel matrix and appropriately adjusting the structure of doped sol-gel. The sensor was compared with other sensors and was applied to determine iron in different water samples with good results. Copyright © 2014 Elsevier B.V. All rights reserved.

Design considerations for quasi-phase-matching in doubly resonant lithium niobate hexagonal microresonators

CSIR Research Space (South Africa)

Sono, Tleyane J

2017-08-01

Full Text Available Fabrication capabilities of high optical quality hexagonal superstructures by chemical etching of inverted ferroelectric domains in lithium niobate platform suggests a route for efficient implementation of compact hexagonal microcavities...

Mode coupling in hybrid square-rectangular lasers for single mode operation

Energy Technology Data Exchange (ETDEWEB)

Ma, Xiu-Wen; Huang, Yong-Zhen, E-mail: yzhuang@semi.ac.cn; Yang, Yue-De; Xiao, Jin-Long; Weng, Hai-Zhong; Xiao, Zhi-Xiong [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100083 (China)

2016-08-15

Mode coupling between a square microcavity and a Fabry-Pérot (FP) cavity is proposed and demonstrated for realizing single mode lasers. The modulations of the mode Q factor as simulation results are observed and single mode operation is obtained with a side mode suppression ratio of 46 dB and a single mode fiber coupling loss of 3.2 dB for an AlGaInAs/InP hybrid laser as a 300-μm-length and 1.5-μm-wide FP cavity connected to a vertex of a 10-μm-side square microcavity. Furthermore, tunable single mode operation is demonstrated with a continuous wavelength tuning range over 10 nm. The simple hybrid structure may shed light on practical applications of whispering-gallery mode microcavities in large-scale photonic integrated circuits and optical communication and interconnection.

Sirepo: a web-based interface for physical optics simulations - its deployment and use at NSLS-II

Science.gov (United States)

Rakitin, Maksim S.; Chubar, Oleg; Moeller, Paul; Nagler, Robert; Bruhwiler, David L.

2017-08-01

"Sirepo" is an open source cloud-based software framework which provides a convenient and user-friendly web-interface for scientific codes such as Synchrotron Radiation Workshop (SRW) running on a local machine or a remote server side. SRW is a physical optics code allowing to simulate the synchrotron radiation from various insertion devices (undulators and wigglers) and bending magnets. Another feature of SRW is a support of high-accuracy simulation of fully- and partially-coherent radiation propagation through X-ray optical beamlines, facilitated by so-called "Virtual Beamline" module. In the present work, we will discuss the most important features of Sirepo/SRW interface with emphasis on their use for commissioning of beamlines and simulation of experiments at National Synchrotron Light Source II. In particular, "Flux through Finite Aperture" and "Intensity" reports, visualizing results of the corresponding SRW calculations, are being routinely used for commissioning of undulators and X-ray optical elements. Material properties of crystals, compound refractive lenses, and some other optical elements can be dynamically obtained for the desired photon energy from the databases publicly available at Argonne National Lab and at Lawrence Berkeley Lab. In collaboration with the Center for Functional Nanomaterials (CFN) of BNL, a library of samples for coherent scattering experiments has been implemented in SRW and the corresponding Sample optical element was added to Sirepo. Electron microscope images of artificially created nanoscale samples can be uploaded to Sirepo to simulate scattering patterns created by synchrotron radiation in different experimental schemes that can be realized at beamlines.

Biomimetic hairy surfaces as superhydrophobic highly transmissive films for optical applications (Conference Presentation)

Science.gov (United States)

Vuellers, Felix; Gomard, Guillaume; Preinfalk, Jan B.; Klampaftis, Efthymios; Worgull, Matthias; Richards, Bryce S.; Hölscher, Hendrik; Kavalenka, Maryna N.

2017-02-01

Combining high optical transmission, water-repellency and self-cleaning is of great interest for optoelectronic devices operating in outdoor conditions, such as photovoltaics where shading can significantly reduce the power output. The surface of water plant Pistia stratiotes combines these functionalities through a dense layer of transparent microhairs. It renders the surface superhydrophobic without affecting absorption of sunlight necessary for photosynthesis. Inspired by this surface, we fabricated a superhydrophobic flexible thin nanofur film made from optical grade polycarbonate using a scalable combination of hot embossing and hot pulling techniques. During fabrication, heated sandblasted steel plates locally elongate softened polymer, thus covering its surface in microcavities surrounded by high aspect ratio micro- and nanohairs. The superhydrophobic nanofur exhibits contact angles of (166+/-6°), low sliding angles (drops below 4% when coated on a polymeric substrate, which can enhance light extraction in organic light emitting diodes (OLEDs). We report an increase of more than 10% in luminous efficacy for a nanofur coated OLED compared to a bare device. Finally, the nanofur film can be used for enhancing the incoupling of light to solar cells, while additionally providing self-cleaning properties. Optical coupling of the nanofur to a multi-crystalline silicon solar cell results in a 5.8% gain in photocurrent compared to a bare device under normal incidence.

Optical photon transport in powdered-phosphor scintillators. Part II. Calculation of single-scattering transport parameters

Energy Technology Data Exchange (ETDEWEB)

Poludniowski, Gavin G. [Joint Department of Physics, Division of Radiotherapy and Imaging, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT, United Kingdom and Centre for Vision Speech and Signal Processing (CVSSP), Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Evans, Philip M. [Centre for Vision Speech and Signal Processing (CVSSP), Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

2013-04-15

Purpose: Monte Carlo methods based on the Boltzmann transport equation (BTE) have previously been used to model light transport in powdered-phosphor scintillator screens. Physically motivated guesses or, alternatively, the complexities of Mie theory have been used by some authors to provide the necessary inputs of transport parameters. The purpose of Part II of this work is to: (i) validate predictions of modulation transform function (MTF) using the BTE and calculated values of transport parameters, against experimental data published for two Gd{sub 2}O{sub 2}S:Tb screens; (ii) investigate the impact of size-distribution and emission spectrum on Mie predictions of transport parameters; (iii) suggest simpler and novel geometrical optics-based models for these parameters and compare to the predictions of Mie theory. A computer code package called phsphr is made available that allows the MTF predictions for the screens modeled to be reproduced and novel screens to be simulated. Methods: The transport parameters of interest are the scattering efficiency (Q{sub sct}), absorption efficiency (Q{sub abs}), and the scatter anisotropy (g). Calculations of these parameters are made using the analytic method of Mie theory, for spherical grains of radii 0.1-5.0 {mu}m. The sensitivity of the transport parameters to emission wavelength is investigated using an emission spectrum representative of that of Gd{sub 2}O{sub 2}S:Tb. The impact of a grain-size distribution in the screen on the parameters is investigated using a Gaussian size-distribution ({sigma}= 1%, 5%, or 10% of mean radius). Two simple and novel alternative models to Mie theory are suggested: a geometrical optics and diffraction model (GODM) and an extension of this (GODM+). Comparisons to measured MTF are made for two commercial screens: Lanex Fast Back and Lanex Fast Front (Eastman Kodak Company, Inc.). Results: The Mie theory predictions of transport parameters were shown to be highly sensitive to both grain size

Fabrication and optical properties of type-II InP/InAs nanowire/quantum-dot heterostructures

Energy Technology Data Exchange (ETDEWEB)

Yan, Xin; Zhang, Xia; Li, Junshuai; Wu, Yao; Li, Bang; Ren, Xiaomin [State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing, 100876 (China)

2016-02-15

The growth and optical properties of InAs quantum dots on a pure zinc blende InP nanowire are investigated. The quantum dots are formed in Stranski-Krastanov mode and exhibit pure zinc blende crystal structure. A substantial blueshift of the dots peak with a cube-root dependence on the excitation power is observed, suggesting a type-II band alignment. The peak position of dots initially red-shifts and then blue-shifts with increasing temperature, which is attributed to the carrier redistribution among the quantum dots. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Paired emitter-detector light emitting diodes for the measurement of lead(II) and cadmium(II)

International Nuclear Information System (INIS)

Lau, K.-T.; McHugh, Eimear; Baldwin, Susan; Diamond, Dermot

2006-01-01

A transmittance mode optical device based on using a reverse biased light emitting diode (LED) as light detector has been developed for colorimetric analysis. This new optical device was validated with bromocresol green dye for absorbance measurements before being employed for detecting cadmium(II) and lead(II) in water. Results show that the performance of this LED-based device is comparable to much more expensive bench top UV-vis instruments, but with the advantages of being low cost, low power and simple to operate

Paired emitter-detector light emitting diodes for the measurement of lead(II) and cadmium(II)

Energy Technology Data Exchange (ETDEWEB)

Lau, K.-T. [Adaptive Sensors Group, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin 9 (Ireland)]. E-mail: kim.lau@dcu.ie; McHugh, Eimear [Adaptive Sensors Group, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin 9 (Ireland); Baldwin, Susan [Adaptive Sensors Group, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin 9 (Ireland); Diamond, Dermot [Adaptive Sensors Group, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin 9 (Ireland)]. E-mail: Dermot.diamond@dcu.ie

2006-05-31

A transmittance mode optical device based on using a reverse biased light emitting diode (LED) as light detector has been developed for colorimetric analysis. This new optical device was validated with bromocresol green dye for absorbance measurements before being employed for detecting cadmium(II) and lead(II) in water. Results show that the performance of this LED-based device is comparable to much more expensive bench top UV-vis instruments, but with the advantages of being low cost, low power and simple to operate.

Optical Landing Hazard Sensor, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Visidyne's Phase I effort has established through modeling and analysis that a unique concept for an active optical 3-D Imager (or Imaging LADAR) has high potential...

Switchable lasing in multimode microcavities

DEFF Research Database (Denmark)

Zhukovsky, Sergei V.; Chigrin, Dmitry N.; Lavrinenko, Andrei

2007-01-01

can be caused by injecting an appropriate optical pulse at the onset of laser action (injection seeding). Temporal mode-to-mode switching by reseeding the cavity after a short cooldown period is demonstrated by direct numerical solution. A qualitative analytical explanation of the mode switching...

Single photon sources with single semiconductor quantum dots

Science.gov (United States)

Shan, Guang-Cun; Yin, Zhang-Qi; Shek, Chan Hung; Huang, Wei

2014-04-01

In this contribution, we briefly recall the basic concepts of quantum optics and properties of semiconductor quantum dot (QD) which are necessary to the understanding of the physics of single-photon generation with single QDs. Firstly, we address the theory of quantum emitter-cavity system, the fluorescence and optical properties of semiconductor QDs, and the photon statistics as well as optical properties of the QDs. We then review the localization of single semiconductor QDs in quantum confined optical microcavity systems to achieve their overall optical properties and performances in terms of strong coupling regime, efficiency, directionality, and polarization control. Furthermore, we will discuss the recent progress on the fabrication of single photon sources, and various approaches for embedding single QDs into microcavities or photonic crystal nanocavities and show how to extend the wavelength range. We focus in particular on new generations of electrically driven QD single photon source leading to high repetition rates, strong coupling regime, and high collection efficiencies at elevated temperature operation. Besides, new developments of room temperature single photon emission in the strong coupling regime are reviewed. The generation of indistinguishable photons and remaining challenges for practical single-photon sources are also discussed.

Evaluation of the optical design of laser Thomson scattering diagnostics for high-temperature EAST tokamak and low-temperature MAP-II divertor simulator

International Nuclear Information System (INIS)

Kado, Shinichiro; Scotti, Filippo; Xi Xiaoqi; Zhao Junyu

2009-01-01

The optical design of the laser Thomson scattering (LTS) system for EAST tokamak is now on-going. Based on the Visible YAG laser TVTS system developed in the MAP-II (material and plasma) steady-state linear divertor/edge plasma simulator at the University of Tokyo, the required specification and the applicability of the VIS-YAG-TVTS system was evaluated in terms of the photon number to be collected by the fiber light-guide to a spectrometer and the reciprocal linear dispersion of the spectrometer. Then, the possible design of the optical system was proposed. (author)

White emission from nano-structured top-emitting organic light-emitting diodes based on a blue emitting layer

International Nuclear Information System (INIS)

Hyun, Woo Jin; Park, Jung Jin; Park, O Ok; Im, Sang Hyuk; Chin, Byung Doo

2013-01-01

We demonstrated that white emission can be obtained from nano-structured top-emitting organic light-emitting diodes (TEOLEDs) based on a blue emitting layer (EML). The nano-structured TEOLEDs were fabricated on nano-patterned substrates, in which both optical micro-cavity and scattering effects occur simultaneously. Due to the combination of these two effects, the electroluminescence spectra of the nano-structured device with a blue EML exhibited not only blue but also yellow colours, which corresponded to the intrinsic emission of the EML and the resonant emission of the micro-cavity effect. Consequently, it was possible to produce white emission from nano-structured TEOLEDs without employing a multimode micro-cavity. The intrinsic emission wavelength can be varied by altering the dopant used for the EML. Furthermore, the emissive characteristics turned out to be strongly dependent on the nano-pattern sizes of the nano-structured devices. (paper)

Active locking and entanglement in type II optical parametric oscillators

Science.gov (United States)

Ruiz-Rivas, Joaquín; de Valcárcel, Germán J.; Navarrete-Benlloch, Carlos

2018-02-01

Type II optical parametric oscillators are amongst the highest-quality sources of quantum-correlated light. In particular, when pumped above threshold, such devices generate a pair of bright orthogonally-polarized beams with strong continuous-variable entanglement. However, these sources are of limited practical use, because the entangled beams emerge with different frequencies and a diffusing phase difference. It has been proven that the use of an internal wave-plate coupling the modes with orthogonal polarization is capable of locking the frequencies of the emerging beams to half the pump frequency, as well as reducing the phase-difference diffusion, at the expense of reducing the entanglement levels. In this work we characterize theoretically an alternative locking mechanism: the injection of a laser at half the pump frequency. Apart from being less invasive, this method should allow for an easier real-time experimental control. We show that such an injection is capable of generating the desired phase locking between the emerging beams, while still allowing for large levels of entanglement. Moreover, we find an additional region of the parameter space (at relatively large injections) where a mode with well defined polarization is in a highly amplitude-squeezed state.

Synthesis, spectral and third-order nonlinear optical properties of terpyridine Zn(II) complexes based on carbazole derivative with polyether group

Science.gov (United States)

Kong, Ming; Liu, Yanqiu; Wang, Hui; Luo, Junshan; Li, Dandan; Zhang, Shengyi; Li, Shengli; Wu, Jieying; Tian, Yupeng

2015-01-01

Four novel Zn(II) terpyridine complexes (ZnLCl2, ZnLBr2, ZnLI2, ZnL(SCN)2) based on carbazole derivative group were designed, synthesized and fully characterized. Their photophysical properties including absorption and one-photon excited fluorescence, two-photon absorption (TPA) and optical power limiting (OPL) were further investigated systematically and interpreted on the basis of theoretical calculations (TD-DFT). The influences of different solvents on the absorption and One-Photon Excited Fluorescence (OPEF) spectral behavior, quantum yields and the lifetime of the chromophores have been investigated in detail. The third-order nonlinear optical (NLO) properties were investigated by open/closed aperture Z-scan measurements using femtosecond pulse laser in the range from 680 to 1080 nm. These results revealed that ZnLCl2 and ZnLBr2 exhibited strong two-photon absorption and ZnLCl2 showed superior optical power limiting property.

Optical propagation in linear media atmospheric gases and particles, solid-state components, and water

CERN Document Server

Thomas, Michael E

2006-01-01

PART I: Background Theory and Measurement. 1. Optical Electromagnetics I. 2. Optical Electromagnetics II. 3. Spectroscopy of Matter. 4. Electrodynamics I: Macroscopic Interaction of Light and Matter. 5. Electrodynamics II: Microscopic Interaction of Light and Matter. 6. Experimental Techniques. PART II: Practical Models for Various Media. 7. Optical Propagation in Gases and the Atmosphere of the Earth. 8. Optical Propagation in Solids. 9. Optical Propagation in Liquids. 10. Particle Absorption and Scatter. 11. Propagation Background and Noise

Light-induced switching in pDTE-FICO 1D photonic structures

Science.gov (United States)

Kriegel, Ilka; Scotognella, Francesco

2018-03-01

We propose the design of 1D photonic crystals and microcavities in which fluorine-indium codoped cadmium oxide (FICO) nanocrystal based layers and layers of diarylethene-based polyester (pDTE) are alternated or embedded in a microcavity. The irradiation with UV light results in two different behaviours: (i) it dopes the FICO nanocrystals inducing a blue shift of their plasmonic resonances; (ii) it changes the real part of the refractive index of the photochromic pDTE polymer. These two behaviours are combined in the proposed photonic structures and can be useful for switchable filters and cavities for light emission.

Time Inter-Comparison Using Transportable Optical Combs, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — AOSense proposes a free-space, two-way optical time transfer system compatible with global-scale synchronization of current-generation optical atomic clocks. In...

Optical and electronic properties of InGaAs and nitride quantum dots

Energy Technology Data Exchange (ETDEWEB)

Baer, N.

2006-06-15

In the present thesis, the electronic and optical properties of such nanostructures have been investigated for the well established III-V and the new group-III nitride material system. The influence of Coulomb correlations on the optical spectra of InGaAs QDs are studied using a full configuration interaction approach. The resulting multi-exciton spectra for up to twelve excitons are investigated in detail. Characteristic features of the spectra are explained using simplified Hamiltonians that are derived taking into account the relative importance of various interaction contributions. Additionally, we study the electronic and optical properties of self-assembled InN/GaN quantum dots. The existence of an exactly degenerate p-shell is discussed in detail. Dipole and Coulomb matrix elements are calculated from these one-particle wave functions and serve as an input for configuration interaction calculations. We present multi-exciton emission spectra and investigate how Coulomb correlations and oscillator strengths are altered by the built-in electrostatic fields present in these structures. From our results, we predict vanishing exciton and biexciton ground state emission for small lens-shaped dots, which is explained by a careful analysis of the underlying symmetry group. To study the photoluminescence dynamics of an initially excited QD system, we employ a microscopic semiconductor theory. Carrier-carrier correlations beyond the Hartee-Fock level are included within a cluster expansion truncation scheme up to the singlet-doublet level. The influence of these correlations on the spectrum and the photoluminescence dynamics is investigated for the emission into free space as well as for QDs embedded in an optical microcavity. (orig.)

Optical and electronic properties of InGaAs and nitride quantum dots

International Nuclear Information System (INIS)

Baer, N.

2006-06-01

In the present thesis, the electronic and optical properties of such nanostructures have been investigated for the well established III-V and the new group-III nitride material system. The influence of Coulomb correlations on the optical spectra of InGaAs QDs are studied using a full configuration interaction approach. The resulting multi-exciton spectra for up to twelve excitons are investigated in detail. Characteristic features of the spectra are explained using simplified Hamiltonians that are derived taking into account the relative importance of various interaction contributions. Additionally, we study the electronic and optical properties of self-assembled InN/GaN quantum dots. The existence of an exactly degenerate p-shell is discussed in detail. Dipole and Coulomb matrix elements are calculated from these one-particle wave functions and serve as an input for configuration interaction calculations. We present multi-exciton emission spectra and investigate how Coulomb correlations and oscillator strengths are altered by the built-in electrostatic fields present in these structures. From our results, we predict vanishing exciton and biexciton ground state emission for small lens-shaped dots, which is explained by a careful analysis of the underlying symmetry group. To study the photoluminescence dynamics of an initially excited QD system, we employ a microscopic semiconductor theory. Carrier-carrier correlations beyond the Hartee-Fock level are included within a cluster expansion truncation scheme up to the singlet-doublet level. The influence of these correlations on the spectrum and the photoluminescence dynamics is investigated for the emission into free space as well as for QDs embedded in an optical microcavity. (orig.)

Role of dust in H II regions

International Nuclear Information System (INIS)

Sarazin, C.L.

1975-01-01

The purpose of this dissertation is to determine quantitatively the effects of U.V. absorbing dust on H II regions, and compare these effects with observations. Many observations indicate that dust grains are present within H II regions. An analytic theory is presented which describes all three of the effects of dust in H II regions. Although this model is relatively crude, it is useful in determining the approximate size of the modifications due to dust. In order to explore this problem more carefully, detailed numerical models of H II regions with dust were constructed. The ionization and thermal structure of these model H II regions is discussed. The observational consequences of the presence of dust are explored; the optical line intensities, radio continuum and line fluxes, and infrared emission of model H II regions with dust are given. These numerical models are compared with observations of diffuse nebulae. The optical line ratios are compared to several nearby bright H II regions, and it is found that the dust models may explain several anomalies in their spectrum

Growth and characterization of dichlorobis L-proline Zn(II): A semiorganic nonlinear optical single crystal

Science.gov (United States)

Lydia Caroline, M.; Kandasamy, A.; Mohan, R.; Vasudevan, S.

2009-02-01

A semiorganic nonlinear optical material dichlorobis L-proline Zn (II) (DBLPZ), with molecular formula [ZnCl 2(C 5H 9NO 2) 2], has been synthesized from mixed solvents of deionised water and methanol. Single crystals of DBLPZ were successfully grown by the slow evaporation method at an ambient temperature. Single-crystal X-ray diffractometer was utilized to measure unit cell parameters and to confirm the crystal structure. The powder X-ray diffraction pattern of the grown DBLPZ has been indexed. The modes of vibration of different molecular groups present in the sample were identified by the FTIR spectral analysis. The optical transmittance window and the lower cutoff wavelength of the DBLPZ have been identified by UV-vis-NIR studies. Thermal stability of the DBLPZ was determined from TG/DTA/DSC curves, which indicate that the material is stable up to 242.3 °C. The existence of second harmonic generation signals was observed using Nd:YAG laser with fundamental wavelength of 1064 nm possessing SHG efficiency of 0.5 times of KDP and hence it can be a potential material for the frequency-doubling process.

Methods for polarized light emission from CdSe quantum dot based monolithic pillar microcavities

Energy Technology Data Exchange (ETDEWEB)

Seyfried, Moritz; Kalden, Joachim; Sebald, Kathrin; Gutowski, Juergen; Kruse, Carsten; Hommel, Detlef [Institute of Solid State Physics, University of Bremen (Germany)

2010-07-01

A lifting of the polarization degeneracy of the fundamental cavity mode in pillar microcavities (MCs) would allow for controlling the polarization state of the emitted photons. Therefore, monolithic VCSEL structures were grown by molecular beam epitaxy containing either one CdSe/ZnSSe quantum dot layer or three quantum well layers as active material. By using focused-ion-beam etching, MC pillars with different geometries were prepared out of the planar samples. Among these are circularly shaped pillar MCs with diameters in the range from 500 nm up to 4 {mu}m and quality factors of up to 7860, elliptically shaped MCs, and so-called photonic molecules consisting of circular pillar MCs which are connected by small bars. Polarization dependent photoluminescence investigations of the fundamental cavity mode reveal a lifting of the polarization degeneracy for all three types of MCs. The energy splitting of up to 0.42 meV in the circularly shaped pillar MCs is probably caused by anisotropic strain conditions within the sample and directly dependent on the pillar diameter, whereas the larger energy splitting of up to 0.72 meV for the photonic molecules or even 4.5 meV for the elliptically shaped MC is based on their asymmetric cross sections.

21 CFR 872.3661 - Optical Impression Systems for CAD/CAM.

Science.gov (United States)

2010-04-01

... of sensor and a computer with software. (b) Classification. Class II (Special Controls). The device... entitled “Class II Special Controls Guidance Document: Optical Impression Systems for Computer Assisted.../CAM. (a) Identification. An optical impression system for computer assisted design and manufacturing...

Cancelation of thermally induced frequency shifts in bimaterial cantilevers by nonlinear optomechanical interactions

Energy Technology Data Exchange (ETDEWEB)

Vy, Nguyen Duy, E-mail: nguyenduyvy@tdt.edu.vn [Theoretical Physics Research Group, Ton Duc Thang University, Ho Chi Minh City 756636 (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City 756636 (Viet Nam); Tri Dat, Le [Faculty of Physics and Engineering Physics, University of Science, Ho Chi Minh City 748355 (Viet Nam); Iida, Takuya [Department of Physical Science, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531 (Japan)

2016-08-01

Bimaterial cantilevers have recently been used in, for example, the calorimetric analysis with picowatt resolution in microscopic space based on state-of-the-art atomic force microscopes. However, thermally induced effects usually change physical properties of the cantilevers, such as the resonance frequency, which reduce the accuracy of the measurements. Here, we propose an approach to circumvent this problem that uses an optical microcavity formed between a metallic layer coated on the back of the cantilever and one coated at the end of an optical fiber irradiating the cantilever. In addition to increasing the sensitivity, the optical rigidity of this system diminishes the thermally induced frequency shift. For a coating thickness of several tens of nanometers, the input power is 5–10 μW. These values can be evaluated from parameters derived by directly irradiating the cantilever in the absence of the microcavity. The system has the potential of using the cantilever both as a thermometer without frequency shifting and as a sensor with nanometer-controlled accuracy.

Digital optical interconnects for photonic computing

Science.gov (United States)

Guilfoyle, Peter S.; Stone, Richard V.; Zeise, Frederick F.

1994-05-01

A 32-bit digital optical computer (DOC II) has been implemented in hardware utilizing 8,192 free-space optical interconnects. The architecture exploits parallel interconnect technology by implementing microcode at the primitive level. A burst mode of 0.8192 X 1012 binary operations per sec has been reliably demonstrated. The prototype has been successful in demonstrating general purpose computation. In addition to emulating the RISC instruction set within the UNIX operating environment, relational database text search operations have been implemented on DOC II.

Comments on the paper: 'Optical reflectance, optical refractive index and optical conductivity measurements of nonlinear optics for L-aspartic acid nickel chloride single crystal'

Science.gov (United States)

Srinivasan, Bikshandarkoil R.; Naik, Suvidha G.; Dhavskar, Kiran T.

2016-02-01

We argue that the 'L-aspartic acid nickel chloride' crystal reported by the authors of the title paper (Optics Communications, 291 (2013) 304-308) is actually the well-known diaqua(L-aspartato)nickel(II) hydrate crystal.

Fiber Optic Pressure Sensor Array, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — VIP Sensors proposes to develop a Fiber Optic Pressure Sensor Array System for measuring air flow pressure at multiple points on the skin of aircrafts for Flight...

Growth of self-assembled (Ga)InAs/GaAs quantum dots and realization of high quality microcavities for experiments in the field of strong exciton photon coupling; Selbstorganisiertes Wachstum von (Ga)InAs/GaAs-Quantenpunkten und Entwicklung von Mikroresonatoren hoechster Guete fuer Experimente zur starken Exziton-Photon-Kopplung

Energy Technology Data Exchange (ETDEWEB)

Loeffler, Andreas

2008-11-05

At the beginning, we improved the three dimensional optical confinement of the micropillars. The quality factor of the pillars could be increased by the use of higher reflectivity mirrors and a matched V/III ratio for the different epitaxial layers. Hence, a record quality factor of about 90000 was achieved for an active micropillar with 26 (30) mirror pairs in the top (bottom) DBR and a diameter of 4 {mu}m. In parallel to this, we made studies on the growth of self-assembled GaInAs quantum dots on GaAs substrates. Here, the nucleation of three dimensional islands as well as their optical properties were object of the investigation. The morphological properties of the dots were analyzed by transmission and scanning electron microscopy, and the optical properties were investigated by photoluminescence and photoreflectance measurements. The optical and particularly the morphological properties of the self-assembled GaInAs quantum dots were essentially improved. Due to a low strain nucleation layer with an indium content of 30 %, the dot density could be reduced to 6-9 x 10{sup 9} cm{sup -2} and their geometric dimensions were increased to typical lengths between 50 and 100 nm and widths of about 30 nm. The lattice mismatch between the quantum dots and the surrounding matrix is decreased due to the reduced indium content. The minimized strain during the dot growth leads to an enhanced migration length of the deposited atoms on the surface. Finally, the obtained findings of the MBE growth of microcavities, their fabrication and the self-assembled island growth of GaInAs on GaAs were used for the realization of further samples. Low strain GaInAs quantum dots were embedded into the microresonators. These structures allowed for the first time the observation of strong coupling between light and matter in a semiconductor. In case of the low strain quantum dots with enlarged dimensions in the strong coupling regime, a vacuum Rabi-splitting of about 140 {mu}eV between the

Time-domain scanning optical mammography: II. Optical properties and tissue parameters of 87 carcinomas

International Nuclear Information System (INIS)

Grosenick, Dirk; Wabnitz, Heidrun; Moesta, K Thomas; Mucke, Joerg; Schlag, Peter M; Rinneberg, Herbert

2005-01-01

Within a clinical trial on scanning time-domain optical mammography reported on in a companion publication (part I), craniocaudal and mediolateral projection optical mammograms were recorded from 154 patients, suspected of having breast cancer. Here we report on in vivo optical properties of the subset of 87 histologically validated carcinomas which were visible in optical mammograms recorded at two or three near-infrared wavelengths. Tumour absorption and reduced scattering coefficients were derived from distributions of times of flight of photons recorded at the tumour site employing the model of diffraction of photon density waves by a spherical inhomogeneity, located in an otherwise homogeneous tissue slab. Effective tumour radii, taken from pathology, and tumour location along the compression direction, deduced from off-axis optical scans of the tumour region, were included in the analysis as prior knowledge, if available. On average, tumour absorption coefficients exceeded those of surrounding healthy breast tissue by a factor of about 2.5 (670 nm), whereas tumour reduced scattering coefficients were larger by about 20% (670 nm). From absorption coefficients at 670 nm and 785 nm total haemoglobin concentration and blood oxygen saturation were deduced for tumours and surrounding healthy breast tissue. Apart from a few outliers total haemoglobin concentration was observed to be systematically larger in tumours compared to healthy breast tissue. In contrast, blood oxygen saturation was found to be a poor discriminator for tumours and healthy breast tissue; both median values of blood oxygen saturation are the same within their statistical uncertainties. However, the ratio of total haemoglobin concentration over blood oxygen saturation further improves discrimination between tumours and healthy breast tissue. For 29 tumours detected in optical mammograms recorded at three wavelengths (670 nm, 785 nm, 843 nm or 884 nm), scatter power was derived from transport

Harnessing Light with Photonic Nanowires: Fundamentals and Applications to Quantum Optics

DEFF Research Database (Denmark)

Claudon, Julien; Gregersen, Niels; Lalanne, Philippe

2013-01-01

the Purcell effect that arises in a resonant microcavity. Recently, the need to relax the constraints inherent to such a narrow-band approach has motivated large effort to develop structures ensuring broadband and efficient SE control. This minireview deals with fiber-like photonic nanowires, a class of high...

Controlling light emission from single-photon sources using photonic nanowires

DEFF Research Database (Denmark)

Gregersen, Niels; Chen, Yuntian; Mørk, Jesper

2012-01-01

The photonic nanowire has recently emerged as an promising alternative to microcavity-based single-photon source designs. In this simple structure, a geometrical effect ensures a strong coupling between an embedded emitter and the optical mode of interest and a combination of tapers and mirrors a...

Visualising Berry phase and diabolical points in a quantum exciton-polariton billiard.

Science.gov (United States)

Estrecho, E; Gao, T; Brodbeck, S; Kamp, M; Schneider, C; Höfling, S; Truscott, A G; Ostrovskaya, E A

2016-11-25

Diabolical points (spectral degeneracies) can naturally occur in spectra of two-dimensional quantum systems and classical wave resonators due to simple symmetries. Geometric Berry phase is associated with these spectral degeneracies. Here, we demonstrate a diabolical point and the corresponding Berry phase in the spectrum of hybrid light-matter quasiparticles-exciton-polaritons in semiconductor microcavities. It is well known that sufficiently strong optical pumping can drive exciton-polaritons to quantum degeneracy, whereby they form a macroscopically populated quantum coherent state similar to a Bose-Einstein condensate. By pumping a microcavity with a spatially structured light beam, we create a two-dimensional quantum billiard for the exciton-polariton condensate and demonstrate a diabolical point in the spectrum of the billiard eigenstates. The fully reconfigurable geometry of the potential walls controlled by the optical pump enables a striking experimental visualization of the Berry phase associated with the diabolical point. The Berry phase is observed and measured by direct imaging of the macroscopic exciton-polariton probability densities.

Cavity plasmon polaritons in monolayer graphene

International Nuclear Information System (INIS)

Kotov, O.V.; Lozovik, Yu.E.

2011-01-01

Plasmon polaritons in a new system, a monolayer doped graphene embedded in optical microcavity, are studied here. The dispersion law for lower and upper cavity plasmon polaritons is obtained. Peculiarities of Rabi splitting for the system are analyzed; particularly, role of Dirac-like spinor (envelope) wave functions in graphene and corresponding angle factors are considered. Typical Rabi frequencies for maximal (acceptable for Dirac-like electron spectra) Fermi energy and frequencies of polaritons near polariton gap are estimated. The plasmon polaritons in considered system can be used for high-speed information transfer in the THz region. -- Highlights: → Plasmon polaritons in a monolayer doped graphene embedded in optical microcavity, are studied here. → The dispersion law for lower and upper cavity plasmon polaritons is obtained. → Peculiarities of Rabi splitting for the system are analyzed. → Role of Dirac-like wave functions in graphene and corresponding angle factors are considered. → Typical Rabi frequencies and frequencies of polaritons near polariton gap are estimated.

Detection of Myoglobin with an Open-Cavity-Based Label-Free Photonic Crystal Biosensor.

Science.gov (United States)

Zhang, Bailin; Tamez-Vela, Juan Manuel; Solis, Steven; Bustamante, Gilbert; Peterson, Ralph; Rahman, Shafiqur; Morales, Andres; Tang, Liang; Ye, Jing Yong

2013-01-01

The label-free detection of one of the cardiac biomarkers, myoglobin, using a photonic-crystal-based biosensor in a total-internal-reflection configuration (PC-TIR) is presented in this paper. The PC-TIR sensor possesses a unique open optical microcavity that allows for several key advantages in biomolecular assays. In contrast to a conventional closed microcavity, the open configuration allows easy functionalization of the sensing surface for rapid biomolecular binding assays. Moreover, the properties of PC structures make it easy to be designed and engineered for operating at any optical wavelength. Through fine design of the photonic crystal structure, biochemical modification of the sensor surface, and integration with a microfluidic system, we have demonstrated that the detection sensitivity of the sensor for myoglobin has reached the clinically significant concentration range, enabling potential usage of this biosensor for diagnosis of acute myocardial infarction. The real-time response of the sensor to the myoglobin binding may potentially provide point-of-care monitoring of patients and treatment effects.

MBE-grown semiconductor nanostructures with electronic and photonic confinement

DEFF Research Database (Denmark)

Jensen, Jacob Riis

In this thesis the realization of semiconductor nanostructures in the InAlGaAs material system with molecular beam epitaxy (MBE) is described, as well as the characterization of their optical properties. First, the growth conditions used for different materials and surfaces are given, and the gen...... a microcavity is measured and analysed, where a good qualitative agreement with theories for Rayleigh scattering is found, ant he so-called polariton bottleneck is observed....... well is also taken into account, which is demonstrated in a microcavity with a reduced light-matter interaction. For the polariton with the lowest eigenenergy, it is shown that the probability for scattering on lattice vibrations or free carriers is reduced. Finally, the secondary emission from...

Room-temperature light-emission from Ge quantum dots in photonic crystals

Energy Technology Data Exchange (ETDEWEB)

Xia Jinsong [Advanced Research Laboratories, Musashi Institute of Technolgy, 8-15-1 Todoroki, Setagaya-ku, Tokyo 158-0082 (Japan)], E-mail: jxia@sc.musashi-tech.ac.jp; Nemoto, Koudai; Ikegami, Yuta [Advanced Research Laboratories, Musashi Institute of Technolgy, 8-15-1 Todoroki, Setagaya-ku, Tokyo 158-0082 (Japan); Usami, Noritaka [Institute of Materials Research, Tohoku University, 2-2-1 Katahira, Aoba-ku, Sendai Japan (Japan)], E-mail: usa@imr.tohoku.ac.jp; Nakata, Yasushi [Horiba, Ltd., 1-7-8 Higashi-Kanda, Chiyoda-ku, Tokyo 101-0031 (Japan)], E-mail: yasushi.nakata@horiba.com; Shiraki, Yasuhiro [Advanced Research Laboratories, Musashi Institute of Technolgy, 8-15-1 Todoroki, Setagaya-ku, Tokyo 158-0082 (Japan)

2008-11-03

Multiple layers of Ge self-assembled quantum dots were embedded into two-dimensional silicon photonic crystal microcavities fabricated on silicon-on-insulator substrates. Microphotoluminescence was used to study the light-emission characteristic of the Ge quantum dots in the microcavities. Strong resonant room-temperature light-emission was observed in the telecommunication wavelength region. Significant enhancement of the luminescence from Ge dots was obtained due to the resonance in the cavities. Multiple sharp resonant peaks dominated the spectrum, showing strong optical resonance inside the cavity. By changing the lattice constant of photonic crystal structure, the wavelengths of the resonant peaks are tuned in the wide wavelength range from 1.2 to 1.6 {mu}m.

Nonlinear optical and G-Quadruplex DNA stabilization properties of novel mixed ligand copper(II) complexes and coordination polymers: Synthesis, structural characterization and computational studies

Science.gov (United States)

Rajasekhar, Bathula; Bodavarapu, Navya; Sridevi, M.; Thamizhselvi, G.; RizhaNazar, K.; Padmanaban, R.; Swu, Toka

2018-03-01

The present study reports the synthesis and evaluation of nonlinear optical property and G-Quadruplex DNA Stabilization of five novel copper(II) mixed ligand complexes. They were synthesized from copper(II) salt, 2,5- and 2,3- pyridinedicarboxylic acid, diethylenetriamine and amide based ligand (AL). The crystal structure of these complexes were determined through X-ray diffraction and supported by ESI-MAS, NMR, UV-Vis and FT-IR spectroscopic methods. Their nonlinear optical property was studied using Gaussian09 computer program. For structural optimization and nonlinear optical property, density functional theory (DFT) based B3LYP method was used with LANL2DZ basis set for metal ion and 6-31G∗ for C,H,N,O and Cl atoms. The present work reveals that pre-polarized Complex-2 showed higher β value (29.59 × 10-30e.s.u) as compared to that of neutral complex-1 (β = 0.276 × 10-30e.s.u.) which may be due to greater advantage of polarizability. Complex-2 is expected to be a potential material for optoelectronic and photonic technologies. Docking studies using AutodockVina revealed that complex-2 has higher binding energy for both G-Quadruplex DNA (-8.7 kcal/mol) and duplex DNA (-10.1 kcal/mol). It was also observed that structure plays an important role in binding efficiency.

Biexciton dephasing in a semiconductor microcavity

DEFF Research Database (Denmark)

Borri, P.; Langbein, W.; Woggon, U.

2001-01-01

the heavy-hole (HH) vacuum Rabi splitting is 3.6 meV, more than three times larger than the biexciton binding energy in the bare QW (1.1 meV). Due to the narrow linewidth of the polariton resonances, a well-resolved pump-induced optical absorption associated with biexcitons was observed. In this work we...

Combined Electrical, Optical and Nuclear Investigations of Impurities and Defects in II-VI Semiconductors

CERN Multimedia

2002-01-01

% IS325 \\\\ \\\\ To achieve well controlled bipolar conductivity in II-VI semiconductors represents a fundamental problem in semiconductor physics. The doping problems are controversely discussed, either in terms of self compensation or of compensation and passivation by unintentionally introduced impurities. \\\\ \\\\It is the goal of our experiments at the new ISOLDE facility, to shed new light on these problems and to look for ways to circumvent it. For this aim the investigation of impurities and native defects and the interaction between each other shall be investigated. The use of radioactive ion beams opens the access to controlled site selective doping of only one sublattice via nuclear transmutation. The compensating and passivating mechanisms will be studied by combining nuclear, electrical and optical methods like Perturbed Angular Correlation~(PAC), Hall Effect~(HE), Deep Level Transient Spectroscopy~(DLTS), Photoluminescence Spectroscopy~(PL) and electron paramagnetic resonance (EPR). \\\\ \\\\We intend to ...

Measurements of Extensive Aerosol Optical Properties During TexAQS II: Implications for PM Compliance and Planning

Science.gov (United States)

Wright, M. E.; Atkinson, D. B.; Luke, W. T.

2007-12-01

In 2000, the Houston-Galveston Area (HGA) was designated as a non-attainment area for several criteria air pollutants by the US EPA. In order to meet the requirements of the federal Clean Air Act, the Second Texas Air Quality Study (TexAQS II) was designed to update the State Implementation Plan (SIP) by providing scientific air quality data over 18 months from June 2005 to October 2006. The data presented here was collected as part of the Texas Radical and Aerosol Measurement Program (TRAMP), a substudy of TexAQS II. Bulk aerosol optical properties were measured for six weeks atop the 60 m high Southwest Moody Tower on the University of Houston campus. The measurements were collected using a cavity ring-down transmissometer/nephelometer (CRDT/N) and consisted of the extensive aerosol coefficients: extinction (bext) at 532 and 1064 nm and scattering (bscat) at 530nm. In addition to daily and whole study averages and calculated mass values, positive correlations between the 1064 nm extinction and 532 nm absorption (babs = bext - bscat) values are displayed for this study period for the first time. Correlation between the particle scattering coefficient and the sum of AMS measured (UNH - PI: R. Griffin) sulfate and organic particle mass concentrations as well as covariance between optical properties and O3, CO and NOx values (ARL/NOAA - PI: W. Luke) are also examined. No correlation is expected between coarse particles (PM10), which are typically primary biogenic suspended soil minerals or windblown dust, and high ozone concentrations. Ozone levels are highest during periods of low wind when coarse particulate is likely to be at a minimum. On the other hand, secondary particles and O3 should be correlated on short time scales because both species tend to have the same precursors, NOx and VOC's, and formation of particles is favored during stagnant conditions. Fine particles (PM2.5) should also correlate with CO since both species have a common emission source. Wind

Quantum complementarity of cavity photons coupled to a three-level system

International Nuclear Information System (INIS)

Vilardi, R.; Savasta, S.; Di Stefano, O.; Ridolfo, A.; Portolan, S.

2011-01-01

Recently a device enabling the ultrafast all-optical control of the wave-particle duality of light was proposed [Ridolfo et al., Phys. Rev. Lett. 106, 013601 (2011)]. It is constituted by a three-level quantum emitter strongly coupled to a microcavity and can be realized by exploiting a great variety of systems ranging from atomic physics and semiconductor quantum dots to intersubband polaritons and Cooper pair boxes. Control pulses with specific arrival times, performing which-path and quantum-eraser operations, are able to destroy and recover interference almost instantaneously. Here we show that the coherence sudden death implies the sudden birth of a higher order correlation function storing coherence. Such storing enables coherence rebirth after the arrival of an additional suitable control pulse. We derive analytical calculations describing the all-optical control of the wave-particle duality and the entanglement-induced switch-off of the strong coupling regime. We also present analytical calculations describing a homodynelike method exploiting pairs of phase locked pulses with precise arrival times to probe the optical control of wave-particle duality of this system. Within such a method the optical control of wave-particle duality can be directly probed by just detecting the photons escaping the microcavity.

Photonic emitters and circuits based on colloidal quantum dot composites

Science.gov (United States)

Menon, Vinod M.; Husaini, Saima; Valappil, Nikesh; Luberto, Matthew

2009-02-01

We discuss our work on light emitters and photonic circuits realized using colloidal quantum dot composites. Specifically we will report our recent work on flexible microcavity laser, microdisk emitters and integrated active - passive waveguides. The entire microcavity laser structure was realized using spin coating and consisted of an all-polymer distributed Bragg reflector with a poly-vinyl carbazole cavity layer embedded with InGaP/ZnS colloidal quantum dots. These microcavities can be peeled off the substrate yielding a flexible structure that can conform to any shape and whose emission spectra can be mechanically tuned. The microdisk emitters and the integrated waveguide structures were realized using soft lithography and photo-lithography, respectively and were fabricated using a composite consisting of quantum dots embedded in SU8 matrix. Finally, we will discuss the effect of the host matrix on the optical properties of the quantum dots using results of steady-state and time-resolved luminescence measurements. In addition to their specific functionalities, these novel device demonstrations and their development present a low cost alternative to the traditional photonic device fabrication techniques.

ITK optical links backup document

CERN Document Server

Huffman, B T; The ATLAS collaboration; Flick, T; Ye, J

2013-01-01

This document describes the proposed optical links to be used for the ITK in the phase II upgrade. The current R&D for optical links pursued in the Versatile Link group is reviewed. In particular the results demonstrating the radiation tolerance of all the on-detector components are documented. The bandwidth requirements and the resulting numerology are given.

Mo/Si multilayers with enhanced TiO II- and RuO II-capping layers

Science.gov (United States)

Yulin, Sergiy; Benoit, Nicolas; Feigl, Torsten; Kaiser, Norbert; Fang, Ming; Chandhok, Manish

2008-03-01

The lifetime of Mo/Si multilayer-coated projection optics is one of the outstanding issues on the road of commercialization of extreme-ultraviolet lithography (EUVL). The application of Mo/Si multilayer optics in EUVL requires both sufficient radiation stability and also the highest possible normal-incidence reflectivity. A serious problem of conventional high-reflective Mo/Si multilayers capped by silicon is the considerable degradation of reflective properties due to carbonization and oxidation of the silicon surface layer under exposure by EUV radiation. In this study, we focus on titanium dioxide (TiO II) and ruthenium dioxide (RuO II) as promising capping layer materials for EUVL multilayer coatings. The multilayer designs as well as the deposition parameters of the Mo/Si systems with different capping layers were optimized in terms of maximum peak reflectivity at the wavelength of 13.5 nm and longterm stability under high-intensive irradiation. Optimized TiO II-capped Mo/Si multilayer mirrors with an initial reflectivity of 67.0% presented a reflectivity drop of 0.6% after an irradiation dose of 760 J/mm2. The reflectivity drop was explained by the partial oxidation of the silicon sub-layer. No reflectivity loss after similar irradiation dose was found for RuO II-capped Mo/Si multilayer mirrors having initial peak reflectivity of 66%. In this paper we present data on improved reflectivity of interface-engineered TiO II- and RuO II-capped Mo/Si multilayer mirrors due to the minimization of both interdiffusion processes inside the multilayer stack and absorption loss in the oxide layer. Reflectivities of 68.5% at the wavelength of 13.4 nm were achieved for both TiO II- and RuO II-capped Mo/Si multilayer mirrors.

Nano-optical conveyor belt, part II: Demonstration of handoff between near-field optical traps.

Science.gov (United States)

Zheng, Yuxin; Ryan, Jason; Hansen, Paul; Cheng, Yao-Te; Lu, Tsung-Ju; Hesselink, Lambertus

2014-06-11

Optical tweezers have been widely used to manipulate biological and colloidal material, but the diffraction limit of far-field optics makes focused beams unsuitable for manipulating nanoscale objects with dimensions much smaller than the wavelength of light. While plasmonic structures have recently been successful in trapping nanoscale objects with high positioning accuracy, using such structures for manipulation over longer range has remained a significant challenge. In this work, we introduce a conveyor belt design based on a novel plasmonic structure, the resonant C-shaped engraving (CSE). We show how long-range manipulation is made possible by means of handoff between neighboring CSEs, and we present a simple technique for controlling handoff by rotating the polarization of laser illumination. We experimentally demonstrate handoff between a pair of CSEs for polystyrene spheres 200, 390, and 500 nm in diameter. We then extend this technique and demonstrate controlled particle transport down a 4.5 μm long "nano-optical conveyor belt."

High-Frequency Flush Mounted Miniature LOX Fiber-Optic Pressure Sensor II, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Luna Innovations has teamed with the University of Alabama, Huntsville, to develop a miniature flush-mounted fiber-optic pressure sensor that will allow accurate,...

Optical observations of the nearby galaxy IC342 with narrow band [SII] and hα filters. II - detection of 16 optically-identified supernova remnant candidates

Directory of Open Access Journals (Sweden)

Vučetić M.M.

2015-01-01

Full Text Available We present the detection of 16 optical supernova remnant (SNR candidates in the nearby spiral galaxy IC342. The candidates were detected by applying the [Sii]/Hα ratio criterion on observations made with the 2 m RCC telescope at Rozhen National Astronomical Observatory in Bulgaria. In this paper, we report the coordinates, diameters, Hα and [S ii] fluxes for 16 SNRs detected in two fields of view in the IC342 galaxy. Also, we estimate the contamination of total Hα flux from SNRs in the observed portion of IC342 to be 1.4%. This would represent the fractional error when the star formation rate (SFR for this galaxy is derived from the total galaxy’s Hα emission.

A fiber-optic polarimetric demonstration kit

International Nuclear Information System (INIS)

Eftimov, T; Dimitrova, T L; Ivanov, G

2012-01-01

A simple and multifunctional fiber-optic polarimetric kit on the basis of highly birefringent single-mode fibers is presented. The fiber-optic polarimetric kit allows us to perform the following laboratory exercises: (i) fiber excitation and the measurement of numerical aperture, (ii) polarization preservation and (iii) obtain polarization-sensitive fiberized interferometers.

ALFALFA DISCOVERY OF THE NEARBY GAS-RICH DWARF GALAXY LEO P. II. OPTICAL IMAGING OBSERVATIONS

Energy Technology Data Exchange (ETDEWEB)

Rhode, Katherine L.; Salzer, John J.; Haurberg, Nathalie C.; Van Sistine, Angela; Young, Michael D. [Department of Astronomy, Indiana University, 727 East Third Street, Bloomington, IN 47405 (United States); Haynes, Martha P.; Giovanelli, Riccardo; Adams, Elizabeth A. K. [Center for Radiophysics and Space Research, Space Sciences Building, Cornell University, Ithaca, NY 14853 (United States); Cannon, John M. [Department of Physics and Astronomy, Macalester College, Saint Paul, MN 55105 (United States); Skillman, Evan D.; McQuinn, Kristen B. W., E-mail: rhode@astro.indiana.edu, E-mail: slaz@astro.indiana.edu, E-mail: riccardo@astro.cornell.edu, E-mail: haynes@astro.cornell.edu, E-mail: betsey@astro.cornell.edu, E-mail: jcannon@macalester.edu, E-mail: skillman@astro.umn.edu, E-mail: kmcquinn@astro.umn.edu [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455 (United States)

2013-06-15

We present results from ground-based optical imaging of a low-mass dwarf galaxy discovered by the ALFALFA 21 cm H I survey. Broadband (BVR) data obtained with the WIYN 3.5 m telescope at Kitt Peak National Observatory (KPNO) are used to construct color-magnitude diagrams of the galaxy's stellar population down to V{sub o} {approx} 25. We also use narrowband H{alpha} imaging from the KPNO 2.1 m telescope to identify a H II region in the galaxy. We use these data to constrain the distance to the galaxy to be between 1.5 and 2.0 Mpc. This places Leo P within the Local Volume but beyond the Local Group. Its properties are extreme: it is the lowest-mass system known that contains significant amounts of gas and is currently forming stars.

Integration of Magneto-Optical Materials for Novel Optical Devices & Magnetophotonic Crystals, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This work proposes to capitalize on our Phase I success in monolithically integrating magneto-optic and magnetic materials with semiconductor platforms in order to...

Astronomical optical interferometry, II: Astrophysical results

Directory of Open Access Journals (Sweden)

Jankov S.

2011-01-01

Full Text Available Optical interferometry is entering a new age with several ground- based long-baseline observatories now making observations of unprecedented spatial resolution. Based on a great leap forward in the quality and quantity of interferometric data, the astrophysical applications are not limited anymore to classical subjects, such as determination of fundamental properties of stars; namely, their effective temperatures, radii, luminosities and masses, but the present rapid development in this field allowed to move to a situation where optical interferometry is a general tool in studies of many astrophysical phenomena. Particularly, the advent of long-baseline interferometers making use of very large pupils has opened the way to faint objects science and first results on extragalactic objects have made it a reality. The first decade of XXI century is also remarkable for aperture synthesis in the visual and near-infrared wavelength regimes, which provided image reconstructions from stellar surfaces to Active Galactic Nuclei. Here I review the numerous astrophysical results obtained up to date, except for binary and multiple stars milliarcsecond astrometry, which should be a subject of an independent detailed review, taking into account its importance and expected results at microarcsecond precision level. To the results obtained with currently available interferometers, I associate the adopted instrumental settings in order to provide a guide for potential users concerning the appropriate instruments which can be used to obtain the desired astrophysical information.

Polarization ray tracing in anisotropic optically active media. II. Theory and physics

International Nuclear Information System (INIS)

McClain, S.C.; Hillman, L.W.; Chipman, R.A.

1993-01-01

Refraction, reflection, and amplitude relations are derived that apply to polarization ray tracing in anisotropic, optically active media such as quartz. The constitutive relations for quartz are discussed. The refractive indices and polarization states associated with the two modes of propagation are derived as a function of wave direction. A procedure for refracting at any uniaxial or optically active interface is derived that computes both the ray direction and the wave direction. A method for computing the optical path length is given, and Fresnel transmission and ref lection equations are derived from boundary conditions on the electromagnetic fields. These ray-tracing formulas apply to uniaxial, optically active media and therefore encompass uniaxial, non-optically active materials and isotropic, optically active materials

Nonlinear and quantum optics with liquid crystals

International Nuclear Information System (INIS)

Lukishova, Svetlana G

2014-01-01

Thermotropic liquid crystals' usual application is display technology. This paper describes experiments on light interaction with pure and doped liquid crystals under for these materials unconventional incident light powers: (1) under high-power laser irradiation, and (2) at the single-photon level. In (1), I will outline several nonlinear optical effects under high-power, nanosecond laser irradiation which should be taken into account in the design of lasers with liquid crystal components and in fabrication of optical power limiters based on liquid crystals: (1.1) athermal helical pitch dilation and unwinding of cholesteric mirrors (both in free space and inside laser resonators); (1.2) some pitfalls in measurements of refractive nonlinearity using z-scan technique under two-photon or linear absorption of liquids; (1.3) the first observation of thermal lens effects in liquid crystals under several-nanosecond, low-pulse-repetition rate (2-10 Hz) laser irradiation in the presence of two-photon absorption; (1.4) feedback-free kaleidoscope of patterns (hexagons, stripes, etc.) in dye-doped liquid crystals. In (2), at the single-photon level, it will be shown that with a proper selection of liquid crystals and a single-emitter dopant spectral range, liquid crystal structures can be used to control emitted single photons (both polarization and count rate). The application of the latter research is absolutely secure quantum communication with polarization coding of information. In particular, in (2.1), definite handedness, circular polarized cholesteric microcavity resonance in quantum dot fluorescence is reported. In (2.2), definite linear polarization of single (antibunched) photons from single-dye-molecules in planar-aligned nematic host is discussed. In (2.3), some results on photon antibunching from NV-color center in nanodiamond in liquid crystal host and circularly polarized fluorescence of definite handedness from nanocrystals doped with trivalent ions of

Slow light effect with high group index and wideband by saddle-like mode in PC-CROW

Science.gov (United States)

Wan, Yong; Jiang, Li-Jun; Xu, Sheng; Li, Meng-Xue; Liu, Meng-Nan; Jiang, Cheng-Yi; Yuan, Feng

2018-04-01

Slow light with high group index and wideband is achieved in photonic crystal coupled-resonator optical waveguides (PC-CROWs). According to the eye-shaped scatterers and various microcavities, saddle-like curves between the normalized frequency f and wave number k can be obtained by adjusting the parameters of the scatterers, parameters of the coupling microcavities, and positions of the scatterers. Slow light with decent flat band and group index can then be achieved by optimizing the parameters. Simulations prove that the maximal value of the group index is > 104, and the normalized delay bandwidth product within a new varying range of n g > 102 or n g > 103 can be a new and effective criterion of evaluation for the slow light in PC-CROWs.

Crew Cerebral Oxygen Monitor, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This Phase II SBIR proposal is aimed at developing a non-invasive, optical method for monitoring crew member state of awareness in operational environments. All...

Effect of temperature on the optical and structural properties of hexadecylamine capped ZnS nanoparticles using Zinc(II) N-ethyl-N-phenyldithiocarbamate as single source precursor

Energy Technology Data Exchange (ETDEWEB)

Onwudiwe, Damian C., E-mail: dconwudiwe@webmail.co.za [Chemical Resource Beneficiation, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa); Strydom, Christien [Chemical Resource Beneficiation, North-West University, Private Bag X6001, Potchefstroom 2520 (South Africa); Oluwafemi, Oluwatobi S., E-mail: oluwafemi.oluwatobi@gmail.com [Department of Chemistry and Chemical Technology, Walter Sisulu University, Mthatha Campus, Private Bag X1, Mthatha (South Africa); Songca, Sandile P. [Faculty of Science, Engineering and Technology, Walter Sisulu University, P.O. Box 19712, Tecoma, East London (South Africa)

2012-12-15

Graphical abstract: Display Omitted Highlights: ► HDA-capped ZnS nanoparticles were synthesized via thermolysis of a single source precursor. ► Zinc(II) N-ethyl-N-phenyldithiocarbamate was used as the single source precursor. ► The growth temperature was varied to study the optical properties of the nanocrystals. ► Change in growth temperature affects the structural properties of the ZnS nanoparticles. ► Hexagonal wurtzite phase was obtained at lower temperatures while cubic sphalerite phase was obtained at higher growth temperatures. -- Abstract: Reported in this work is the synthesis of HDA (hexadecylamine)-capped ZnS nanoparticles by a single source route using Zinc(II) N-ethyl-N-phenyldithiocarbamate as a precursor. By varying the growth temperature, the temporal evolution of the optical properties and morphology of the nanocrystals were investigated. The as-synthesized nanoparticles were characterized using UV–vis absorption and photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). All the particles exhibited quantum confinement in their optical properties with band edge emission at the early stage of the reaction. The XRD showed transition from hexagonal wurtzite phase to cubic sphalerite phase as the growth temperature increases. The TEM image showed that the particles are small and spherical in shape while the HRTEM image confirmed the crystalline nature of the material.

SPECTRAL OPTICAL MONITORING OF THE NARROW-LINE SEYFERT 1 GALAXY Ark 564

International Nuclear Information System (INIS)

Shapovalova, A. I.; Burenkov, A. N.; Popović, L. Č.; Kovačević, J.; Chavushyan, V. H.; Valdes, J. R.; Torrealba, J.; Carrasco, L.; Ilić, D.; Kovačević, A.; Kollatschny, W.; Bochkarev, N. G.; León-Tavares, J.; Mercado, A.; Benítez, E.; Dultzin, D.; De la Fuente, E.

2012-01-01

We present the results of a long-term (1999-2010) spectral optical monitoring campaign of the active galactic nucleus (AGN) Ark 564, which shows a strong Fe II line emission in the optical. This AGN is a narrow-line Seyfert 1 (NLS1) galaxy, a group of AGNs with specific spectral characteristics. We analyze the light curves of the permitted Hα, Hβ, optical Fe II line fluxes, and the continuum flux in order to search for a time lag between them. Additionally, in order to estimate the contribution of iron lines from different multiplets, we fit the Hβ and Fe II lines with a sum of Gaussian components. We find that during the monitoring period the spectral variation (F max /F min ) of Ark 564 is between 1.5 for Hα and 1.8 for the Fe II lines. The correlation between the Fe II and Hβ flux variations is of higher significance than that of Hα and Hβ (whose correlation is almost absent). The permitted-line profiles are Lorentzian-like and do not change shape during the monitoring period. We investigate, in detail, the optical Fe II emission and find different degrees of correlation between the Fe II emission arising from different spectral multiplets and the continuum flux. The relatively weak and different degrees of correlations between permitted lines and continuum fluxes indicate a rather complex source of ionization of the broad-line emission region.

SPECTRAL OPTICAL MONITORING OF THE NARROW-LINE SEYFERT 1 GALAXY Ark 564

Energy Technology Data Exchange (ETDEWEB)

Shapovalova, A. I.; Burenkov, A. N. [Special Astrophysical Observatory of the Russian AS, Nizhnij Arkhyz, Karachaevo-Cherkesia 369167 (Russian Federation); Popovic, L. C.; Kovacevic, J. [Astronomical Observatory, Volgina 7, 11160 Belgrade 74 (Serbia); Chavushyan, V. H.; Valdes, J. R.; Torrealba, J.; Carrasco, L. [Instituto Nacional de Astrofisica, Optica y Electronica, Apartado Postal 51-216, 72000 Puebla (Mexico); Ilic, D.; Kovacevic, A. [Isaac Newton Institute of Chile, Yugoslavia Branch, Belgrade (Serbia); Kollatschny, W. [Institut fuer Astrophysik, Georg-August-Universitaet, Goettingen (Germany); Bochkarev, N. G. [Sternberg Astronomical Institute, Moscow (Russian Federation); Leon-Tavares, J. [Aalto University Metsaehovi Radio Observatory, Metsaehovintie 114, FIN-02540 Kylmaelae (Finland); Mercado, A. [Universidad Politecnica de Baja California, Av. de la Industria 291, 21010 Mexicali, B.C. (Mexico); Benitez, E.; Dultzin, D. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-264, Mexico, D.F. 04510 (Mexico); De la Fuente, E., E-mail: ashap@sao.ru [Instituto de Astronomia y Meteorologia, Dpto. de Fisica CUCEI, Universidad de Guadalajara, Av. Vallarta 2602, 44130 Guadalajara, Jalisco (Mexico)

2012-09-15

We present the results of a long-term (1999-2010) spectral optical monitoring campaign of the active galactic nucleus (AGN) Ark 564, which shows a strong Fe II line emission in the optical. This AGN is a narrow-line Seyfert 1 (NLS1) galaxy, a group of AGNs with specific spectral characteristics. We analyze the light curves of the permitted H{alpha}, H{beta}, optical Fe II line fluxes, and the continuum flux in order to search for a time lag between them. Additionally, in order to estimate the contribution of iron lines from different multiplets, we fit the H{beta} and Fe II lines with a sum of Gaussian components. We find that during the monitoring period the spectral variation (F{sub max}/F{sub min}) of Ark 564 is between 1.5 for H{alpha} and 1.8 for the Fe II lines. The correlation between the Fe II and H{beta} flux variations is of higher significance than that of H{alpha} and H{beta} (whose correlation is almost absent). The permitted-line profiles are Lorentzian-like and do not change shape during the monitoring period. We investigate, in detail, the optical Fe II emission and find different degrees of correlation between the Fe II emission arising from different spectral multiplets and the continuum flux. The relatively weak and different degrees of correlations between permitted lines and continuum fluxes indicate a rather complex source of ionization of the broad-line emission region.

Photorefractive response and optical damage of LiNbO3 optical waveguides produced by swift heavy ion irradiation

Science.gov (United States)

Villarroel, J.; Carrascosa, M.; García-Cabañes, A.; Caballero-Calero, O.; Crespillo, M.; Olivares, J.

2009-06-01

The photorefractive behaviour of a novel type of optical waveguides fabricated in LiNbO3 by swift heavy ion irradiation is investigated. First, the electro-optic coefficient r 33 of these guides that is crucial in the photorefractive effect is measured. Second, two complementary aspects of the photorefractive response are studied: (i) recording and light-induced and dark erasure of holographic gratings; (ii) optical beam degradation in single-beam configuration. The main photorefractive parameters, recording and erasing time constants, maximum refractive-index change and optical damage thresholds are determined.

Interferometer immunosensor based on porous silicon for determining alpha-fetoprotein

Science.gov (United States)

Lv, Xiaoyi; Jiang, Jing; Lv, Guodong; Mo, Jiaqing; Jia, Zhenhong

2016-10-01

An increased level of alpha-fetoprotein ( AFP) in the blood may be a sign of liver cancer. Porous silicon based optical microcavities structure is prepared as a label-free immunosensor platform for detecting AFP. After the antigen-antibody reaction, it is monitored that the red shift of the reflection spectrum of the immunosensor increases

Bose-Einstein condensation of paraxial light

Science.gov (United States)

Klaers, J.; Schmitt, J.; Damm, T.; Vewinger, F.; Weitz, M.

2011-10-01

Photons, due to the virtually vanishing photon-photon interaction, constitute to very good approximation an ideal Bose gas, but owing to the vanishing chemical potential a (free) photon gas does not show Bose-Einstein condensation. However, this is not necessarily true for a lower-dimensional photon gas. By means of a fluorescence induced thermalization process in an optical microcavity one can achieve a thermal photon gas with freely adjustable chemical potential. Experimentally, we have observed thermalization and subsequently Bose-Einstein condensation of the photon gas at room temperature. In this paper, we give a detailed description of the experiment, which is based on a dye-filled optical microcavity, acting as a white-wall box for photons. Thermalization is achieved in a photon number-conserving way by photon scattering off the dye molecules, and the cavity mirrors both provide an effective photon mass and a confining potential-key prerequisites for the Bose-Einstein condensation of photons. The experimental results are in good agreement with both a statistical and a simple rate equation model, describing the properties of the thermalized photon gas.

Incorporation of amphiphilic ruthenium(II) ammine complexes into Langmuir-Blodgett thin films with switchable quadratic nonlinear optical behavior.

Science.gov (United States)

Boubekeur-Lecaque, Leïla; Coe, Benjamin J; Harris, James A; Helliwell, Madeleine; Asselberghs, Inge; Clays, Koen; Foerier, Stijn; Verbiest, Thierry

2011-12-19

Nine nonlinear optical (NLO) chromophores with pyridinium electron acceptors have been synthesized by complexing new proligands with {Ru(II)(NH(3))(5)}(2+) electron-donor centers. The presence of long alkyl/fluoroalkyl chain substituents imparts amphiphilic properties, and these cationic complexes have been characterized as their PF(6)(-) salts by using various techniques including electronic absorption spectroscopy and cyclic voltammetry. Each complex shows three reversible/quasireversible redox processes; a Ru(III/II) oxidation and two ligand-based reductions. The energies of the intense visible d → π* metal-to-ligand charge-transfer (MLCT) absorptions correlate to some extent with the ligand reduction potentials. (1)H NMR spectroscopy also provides insights into the relative electron-withdrawing strengths of the new ligands. Single crystal X-ray structures have been determined for two of the proligand salts and one complex salt, [Ru(II)(NH(3))(5)(4-C(16)H(33)PhQ(+))]Cl(3)·3.25H(2)O (PhQ(+) = N-phenyl-4,4'-bipyridinium), showing centrosymmetric packing structures in each case. The PF(6)(-) analogue of the latter complex has been used to deposit reproducibly high-quality, multilayered Langmuir-Blodgett (LB) thin films. These films show a strong second harmonic generation (SHG) response from a 1064 nm laser; their MLCT absorbance increases linearly with the number of layers (N) and I(2ω)/I(ω)(2) (I(2ω) = intensity at 532 nm; I(ω) = intensity at 1064 nm) scales quadratically with N, consistent with homogeneous deposition. LB films on indium tin oxide (ITO)-coated glass show electrochemically induced switching of the SHG response, with a decrease in activity of about 50% on Ru(II) → Ru(III) oxidation. This effect is reversible, but reproducible over only a few cycles before the signal from the Ru(II) species diminishes. This work extrapolates our original solution studies (Coe, B. J. et al. Angew. Chem., Int. Ed.1999, 38, 366) to the first demonstration of

Reflective optics II; Proceedings of the Meeting, Orlando, FL, Mar. 27-29, 1989

International Nuclear Information System (INIS)

Korsch, D.G.

1989-01-01

Various papers on reflective optics are presented. Individual topics addressed include: measurement of the effect of particulate contamination on X-ray reflectivity; design optimization of astrometric reflectors; application of supersmooth optics to extrasolar planet detection; all-reflective spectrometer design of the Infrared Space Observatory; manufacturing the Keck 10-meter telescope structure and drives; advanced reflective optical systems for ground-based laboratory collimators; design of a catadioptric lens for long-range oblique aerial reconnaissance; development of a three-mirror, wide-field sensor; low-cost, lightweight, large-aperture laser transmitter/receiver; fabrication of the airborne optical adjunct mirrors; manufacturing simulation for precision optical fabrication of large mirrors; rapid optical fabrication technology for ultralightweight quartz-glass mirrors; cryogenic testing of reflective optical component and telescope systems

Reflective optics II; Proceedings of the Meeting, Orlando, FL, Mar. 27-29, 1989

Science.gov (United States)

Korsch, Dietrich G.

1989-10-01

Various papers on reflective optics are presented. Individual topics addressed include: measurement of the effect of particulate contamination on X-ray reflectivity; design optimization of astrometric reflectors; application of supersmooth optics to extrasolar planet detection; all-reflective spectrometer design of the Infrared Space Observatory; manufacturing the Keck 10-meter telescope structure and drives; advanced reflective optical systems for ground-based laboratory collimators; design of a catadioptric lens for long-range oblique aerial reconnaissance; development of a three-mirror, wide-field sensor; low-cost, lightweight, large-aperture laser transmitter/receiver; fabrication of the airborne optical adjunct mirrors; manufacturing simulation for precision optical fabrication of large mirrors; rapid optical fabrication technology for ultralightweight quartz-glass mirrors; cryogenic testing of reflective optical component and telescope systems.

A Practical Guide to Experimental Geometrical Optics

Science.gov (United States)

Garbovskiy, Yuriy A.; Glushchenko, Anatoliy V.

2017-12-01

Preface; 1. Markets of optical materials, components, accessories, light sources and detectors; 2. Introduction to optical experiments: light producing, light managing, light detection and measuring; 3. Light detectors based on semiconductors: photoresistors, photodiodes in a photo-galvanic regime. Principles of operation and measurements; 4. Linear light detectors based on photodiodes; 5. Basic laws of geometrical optics: experimental verification; 6. Converging and diverging thin lenses; 7. Thick lenses; 8. Lens systems; 9. Simple optical instruments I: the eye and the magnifier, eyepieces and telescopes; 10. Simple optical instruments II: light illuminators and microscope; 11. Spherical mirrors; 12. Introduction to optical aberrations; 13. Elements of optical radiometry; 14. Cylindrical lenses and vials; 15. Methods of geometrical optics to measure refractive index; 16. Dispersion of light and prism spectroscope; 17. Elements of computer aided optical design; Index.

Bioinspired Superhydrophobic Highly Transmissive Films for Optical Applications.

Science.gov (United States)

Vüllers, Felix; Gomard, Guillaume; Preinfalk, Jan B; Klampaftis, Efthymios; Worgull, Matthias; Richards, Bryce; Hölscher, Hendrik; Kavalenka, Maryna N

2016-11-01

Inspired by the transparent hair layer on water plants Salvinia and Pistia, superhydrophobic flexible thin films, applicable as transparent coatings for optoelectronic devices, are introduced. Thin polymeric nanofur films are fabricated using a highly scalable hot pulling technique, in which heated sandblasted steel plates are used to create a dense layer of nano- and microhairs surrounding microcavities on a polymer surface. The superhydrophobic nanofur surface exhibits water contact angles of 166 ± 6°, sliding angles below 6°, and is self-cleaning against various contaminants. Additionally, subjecting thin nanofur to argon plasma reverses its surface wettability to hydrophilic and underwater superoleophobic. Thin nanofur films are transparent and demonstrate reflection values of less than 4% for wavelengths ranging from 300 to 800 nm when attached to a polymer substrate. Moreover, used as translucent self-standing film, the nanofur exhibits transmission values above 85% and high forward scattering. The potential of thin nanofur films for extracting substrate modes from organic light emitting diodes is tested and a relative increase of the luminous efficacy of above 10% is observed. Finally, thin nanofur is optically coupled to a multicrystalline silicon solar cell, resulting in a relative gain of 5.8% in photogenerated current compared to a bare photovoltaic device. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Integrated photonics using colloidal quantum dots

Science.gov (United States)

Menon, Vinod M.; Husaini, Saima; Okoye, Nicky; Valappil, Nikesh V.

2009-11-01

Integrated photonic devices were realized using colloidal quantum dot composites such as flexible microcavity laser, microdisk emitters and integrated active-passive waveguides. The microcavity laser structure was realized using spin coating and consisted of an all-polymer distributed Bragg reflector with a poly-vinyl carbazole cavity layer embedded with InGaP/ZnS colloidal quantum dots. These microcavities can be peeled off the substrate yielding a flexible structure that can conform to any shape and whose emission spectra can be mechanically tuned. Planar photonic devices consisting of vertically coupled microring resonators, microdisk emitters, active-passive integrated waveguide structures and coupled active microdisk resonators were realized using soft lithography, photo-lithography, and electron beam lithography, respectively. The gain medium in all these devices was a composite consisting of quantum dots embedded in SU8 matrix. Finally, the effect of the host matrix on the optical properties of the quantum dots using results of steady-state and time-resolved luminescence measurements was determined. In addition to their specific functionalities, these novel device demonstrations and their development present a low-cost alternative to the traditional photonic device fabrication techniques.

THE RADIO AND OPTICAL LUMINOSITY EVOLUTION OF QUASARS. II. THE SDSS SAMPLE

International Nuclear Information System (INIS)

Singal, J.; Petrosian, V.; Stawarz, Ł.; Lawrence, A.

2013-01-01

We determine the radio and optical luminosity evolutions and the true distribution of the radio-loudness parameter R, defined as the ratio of the radio to optical luminosity, for a set of more than 5000 quasars combining Sloan Digital Sky Survey optical and Faint Images of the Radio Sky at Twenty cm (FIRST) radio data. We apply the method of Efron and Petrosian to access the intrinsic distribution parameters, taking into account the truncations and correlations inherent in the data. We find that the population exhibits strong positive evolution with redshift in both wavebands, with somewhat greater radio evolution than optical. With the luminosity evolutions accounted for, we determine the density evolutions and local radio and optical luminosity functions. The intrinsic distribution of the radio-loudness parameter R is found to be quite different from the observed one and is smooth with no evidence of a bimodality in radio loudness for log R ≥ –1. The results we find are in general agreement with the previous analysis of Singal et al., which used POSS-I optical and FIRST radio data.

Current status of three-dimensional silicon photonic crystals operating at infrared wavelengths

Energy Technology Data Exchange (ETDEWEB)

LIN,SHAWN-YU; FLEMING,JAMES G.; SIGALAS,M.M.; BISWAS,R.; HO,K.M.

2000-05-11

In this paper, the experimental realization and promises of three-dimensional (3D) photonic crystals in the infrared and optical wavelengths will be described. Emphasis will be placed on the development of new 3D photonic crystals, the micro- and nano-fabrication techniques, the construction of high-Q micro-cavities and the creation of 3D waveguides.

An extreme Fe II emitter the narrow line quasar PHL 1092

CERN Document Server

Bergeron, J

1980-01-01

A search for Fe II emission in a sample of radio-quiet quasars has revealed the outstanding properties of PHL 1092. Intense Fe II lines dominate the entire spectrum, and the Fe II UV multiplets are nearly as strong as the optical ones. In contrast the extreme weakness of the Balmer and Mg II lines is striking. For the first time, Fe I lines are identified in an extra-galactic object. The lines are narrow, with a FWHM of 1300 km s/sup -1/. The presence of Fe II UV lines and Fe I lines from the ground state requires moderate column densities. However Fe/sup 0/ can exist only in a region completely shielded from the UV continuum. The weakness of Mg II and H beta relative to Fe II lines is best explained by their thermalization. The emitting region is of high electron density n/sub e/ approximately=10/sup 12/ cm/sup -3/, low temperature T approximately=10000K, and has an optical depth in the Fe II UV lines tau /sub UV/ approximately=10/sup 3/-10/sup 4/. It is speculated that for higher densities all the lines wou...

Low-SNR Capacity of Parallel IM-DD Optical Wireless Channels

KAUST Repository

Chaaban, Anas

2016-11-29

The capacity of parallel intensity-modulation and direct-detection (IM-DD) optical wireless channels with total average intensity and per-channel peak intensity constraints is studied. The optimal intensity allocation at low signal-to-noise ratio (SNR) is derived, leading to the capacity-achieving onoff keying (OOK) distribution. Interestingly, while activating the strongest channel is optimal if (i) the peak intensity is fixed, this is not the case if (ii) the peak intensity is proportional to the average intensity. The minimum average optical intensity per bit is also studied, and is characterized for case (i) where it is achievable at low SNR. However, in case (ii), the average optical intensity per bit grows indefinitely as SNR decreases, indicating that lower optical intensity per bit can be achieved at moderate SNR than at low SNR.

Synthesis, crystal structure and growth of a new inorganic- organic hybrid compound for nonlinear optical applications: Aquadiiodo (3-aminopropanoic acid) cadmium (II)

Science.gov (United States)

Boopathi, K.; Babu, S. Moorthy; Jagan, R.; Ramasamy, P.

2017-12-01

The new inorganic-organic hybrid material aquadiiodo (3-aminopropanoic acid) cadmium (II) [ADI (3-AP) Cd] has been successfully synthesized and good quality crystals have been grown by slow evaporation solution technique. The structure was determined by single crystal X-ray diffraction at room temperature. The compound crystallizes in monoclinic crystal system with centro symmetric space group P21/c and four molecules in the unit cell. The structure of the title compound was further confirmed by 1H and 13C nuclear magnetic resonance spectral analysis. FT-IR spectroscopy was used to confirm the presence of various functional groups in the compound. The transmittance and optical parameters of the crystal were studied by UV- Visible-NIR spectroscopy. The thermal stability of the grown crystal was evaluated using thermogravimetric and differential thermal analyses. Mechanical hardness has been identified by Vickers micro hardness study and work hardening coefficient was calculated. Dielectric measurement was carried out as a function of frequency and results are discussed. The growth mechanism of the crystal was assessed by chemical etching studies. The third-order nonlinear optical susceptibility of [ADI (3-AP) Cd] was derived using the Z-scan technique, and it was 3.24955 × 10-8 esu. The positive nonlinear refractive index 2.48505 × 10-11 m2/W, is an indication of self-defocusing optical nonlinearity of the sample. It is believed that the [ADI (3-AP) Cd] is a promising new candidate for developing efficient nonlinear optical and optical power limiting devices.

Chemically modified activated carbon with 1-acylthiosemicarbazide for selective solid-phase extraction and preconcentration of trace Cu(II), Hg(II) and Pb(II) from water samples.

Science.gov (United States)

Gao, Ru; Hu, Zheng; Chang, Xijun; He, Qun; Zhang, Lijun; Tu, Zhifeng; Shi, Jianping

2009-12-15

A new sorbent 1-acylthiosemicarbazide-modified activated carbon (AC-ATSC) was prepared as a solid-phase extractant and applied for removing of trace Cu(II), Hg(II) and Pb(II) prior to their determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The separation/preconcentration conditions of analytes were investigated, including effects of pH, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. At pH 3, the maximum static adsorption capacity of Cu(II), Hg(II) and Pb(II) onto the AC-ATSC were 78.20, 67.80 and 48.56 mg g(-1), respectively. The adsorbed metal ions were quantitatively eluted by 3.0 mL of 2% CS(NH2)2 and 2.0 mol L(-1) HCl solution. Common coexisting ions did not interfere with the separation. According to the definition of IUPAC, the detection limits (3sigma) of this method for Cu(II), Hg(II) and Pb(II) were 0.20, 0.12 and 0.45 ng mL(-1), respectively. The relative standard deviation under optimum conditions is less than 4.0% (n=8). The prepared sorbent was applied for the preconcentration of trace Cu(II), Hg(II) and Pb(II) in certified and water samples with satisfactory results.

Code division multiple-access techniques in optical fiber networks. II - Systems performance analysis

Science.gov (United States)

Salehi, Jawad A.; Brackett, Charles A.

1989-08-01

A technique based on optical orthogonal codes was presented by Salehi (1989) to establish a fiber-optic code-division multiple-access (FO-CDMA) communications system. The results are used to derive the bit error rate of the proposed FO-CDMA system as a function of data rate, code length, code weight, number of users, and receiver threshold. The performance characteristics for a variety of system parameters are discussed. A means of reducing the effective multiple-access interference signal by placing an optical hard-limiter at the front end of the desired optical correlator is presented. Performance calculations are shown for the FO-CDMA with an ideal optical hard-limiter, and it is shown that using a optical hard-limiter would, in general, improve system performance.

Virtual Accelerator for Accelerator Optics Improvement

CERN Document Server

Yan Yi Ton; Decker, Franz Josef; Ecklund, Stanley; Irwin, John; Seeman, John; Sullivan, Michael K; Turner, J L; Wienands, Ulrich

2005-01-01

Through determination of all quadrupole strengths and sextupole feed-downs by fitting quantities derivable from precision orbit measurement, one can establish a virtual accelerator that matches the real accelerator optics. These quantities (the phase advances, the Green's functions, and the coupling eigen-plane ellipses tilt angles and axis ratios) are obtained by analyzing turn-by-turn Beam Position Monitor (BPM) data with a model-independent analysis (MIA). Instead of trying to identify magnet errors, a limited number of quadrupoles are chosen for optimized strength adjustment to improve the virtual accelerator optics and then applied to the real accelerator accordingly. These processes have been successfully applied to PEP-II rings for beta beating fixes, phase and working tune adjustments, and linear coupling reduction to improve PEP-II luminosity.

A novel optical gating method for laser gated imaging

Science.gov (United States)

Ginat, Ran; Schneider, Ron; Zohar, Eyal; Nesher, Ofer

2013-06-01

For the past 15 years, Elbit Systems is developing time-resolved active laser-gated imaging (LGI) systems for various applications. Traditional LGI systems are based on high sensitive gated sensors, synchronized to pulsed laser sources. Elbit propriety multi-pulse per frame method, which is being implemented in LGI systems, improves significantly the imaging quality. A significant characteristic of the LGI is its ability to penetrate a disturbing media, such as rain, haze and some fog types. Current LGI systems are based on image intensifier (II) sensors, limiting the system in spectral response, image quality, reliability and cost. A novel propriety optical gating module was developed in Elbit, untying the dependency of LGI system on II. The optical gating module is not bounded to the radiance wavelength and positioned between the system optics and the sensor. This optical gating method supports the use of conventional solid state sensors. By selecting the appropriate solid state sensor, the new LGI systems can operate at any desired wavelength. In this paper we present the new gating method characteristics, performance and its advantages over the II gating method. The use of the gated imaging systems is described in a variety of applications, including results from latest field experiments.

Whispering-gallery mode microcavity quantum-dot lasers

International Nuclear Information System (INIS)

Kryzhanovskaya, N V; Maximov, M V; Zhukov, A E

2014-01-01

This review examines axisymmetric-cavity quantum-dot microlasers whose emission spectrum is determined by whisperinggallery modes. We describe the possible designs, fabrication processes and basic characteristics of the microlasers and demonstrate the possibility of lasing at temperatures above 100 °C. The feasibility of creating multichannel optical sources based on a combination of a broadband quantum-dot laser and silicon microring modulators is discussed. (review)

Light Weight, Scalable Manufacturing of Telescope Optics, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — NASA's future X-ray astronomy missions will require X-ray optics that have large effective areas, are lightweight, and cost effective. Recent X-ray telescopes, such...

Nocturnal insects use optic flow for flight control.

Science.gov (United States)

Baird, Emily; Kreiss, Eva; Wcislo, William; Warrant, Eric; Dacke, Marie

2011-08-23

To avoid collisions when navigating through cluttered environments, flying insects must control their flight so that their sensory systems have time to detect obstacles and avoid them. To do this, day-active insects rely primarily on the pattern of apparent motion generated on the retina during flight (optic flow). However, many flying insects are active at night, when obtaining reliable visual information for flight control presents much more of a challenge. To assess whether nocturnal flying insects also rely on optic flow cues to control flight in dim light, we recorded flights of the nocturnal neotropical sweat bee, Megalopta genalis, flying along an experimental tunnel when: (i) the visual texture on each wall generated strong horizontal (front-to-back) optic flow cues, (ii) the texture on only one wall generated these cues, and (iii) horizontal optic flow cues were removed from both walls. We find that Megalopta increase their groundspeed when horizontal motion cues in the tunnel are reduced (conditions (ii) and (iii)). However, differences in the amount of horizontal optic flow on each wall of the tunnel (condition (ii)) do not affect the centred position of the bee within the flight tunnel. To better understand the behavioural response of Megalopta, we repeated the experiments on day-active bumble-bees (Bombus terrestris). Overall, our findings demonstrate that despite the limitations imposed by dim light, Megalopta-like their day-active relatives-rely heavily on vision to control flight, but that they use visual cues in a different manner from diurnal insects. This journal is © 2011 The Royal Society

ICC Type II large-format FPA detector assemblies

Science.gov (United States)

Clynne, Thomas H.; Powers, Thomas P.

1997-08-01

ICC presents a new addition to their integrated detector assembly product line with the announcement of their type II large format staring class FPA units. A result of internally funded research and development, the ICC type II detector assembly can accommodate all existing large format staring class PtSi, InSb and MCT focal planes, up to 640 by 480. Proprietary methodologies completely eliminate all FPA stresses to allow for maximum FPA survivability. Standard optical and cryocooler interfaces allow for the use of BEI, AEG, TI SADA Hughes/Magnavox and Joule Thompson coolers. This unit has been qualified to the current SADA II thermal environmental specifications and was tailored around ICC's worldwide industry standard type IV product. Assembled in a real world flexible manufacturing environment, this unit features a wide degree of adaptability and can be easily modified to a user's specifications via standard options and add-ons that include optical interfaces, electrical interfaces and window/filter material selections.

Type II Supernova Light Curves and Spectra from the CfA

Science.gov (United States)

Hicken, Malcolm; Friedman, Andrew S.; Blondin, Stephane; Challis, Peter; Berlind, Perry; Calkins, Mike; Esquerdo, Gil; Matheson, Thomas; Modjaz, Maryam; Rest, Armin; Kirshner, Robert P.

2017-11-01

We present multiband photometry of 60 spectroscopically confirmed supernovae (SNe): 39 SNe II/IIP, 19 IIn, 1 IIb, and 1 that was originally classified as a IIn but later as a Ibn. Of these, 46 have only optical photometry, 6 have only near-infrared (NIR) photometry, and 8 have both optical and NIR. The median redshift of the sample is 0.016. We also present 195 optical spectra for 48 of the 60 SN. There are 26 optical and 2 NIR light curves of SNe II/IIP with redshifts z> 0.01, some of which may give rise to useful distances for cosmological applications. All photometry was obtained between 2000 and 2011 at the Fred Lawrence Whipple Observatory (FLWO), via the 1.2 m and 1.3 m PAIRITEL telescopes for the optical and NIR, respectively. Each SN was observed in a subset of the u\\prime {UBVRIr}\\prime I\\prime {{JHK}}s bands. There are a total of 2932 optical and 816 NIR light curve points. Optical spectra were obtained using the FLWO 1.5 m Tillinghast telescope with the FAST spectrograph and the MMT Telescope with the Blue Channel Spectrograph. Our photometry is in reasonable agreement with select samples from the literature: two-thirds of our star sequences have average V offsets within ±0.02 mag and roughly three-quarters of our light curves have average differences within ±0.04 mag. The data from this work and the literature will provide insight into SN II explosions, help with developing methods for photometric SN classification, and contribute to their use as cosmological distance indicators.

Bose-Einstein condensation of photons in an optical microcavity

OpenAIRE

Klaers, Jan; Schmitt, Julian; Vewinger, Frank; Weitz, Martin

2010-01-01

Bose-Einstein condensation, the macroscopic ground state accumulation of particles with integer spin (bosons) at low temperature and high density, has been observed in several physical systems, including cold atomic gases and solid state physics quasiparticles. However, the most omnipresent Bose gas, blackbody radiation (radiation in thermal equilibrium with the cavity walls) does not show this phase transition, because the chemical potential of photons vanishes and, when the temperature is r...

Bose-Einstein condensation of light: general theory.

Science.gov (United States)

Sob'yanin, Denis Nikolaevich

2013-08-01

A theory of Bose-Einstein condensation of light in a dye-filled optical microcavity is presented. The theory is based on the hierarchical maximum entropy principle and allows one to investigate the fluctuating behavior of the photon gas in the microcavity for all numbers of photons, dye molecules, and excitations at all temperatures, including the whole critical region. The master equation describing the interaction between photons and dye molecules in the microcavity is derived and the equivalence between the hierarchical maximum entropy principle and the master equation approach is shown. The cases of a fixed mean total photon number and a fixed total excitation number are considered, and a much sharper, nonparabolic onset of a macroscopic Bose-Einstein condensation of light in the latter case is demonstrated. The theory does not use the grand canonical approximation, takes into account the photon polarization degeneracy, and exactly describes the microscopic, mesoscopic, and macroscopic Bose-Einstein condensation of light. Under certain conditions, it predicts sub-Poissonian statistics of the photon condensate and the polarized photon condensate, and a universal relation takes place between the degrees of second-order coherence for these condensates. In the macroscopic case, there appear a sharp jump in the degrees of second-order coherence, a sharp jump and kink in the reduced standard deviations of the fluctuating numbers of photons in the polarized and whole condensates, and a sharp peak, a cusp, of the Mandel parameter for the whole condensate in the critical region. The possibility of nonclassical light generation in the microcavity with the photon Bose-Einstein condensate is predicted.

Space Density Of Optically-Selected Type II Quasars From The SDSS

Science.gov (United States)

Reyes, Reinabelle; Zakamska, N. L.; Strauss, M. A.; Green, J.; Krolik, J. H.; Shen, Y.; Richards, G. T.

2007-12-01

Type II quasars are luminous Active Galactic Nuclei (AGN) whose central regions are obscured by large amounts of gas and dust. In this poster, we present a catalog of 887 type II quasars with redshifts z<0.83 from the Sloan Digital Sky Survey (SDSS), selected based on their emission lines, and derive the 1/Vmax [OIII] 5007 luminosity function from this sample. Since some objects may not be included in the sample because they lack strong emission lines, the derived luminosity function is only a lower limit. We also derive the [OIII] 5007 luminosity function for a sample of type I (broad-line) quasars in the same redshift range. Taking [OIII] 5007 luminosity as a tracer of intrinsic luminosity in both type I and type II quasars, we obtain lower limits to the type II quasar fraction as a function of [OIII] 5007 luminosity, from L[OIII] = 108.3 to 1010 Lsun, which roughly correspond to bolometric luminosities of 1044 to 1046 erg/s.

Radiative parameters for some transitions in Cu(II) and Ag(II) spectrum

International Nuclear Information System (INIS)

Biemont, E.; Blagoev, K.; Campos, J.; Mayo, R.; Malcheva, G.; Ortiz, M.; Quinet, P.

2005-01-01

Radiative parameters for transitions depopulating the levels belonging to the 3d 8 4s 2 configuration of Cu(II) and 4d 9 6s and 4d 9 5d configurations of Ag(II) have been obtained both theoretically and experimentally. On the experimental side, a laser-produced plasma was used as a source of Cu(II) and Ag(II) spectra. The light emitted by the plasma was focused on the input slit of a grating monochromator coupled with a time-resolved optical multichannel analyzer system. Spectral response calibration of the experimental system was made using a deuterium lamp in the wavelength range extending from 200 to 400-bar nm, and a standard tungsten lamp in the range from 350 to 600-bar nm. The transition probabilities were obtained using measured branching fractions and available radiative lifetimes of the corresponding states. On the theoretical side, a relativistic Hartree-Fock (HFR) approach, including core-polarization effects, has been used for the calculations. A reasonable agreement theory-experiment has been observed

A SUBSTELLAR COMMON PROPER-MOTION COMPANION TO THE PLEIAD H II 1348

International Nuclear Information System (INIS)

Geißler, Kerstin; Metchev, Stanimir A.; Pham, Alfonse; Larkin, James E.; McElwain, Michael; Hillenbrand, Lynne A.

2012-01-01

We announce the identification of a proper-motion companion to the star H II 1348, a K5 V member of the Pleiades open cluster. The existence of a faint point source 1.''1 away from H II 1348 was previously known from adaptive optics imaging by Bouvier et al. However, because of a high likelihood of background star contamination and in the absence of follow-up astrometry, Bouvier et al. tentatively concluded that the candidate companion was not physically associated with H II 1348. We establish the proper-motion association of the pair from adaptive optics imaging with the Palomar 5 m telescope. Adaptive optics spectroscopy with the integral field spectrograph OSIRIS on the Keck 10 m telescope reveals that the companion has a spectral type of M8 ± 1. According to substellar evolution models, the M8 spectral type resides within the substellar mass regime at the age of the Pleiades. The primary itself is a known double-lined spectroscopic binary, which makes the resolved companion, H II 1348B, the least massive and widest component of this hierarchical triple system and the first substellar companion to a stellar primary in the Pleiades.

DUMAND-II progress report

International Nuclear Information System (INIS)

Wilkes, R.J.; Alexander, C.M.; Aoki, T.; Berson, U.; Bosetti, P.; Bolesta, J.; Boynton, P.E.; Bradner, H.; Camerini, U.; Dye, S.T.; Gergin, E.; Gorham, P.W.; Grieder, P.K.F.; Grogan, W.; Hanada, H.; Harris, D.; Hayashino, T.; Hazen, E.; Ito, M.; Jaworski, M.; Jenko, M.; Kawamoto, H.; Kitamura, T.; Kobayakawa, K.; Kondo, S.; Koske, P.; Learned, J.G.; Ley, C.; Lord, J.J.; Lord, R.; Lozic, T.; March, R.; Matsumoto, T.; Matsuno, S.; Mavretic, A.; McCourry, L.; Mignard, M.; Miller, K.; Minkowski, P.; Mitiguy, R.; Mitsui, K.; Narita, S.; Nicklaus, D.

1993-01-01

The design, scientific goals, and capabilities of the DUMAND II detector system are described. Construction was authorized by DOE in 1990, and construction of various detector subsystems is under way. Current plans include deployment of the shore cable, junction box and three strings of optical detector modules in 1993, with expansion to the full 9-string configuration about one year later

Structural changes of the macula and optic nerve head in the remaining eyes after enucleation for retinoblastoma: an optical coherence tomography study.

Science.gov (United States)

Said, Azza Mohamed Ahmed; Elbayomi, Ahmed Mohamed; Shaat, Ashraf Abdelsalam Kandeel

2017-12-16

To describe objectively the possible structural changes of the macula and optic nerve head in the free eyes of unilateral cured retinoblastoma patients and, also after enucleation using spectral domain optical coherence tomography. A cross sectional study involving 60 patients subdivided into three groups; 15 unilateral RB patients in whom enucleation was indicated as a sole treatment performed earlier in life [(study group (I)], 15 unilateral RB patients who had completely regressed disease with a preserved eye [(study group (II)] and 30 age and sex matched healthy controls. The remaining and free eyes in study groups and right eyes of control group had full ophthalmological examination, static automated perimetry and optical coherence tomography of the macula and optic nerve head. In study group (II); a significant thinning of total macula, central fovea, ganglion cell layer (GCL), ganglion cell complex (GCC), and some sectors of outer nuclear layer (P- values ≤0.05) was found with no significant difference in peripapillary nerve fiber layer (pRNFL) thickness and optic nerve head parameters compared to the control group and the study group (I). A significantly thickened total macula, GCL, GCC, and pRNFL in study group (I) compared to study group (II). Thickened pRNFL was significantly correlated to standard automated perimetry pattern deviations. No significant difference was found between study group (I) and control group. Retinoblastoma eyes characterized by thinning of central fovea, GCL, GCC compared to the control group. After unilateral enucleation, increased GCC and pRNFL thicknesses were detected compared to retinoblastoma group.

Bose-Einstein Condensation of Long-Lifetime Polaritons in Thermal Equilibrium.

Science.gov (United States)

Sun, Yongbao; Wen, Patrick; Yoon, Yoseob; Liu, Gangqiang; Steger, Mark; Pfeiffer, Loren N; West, Ken; Snoke, David W; Nelson, Keith A

2017-01-06

The experimental realization of Bose-Einstein condensation (BEC) with atoms and quasiparticles has triggered wide exploration of macroscopic quantum effects. Microcavity polaritons are of particular interest because quantum phenomena such as BEC and superfluidity can be observed at elevated temperatures. However, polariton lifetimes are typically too short to permit thermal equilibration. This has led to debate about whether polariton condensation is intrinsically a nonequilibrium effect. Here we report the first unambiguous observation of BEC of optically trapped polaritons in thermal equilibrium in a high-Q microcavity, evidenced by equilibrium Bose-Einstein distributions over broad ranges of polariton densities and bath temperatures. With thermal equilibrium established, we verify that polariton condensation is a phase transition with a well-defined density-temperature phase diagram. The measured phase boundary agrees well with the predictions of basic quantum gas theory.

Extinction of H II regions

International Nuclear Information System (INIS)

Israel, F.P.; Kennicutt, R.C.

1980-01-01

Visual extinction of H II regions in nine nearby galaxies as derived from the ratio of the radio continuum emission to H-alpha emission is systematically larger than visual extinction deduced from the Balmer lines alone, if one assumes a value Av/E(B-V) 3. An optically-limited sample of about 30 extragalactic H II regions has a mean extinction of 1.7 m in the visual while about 1.2 m is not seen in the reddening of the Balmer lines. Both reddening and extinction decreases with increasing galactic radius, at least for M33 and M101

Coupling fiber optics to a permeation liquid membrane for heavy metal sensor development.

Science.gov (United States)

Ueberfeld, Jörn; Parthasarathy, Nalini; Zbinden, Hugo; Gisin, Nicolas; Buffle, Jacques

2002-02-01

We present the first sensing system for metal ions based on the combination of separation/preconcentration by a permeation liquid membrane (PLM) and fluorescence detection with an optical fiber. As a model, a system for the detection of Cu(II) ions was developed. The wall of a polypropylene hollow fiber serves as support for the permeable liquid membrane. The lumen of the fiber contains the strip solution in which Cu(II) is accumulated. Calcein, a fluorochromic dye, acts as stripping agent and at the same time as metal indicator. The quenching of the calcein fluorescence upon metal accumulation in the strip phase is detected with a multimode optical fiber, which is incorporated into the lumen. Fluorescence is excited with a blue LED and detected with a photon counter. Taking advantage of the high selectivity and sensitivity of PLM preconcentration, a detection limit for Cu(II) of approximately 50 nM was achieved. Among five tested heavy metal ions, Pb(II) was the only major interfering species. The incorporation of small silica optical fibers into the polypropylene capillary allows for real-time monitoring of the Cu(II) accumulation process.

Practical system for the generation of pulsed quantum frequency combs.

Science.gov (United States)

Roztocki, Piotr; Kues, Michael; Reimer, Christian; Wetzel, Benjamin; Sciara, Stefania; Zhang, Yanbing; Cino, Alfonso; Little, Brent E; Chu, Sai T; Moss, David J; Morandotti, Roberto

2017-08-07

The on-chip generation of large and complex optical quantum states will enable low-cost and accessible advances for quantum technologies, such as secure communications and quantum computation. Integrated frequency combs are on-chip light sources with a broad spectrum of evenly-spaced frequency modes, commonly generated by four-wave mixing in optically-excited nonlinear micro-cavities, whose recent use for quantum state generation has provided a solution for scalable and multi-mode quantum light sources. Pulsed quantum frequency combs are of particular interest, since they allow the generation of single-frequency-mode photons, required for scaling state complexity towards, e.g., multi-photon states, and for quantum information applications. However, generation schemes for such pulsed combs have, to date, relied on micro-cavity excitation via lasers external to the sources, being neither versatile nor power-efficient, and impractical for scalable realizations of quantum technologies. Here, we introduce an actively-modulated, nested-cavity configuration that exploits the resonance pass-band characteristic of the micro-cavity to enable a mode-locked and energy-efficient excitation. We demonstrate that the scheme allows the generation of high-purity photons at large coincidence-to-accidental ratios (CAR). Furthermore, by increasing the repetition rate of the excitation field via harmonic mode-locking (i.e. driving the cavity modulation at harmonics of the fundamental repetition rate), we managed to increase the pair production rates (i.e. source efficiency), while maintaining a high CAR and photon purity. Our approach represents a significant step towards the realization of fully on-chip, stable, and versatile sources of pulsed quantum frequency combs, crucial for the development of accessible quantum technologies.

Variability of Fe II Emission Features in the Seyfert 1 Galaxy NGC 5548

DEFF Research Database (Denmark)

Vestergaard, Marianne; Peterson, B. M.

2005-01-01

We study the low-contrast Fe II emission blends in the ultraviolet (1250--2200A) and optical (4000--6000A) spectra of the Seyfert 1 galaxy NGC 5548 and show that these features vary in flux and that these variations are correlated with those of the optical continuum. The amplitude of variability ...... are correlated indicates that line fluorescence in a photoionized plasma, rather than collisional excitation, is responsible for the Fe II emission. The iron emission templates are available upon request....

OPALS: A COTS-based Tech Demo of Optical Communications

Science.gov (United States)

Oaida, Bogdan

2012-01-01

I. Objective: Deliver video from ISS to optical ground terminal via an optical communications link. a) JPL Phaeton/Early Career Hire (ECH) training project. b) Implemented as Class-D payload. c) Downlink at approx.30Mb/s. II. Flight System a) Optical Head Beacon Acquisition Camera. Downlink Transmitter. 2-axis Gimbal. b) Sealed Container Laser Avionics Power distribution Digital I/O board III. Implementation: a) Ground Station - Optical Communications Telescope Laboratory at Table Mountain Facility b) Flight System mounted to ISS FRAM as standard I/F. Attached externally on Express Logistics Carrier.

Novel optics for conditioning neutron beams. II Focussing neutrons with a 'lobster-eye' optic

International Nuclear Information System (INIS)

Allman, B.E.; Cimmino, A.; Griffin, S.L.; Klein, A.G.; Nugent, K.A.

1998-01-01

Square-channel capillary, or 'Lobster-eye' arrays have been shown to be the optimum geometry for array optics. This configuration leads to a novel class of conditioning devices for X-ray and neutron beams. We present the first results of the focussing of neutrons with a Pb glass square-channel array. (authors)

Time-Resolved Transient Optical Absorption Study of Bis(terpyridyl)oligothiophenes and Their Metallo-Supramolecular Polymers with Zn(II) Ion Couplers.

Science.gov (United States)

Rais, David; Menšík, Miroslav; Štenclová-Bláhová, Pavla; Svoboda, Jan; Vohlídal, Jiří; Pfleger, Jiří

2015-06-18

α,ω-Bis(terpyridyl)oligothiophenes spontaneously assemble with Zn(II) ions giving conjugated constitutional dynamic polymers (dynamers) of the metallo-supramolecular class, which potentially might be utilized in optoelectronics. Their photophysical properties, which are of great importance in this field of application, are strongly influenced by the dynamic morphology. It was assessed in this study by using ultrafast pump-probe optical absorption spectroscopy. We identified and characterized relaxation processes running in photoexcited molecules of these oligomers and dynamers and show impacts of disturbed coplanarity of adjacent rings (twisting the thiophene-thiophene and thiophene-terpyridyl bonds by attached hexyl side groups) and Zn(II) ion couplers on these processes. Major effects are seen in the time constants of rotational relaxation, intersystem crossing, and de-excitation lifetimes. The photoexcited states formed on different repeating units within the same dynamer chain do not interact with each other even at very high excitation density. The method is presented that allows determining the equilibrium fraction of unbound oligothiophene species in a dynamer solution, from which otherwise hardly accessible values of the average degree of polymerization of constitutionally dynamic chains in solution can be estimated.

Review on technology II

International Nuclear Information System (INIS)

Mroziewicz, B.

1986-01-01

The most important requirements for the spectral properties of photodetectors are reviewed with particular attention to the fiber optics applications. Data on a number of materials are collected and presented. Pros and cons are pointed out for each type of photodetector-photoconductor, p-i-n photodiode and APD. A review is given of the relevant papers presented in the poster session 'Technology II' of the Symposium

SAGE II measurements of early Pinatubo aerosols

Science.gov (United States)

Mccormick, M. P.; Veiga, R. E.

1992-01-01

SAGE II satellite measurements of the Mt. Pinatubo eruption cloud in the stratosphere during June, July, and early August 1991 show that aerosols in the tropics reached as high as 29 km altitude with most of the cloud between 20 and 25 km. The most optically thick portions of the cloud covered latitudes from 10 deg S to 30 deg N during the early part of this period. By late July, high stratospheric optical depths were observed to at least 70 deg N, with the high values north of about 30 deg N from layers below 20 km. High pressure systems in both hemispheres were observed to be correlated with the movement of volcanic material at 21 km into the westerly jet stream at high southern latitudes and similarly to high northern latitudes at 16 km. By August, the entire Southern Hemisphere had experienced a 10-fold increase in optical depth relative to early July due to layers above 20 km. Initial mass calculations using SAGE II data place the aerosol produced from this eruption at 20 to 30 megatons, well above the 12 megatons produced by El Chichon.

Mononuclear, trinuclear, and hetero-trinuclear supramolecular complexes containing a new tri-sulfonate ligand and cobalt(II)/copper(II)-(1,10-phenanthroline) 2 building blocks

Science.gov (United States)

Yu, Yunfang; Wei, Yongqin; Broer, Ria; Sa, Rongjian; Wu, Kechen

2008-03-01

Novel mononuclear, trinuclear, and hetero-trinuclear supermolecular complexes, [Co(phen) 2(H 2O)(HTST)]·2H 2O ( 1), [Co 3(phen) 6(H 2O) 2(TST) 2]·7H 2O ( 2), and [Co 2Cu(phen) 6(H 2O) 2(TST) 2]·10H 2O ( 3), have been synthesized by the reactions of a new tri-sulfonate ligand (2,4,6-tris(4-sulfophenylamino)-1,3,5-triazine, H 3TST) with the M2+ ( M=Co, Cu) and the second ligand 1,10-phenanthroline (phen). Complex 1 contains a cis-Co(II)(phen) 2 building block and an HTST as monodentate ligand; complex 2 consists of two TST as bidentate ligands connecting one trans- and two cis-Co(II)(phen) 2 building blocks; complex 3 is formed by replacing the trans-Co(II)(phen) 2 in 2 with a trans-Cu(II)(phen) 2, which is the first reported hetero-trinuclear supramolecular complex containing both the Co(II)(phen) 2 and Cu(II)(phen) 2 as building blocks. The study shows the flexible multifunctional self-assembly capability of the H 3TST ligands presenting in these supramolecular complexes through coordinative, H-bonding and even π- π stacking interactions. The photoluminescent optical properties of these complexes are also investigated and discussed as well as the second-order nonlinear optical properties of 1.

Fiber Optic Temperature Sensors for Thermal Protection Systems, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — In Phase 1, Intelligent Fiber Optic Systems Corporation (IFOS), in collaboration with North Carolina State University, successfully demonstrated a Fiber Bragg...

Sixth International Workshop on Laser Physics (LPHYS 97) Volume 8, No. 1

Science.gov (United States)

1998-01-01

Microcavity Trap F. De Martini, O. Jedrkiewicz, and P. Mataloni Dipartimento di Fisica , Universita di Roma "La Sapienza," Istituto Nationale di...Fizica, Instituto Venezolano de Investigaciones Cientificas, Apartado 21827, Caracas 1020 A, Venezuela e-mail: yukalov@solids.iccmp.br Received August...Optics, Garching, Germany Herbert .Walther @ mpq. mpg. de Douwe A. Wiersma University of Groningen, Groningen, The Netherlands wiersma@chem.rug.nl

Basic and applied research at NTT and postgraduate education

International Nuclear Information System (INIS)

Kimura, Tatsuya

1995-01-01

Several current research topics, which are studied at NTT Basic Research Laboratories, are reviewed in the fields of semiconductor physics, quantum optics and biophysics. These topics include the surface structure transition of GaAs, InAs and Si, electron transport in low-dimensional structure, microcavity quantum-wire semiconductor lasers, quantum nondemolition measurement of fibre solitons, and artificial network development of cultivated neural cells. 32 refs., 33 fig

Pulsed laser deposited amorphous chalcogenide and alumino-silicate thin films and their multilayered structures for photonic applications

Energy Technology Data Exchange (ETDEWEB)

Němec, P. [Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice (Czech Republic); Charrier, J. [FOTON, UMR CNRS 6082, Enssat, 6 rue de Kerampont, BP 80518, 22305 Lannion (France); Cathelinaud, M. [Missions des Ressources et Compétences Technologiques, UPS CNRS 2274, 92195 Meudon (France); Allix, M. [CEMHTI-CNRS, Site Haute Température, Orléans (France); Adam, J.-L.; Zhang, S. [Equipe Verres et Céramiques, UMR-CNRS 6226, Sciences Chimiques de Rennes (SCR), Université de Rennes 1, 35042 Rennes Cedex (France); Nazabal, V., E-mail: virginie.nazabal@univ-rennes1.fr [Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice (Czech Republic); Equipe Verres et Céramiques, UMR-CNRS 6226, Sciences Chimiques de Rennes (SCR), Université de Rennes 1, 35042 Rennes Cedex (France)

2013-07-31

Amorphous chalcogenide and alumino-silicate thin films were fabricated by the pulsed laser deposition technique. Prepared films were characterized in terms of their morphology, chemical composition, and optical properties. Multilayered thin film stacks for reflectors and vertical microcavities were designed for telecommunication wavelength and the window of atmosphere transparency (band II) at 1.54 μm and 4.65 μm, respectively. Bearing in mind the benefit coming from the opportunity of an efficient wavelength tuning or, conversely, to stabilize the photoinduced effects in chalcogenide films as well as to improve their mechanical properties and/or their chemical durability, several pairs of materials from pure chalcogenide layers to chalcogenide/oxide layers were investigated. Different layer stacks were fabricated in order to check the compatibility between dissimilar materials which can have a strong influence on the interface roughness, adhesion, density, and homogeneity, for instance. Three different reflector designs were formulated and tested including all-chalcogenide layers (As{sub 40}Se{sub 60}/Ge{sub 25}Sb{sub 5}S{sub 70}) and mixed chalcogenide-oxide layers (As{sub 40}Se{sub 60}/alumino-silicate and Ga{sub 10}Ge{sub 15}Te{sub 75}/alumino-silicate). Prepared multilayers showed good compatibility between different material pairs deposited by laser ablation despite the diversity of chemical compositions. As{sub 40}Se{sub 60}/alumino-silicate reflector showed the best parameters; its stop band (R > 97% at 8° off-normal incidence) has a bandwidth of ∼ 100 nm and it is centered at 1490 nm. The quality of the different mirrors developed was good enough to try to obtain a microcavity structure for the 1.5 μm telecommunication wavelength made of chalcogenide layers. The microcavity structure consists of Ga{sub 5}Ge{sub 20}Sb{sub 10}S{sub 65} (doped with 5000 ppm of Er{sup 3+}) spacer surrounded by two 10-layer As{sub 40}Se{sub 60}/Ge{sub 25}Sb{sub 5}S{sub 70

Optical observations of Gamma-Ray Bursts

International Nuclear Information System (INIS)

Hjorth, J.; Pian, E.; Fynbo, J.P.U.

2004-01-01

We briefly review the status and recent progress in the field of optical observations of gamma-ray burst afterglows. We will focus on the fundamental observational evidence for the relationship between gamma-ray bursts and the final evolutionary phases of massive stars. In particular, we will address (i) gamma-ray burst host galaxies, (ii) optically dark gamma-ray burst afterglows, (iii) the gamma-ray burst-supernova connection, and (iv) the relation between X-ray flashes, gamma-ray bursts, and supernovae

The Physical Driver of the Optical Eigenvector 1 in Quasar Main Sequence

Energy Technology Data Exchange (ETDEWEB)

Panda, Swayamtrupta; Czerny, Bożena [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Warsaw (Poland); Wildy, Conor, E-mail: panda@cft.edu.pl [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland)

2017-11-07

Quasars are complex sources, characterized by broad band spectra from radio through optical to X-ray band, with numerous emission and absorption features. This complexity leads to rich diagnostics. However, Boroson and Green (1992) used Principal Component Analysis (PCA), and with this analysis they were able to show significant correlations between the measured parameters. The leading component, related to Eigenvector 1 (EV1) was dominated by the anticorrelation between the FeII optical emission and [OIII] line and EV1 alone contained 30% of the total variance. It opened a way in defining a quasar main sequence, in close analogy to the stellar main sequence on the Hertzsprung-Russel (HR) diagram (Sulentic et al., 2001). The question still remains which of the basic theoretically motivated parameters of an active nucleus (Eddington ratio, black hole mass, accretion rate, spin, and viewing angle) is the main driver behind the EV1. Here we limit ourselves to the optical waveband, and concentrate on theoretical modeling the FeII to Hβ ratio, and we test the hypothesis that the physical driver of EV1 is the maximum of the accretion disk temperature, reflected in the shape of the spectral energy distribution (SED). We performed computations of the Hβ and optical FeII for a broad range of SED peak position using CLOUDY photoionisation code. We assumed that both Hβ and FeII emission come from the Broad Line Region represented as a constant density cloud in a plane-parallel geometry. We expected that a hotter disk continuum will lead to more efficient production of FeII but our computations show that the FeII to Hβ ratio actually drops with the rise of the disk temperature. Thus either hypothesis is incorrect, or approximations used in our paper for the description of the line emissivity is inadequate.

The Physical Driver of the Optical Eigenvector 1 in Quasar Main Sequence

Directory of Open Access Journals (Sweden)

Swayamtrupta Panda

2017-11-01

Full Text Available Quasars are complex sources, characterized by broad band spectra from radio through optical to X-ray band, with numerous emission and absorption features. This complexity leads to rich diagnostics. However, Boroson and Green (1992 used Principal Component Analysis (PCA, and with this analysis they were able to show significant correlations between the measured parameters. The leading component, related to Eigenvector 1 (EV1 was dominated by the anticorrelation between the FeII optical emission and [OIII] line and EV1 alone contained 30% of the total variance. It opened a way in defining a quasar main sequence, in close analogy to the stellar main sequence on the Hertzsprung-Russel (HR diagram (Sulentic et al., 2001. The question still remains which of the basic theoretically motivated parameters of an active nucleus (Eddington ratio, black hole mass, accretion rate, spin, and viewing angle is the main driver behind the EV1. Here we limit ourselves to the optical waveband, and concentrate on theoretical modeling the FeII to Hβ ratio, and we test the hypothesis that the physical driver of EV1 is the maximum of the accretion disk temperature, reflected in the shape of the spectral energy distribution (SED. We performed computations of the Hβ and optical FeII for a broad range of SED peak position using CLOUDY photoionisation code. We assumed that both Hβ and FeII emission come from the Broad Line Region represented as a constant density cloud in a plane-parallel geometry. We expected that a hotter disk continuum will lead to more efficient production of FeII but our computations show that the FeII to Hβ ratio actually drops with the rise of the disk temperature. Thus either hypothesis is incorrect, or approximations used in our paper for the description of the line emissivity is inadequate.

Transparent Nanopore Cavity Arrays Enable Highly Parallelized Optical Studies of Single Membrane Proteins on Chip.

Science.gov (United States)

Diederichs, Tim; Nguyen, Quoc Hung; Urban, Michael; Tampé, Robert; Tornow, Marc

2018-06-13

Membrane proteins involved in transport processes are key targets for pharmaceutical research and industry. Despite continuous improvements and new developments in the field of electrical readouts for the analysis of transport kinetics, a well-suited methodology for high-throughput characterization of single transporters with nonionic substrates and slow turnover rates is still lacking. Here, we report on a novel architecture of silicon chips with embedded nanopore microcavities, based on a silicon-on-insulator technology for high-throughput optical readouts. Arrays containing more than 14 000 inverted-pyramidal cavities of 50 femtoliter volumes and 80 nm circular pore openings were constructed via high-resolution electron-beam lithography in combination with reactive ion etching and anisotropic wet etching. These cavities feature both, an optically transparent bottom and top cap. Atomic force microscopy analysis reveals an overall extremely smooth chip surface, particularly in the vicinity of the nanopores, which exhibits well-defined edges. Our unprecedented transparent chip design provides parallel and independent fluorescent readout of both cavities and buffer reservoir for unbiased single-transporter recordings. Spreading of large unilamellar vesicles with efficiencies up to 96% created nanopore-supported lipid bilayers, which are stable for more than 1 day. A high lipid mobility in the supported membrane was determined by fluorescent recovery after photobleaching. Flux kinetics of α-hemolysin were characterized at single-pore resolution with a rate constant of 0.96 ± 0.06 × 10 -3 s -1 . Here, we deliver an ideal chip platform for pharmaceutical research, which features high parallelism and throughput, synergistically combined with single-transporter resolution.

Improved Large Segmented Optics Fabrication Using Magnetorheological Finishing, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Primary mirrors for large aperture telescopes (> 10 m) are collections of smaller (1-2 m), typically hexagonal, often aspheric, optical segments. NASA's next...

Picosecond kinetics of the electron-hole layers formation in wide-bandgap II-VI type-II heterostructures

Energy Technology Data Exchange (ETDEWEB)

Filatov, E.V.; Zaitsev, S.V.; Tartakovskii, I.I.; Maksimov, A.A. [Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Moscow region (Russian Federation); Yakovlev, D.R. [A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Experimentelle Physik II, Technische Universitaet Dortmund (Germany); Waag, A. [Institute of Semiconductor Technology, Braunschweig Technical University, 38106 Braunschweig (Germany)

2010-06-15

Considerable slowdown of luminescence kinetics of the direct optical transition was discovered in ZnSe/BeTe type-II heterostructures under high levels of optical pumping. The effect is attributed to forming of a potential barrier for holes in the ZnSe layer due to band bending at high densities of spatially separated carriers. That results in a longer time of the photoexcited holes energy relaxation to their ground state in the BeTe layer. The decrease of overlapping of electron and hole wavefunctions in the ZnSe layer in thick ZnSe/BeTe structures at high levels of optical excitation reveals an additional important effect, that leads to sufficient retardation of radiative recombination time for photoexcited carriers (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

In-Space Distributed Fiber Optic Hydrogen Leak Sensor, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Broadband Photonics Inc. proposes development of a patent-pending distributed fiber optic sensor for in-space hydrogen leak detection. Reliable and fast detection of...

Silicon Carbide Lightweight Optics With Hybrid Skins for Large Cryo Telescopes, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Optical Physics Company (OPC) has developed new silicon carbide (SiC) foam-based optics with hybrid skins that are composite, athermal and lightweight (FOCAL) that...

Overview of Optical and Thermal Laser-Tissue Interaction and Nomenclature

Science.gov (United States)

Welch, Ashley J.; van Gemert, Martin J. C.

The development of a unified theory for the optical and thermal response of tissue to laser radiation is no longer in its infancy, though it is still not fully developed. This book describes our current understanding of the physical events that can occur when light interacts with tissue, particularly the sequence of formulations that estimate the optical and thermal responses of tissue to laser radiation. This overview is followed by an important chapter that describes the basic interactions of light with tissue. Part I considers basic tissue optics. Tissue is treated as an absorbing and scattering medium and methods are presented for calculating and measuring light propagation, including polarized light. Also, methods for estimating tissue optical properties from measurements of reflection and transmission are discussed. Part II concerns the thermal response of tissue owing to absorbed light, and rate reactions are presented for predicting the extent of laser induced thermal damage. Methods for measuring temperature, thermal properties, rate constants, pulsed ablation and laser tissue interactions are detailed. Part III is devoted to examples that use the theory presented in Parts I and II to analyze various medical applications of lasers. Discussions of Optical Coherence Tomography (OCT), forensic optics, and light stimulation of nerves are also included.

Three-Dimensional Optical Coherence Tomography (3D OCT), Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Applied Science Innovations, Inc. proposes a new tool of 3D optical coherence tomography (OCT) for cellular level imaging at video frame rates and dramatically...

Los Alamos progress report for RIPL-II

International Nuclear Information System (INIS)

Young, P.G.; Chadwick, M.B.; Moeller, P.

2000-01-01

Since the last RIPL-II CRP meeting, we have developed a code that prepares inputs from the RIPL-I optical model parameter data base for the SCAT2 and ECIS96 computer codes. We have also made limited corrections to the optical model parameter file, and have made minor extensions to the format for optical potentials. We have implemented mass information from the RIPL-I mass library into the ground-state mass/spin/parity file (Tape13) used in GNASH and other codes. Additionally, we have developed software for using the generalized superfluid level density model on SUN computers at LANL, ultimately for use of the RIPL-I level density information in the GNASH code. (author)

Modeling Type II-P/II-L Supernovae Interacting with Recent Episodic Mass Ejections from Their Presupernova Stars with MESA and SNEC

Science.gov (United States)

Das, Sanskriti; Ray, Alak

2017-12-01

We show how dense, compact, discrete shells of circumstellar gas immediately outside of red supergiants affect the optical light curves of Type II-P/II-L supernovae (SNe), using the example of SN 2013ej. Earlier efforts in the literature had used an artificial circumstellar medium (CSM) stitched to the surface of an evolved star that had not gone through a phase of late-stage heavy mass loss, which, in essence, is the original source of the CSM. In contrast, we allow enhanced mass-loss rate from the modeled star during the 16O and 28Si burning stages and construct the CSM from the resulting mass-loss history in a self-consistent way. Once such evolved pre-SN stars are exploded, we find that the models with early interaction between the shock and the dense CSM reproduce light curves far better than those without that mass loss and, hence, having no nearby dense CSM. The required explosion energy for the progenitors with a dense CSM is reduced by almost a factor of two compared to those without the CSM. Our model, with a more realistic CSM profile and presupernova and explosion parameters, fits observed data much better throughout the rise, plateau, and radioactive tail phases as compared to previous studies. This points to an intermediate class of supernovae between Type II-P/II-L and Type II-n SNe with the characteristics of simultaneous UV and optical peak, slow decline after peak, and a longer plateau.

Distribution of Si II in the Galactic center

Science.gov (United States)

Graf, P.; Herter, T.; Gull, G. E.; Houck, J. R.

1988-01-01

A map of the Galactic center region in the forbidden Si II 34.8-micron line is presented. The line emission arises from within the photodissociation region (PDR) associated with the neutral gas ring surrounding an ionized gas core confined within 2 pc of the Galactic center. Si II is a useful probe of the inner regions of the ring since it is always optically thin. The Si II data, when analyzed in conjunction with O I, C II, and molecular measurements, outlines the transition region between the PDR and the surrounding molecular cloud. The Si II emission is found to extend beyond that of the O II into the neutral gas ring. Although the interpretation is not unique, the data are consistent with a constant gas-phase abundance of silicon within the inner part of the PDR while the gaseous silicon is depleted by molecule formation in the transition region.

Parallel computing in experimental mechanics and optical measurement: A review (II)

Science.gov (United States)

Wang, Tianyi; Kemao, Qian

2018-05-01

With advantages such as non-destructiveness, high sensitivity and high accuracy, optical techniques have successfully integrated into various important physical quantities in experimental mechanics (EM) and optical measurement (OM). However, in pursuit of higher image resolutions for higher accuracy, the computation burden of optical techniques has become much heavier. Therefore, in recent years, heterogeneous platforms composing of hardware such as CPUs and GPUs, have been widely employed to accelerate these techniques due to their cost-effectiveness, short development cycle, easy portability, and high scalability. In this paper, we analyze various works by first illustrating their different architectures, followed by introducing their various parallel patterns for high speed computation. Next, we review the effects of CPU and GPU parallel computing specifically in EM & OM applications in a broad scope, which include digital image/volume correlation, fringe pattern analysis, tomography, hyperspectral imaging, computer-generated holograms, and integral imaging. In our survey, we have found that high parallelism can always be exploited in such applications for the development of high-performance systems.

Optical pulse coupling in a photorefractive crystal, propagation of encoded pulses in an optical fiber, and phase conjugate optical interconnections

Energy Technology Data Exchange (ETDEWEB)

Yao, X.S.

1992-01-01

In Part I, the author presents a theory to describe the interaction between short optical pulses in a photorefractive crystal. This theory provides an analytical framework for pulse coherence length measurements using a photorefractive crystal. The theory also predicts how a pulse changes its temporal shape due to its coupling with another pulse in a photorefractive crystal. The author describes experiments to demonstrate how photorefractive coupling alters the temporal shape and the frequency spectrum of an optical pulse. The author describes a compact optical field correlator. Using this correlator, the author measured the field cross-correlation function of optical pulses using a photorefractive crystal. The author presents a more sophisticated theory to describe the photorefractive coupling of optical pulses that are too short for the previous theory to be valid. In Part II of this dissertation, the author analyzes how the group-velocity dispersion and the optical nonlinearity of an optical fiber ruin an fiberoptic code-division multiple-access (CDMA) communication system. The author treats the optical fiber's nonlinear response with a novel approach and derives the pulse propagation equation. Through analysis and numerically simulations, the author obtains the maximum and the maximum allowed peak pulse power, as well as the minimum and the maximum allowed pulse width for the communication system to function properly. The author simulates how the relative misalignment between the encoding and the decoding masks affects the system's performance. In Part III the author demonstrates a novel optical interconnection device based on a mutually pumped phase conjugator. This device automatically routes light from selected information-sending channels to selected information-receiving channels, and vice versa. The phase conjugator eliminates the need for critical alignment. It is shown that a large number of optical channels can be interconnected using this

Integrated optics and optoelectronics II; Proceedings of the Meeting, San Jose, CA, Sept. 17-19, 1990

International Nuclear Information System (INIS)

Wong, Ka-Kha

1991-01-01

The present volume on integrated optics and optoelectronics discusses proton- and ion-exchange technologies, radiation effects on GaAs optical system FET devices and on the dynamical behavior of LiNbO3 switching devices, advanced lightwave components and concepts, advanced optical interconnects concepts, advanced aircraft and engine control, IOCs for fiber-optic gyroscopes, and commercial integrated optical devices. Attention is given to integrated optical devices for high-data-rate serial-to-parallel conversion, the design of novel integrated optic devices using depressed index waveguides, and a low-loss L-band microwave fiber-optic link for control of a T/R module. Topics addressed include the temperature and modulation dependence of spectral linewidth in distributed Bragg reflector laser diodes, length-minimization design considerations in photonic integrated circuits incorporating directional couplers, and the photochemical formation of polymeric optical waveguides and devices for optical interconnection applications

Cavity optomechanics in gallium phosphide microdisks

International Nuclear Information System (INIS)

Mitchell, Matthew; Barclay, Paul E.; Hryciw, Aaron C.

2014-01-01

We demonstrate gallium phosphide (GaP) microdisk optical cavities with intrinsic quality factors >2.8 × 10 5 and mode volumes 3 , and study their nonlinear and optomechanical properties. For optical intensities up to 8.0 × 10 4 intracavity photons, we observe optical loss in the microcavity to decrease with increasing intensity, indicating that saturable absorption sites are present in the GaP material, and that two-photon absorption is not significant. We observe optomechanical coupling between optical modes of the microdisk around 1.5 μm and several mechanical resonances, and measure an optical spring effect consistent with a theoretically predicted optomechanical coupling rate g 0 /2π∼30 kHz for the fundamental mechanical radial breathing mode at 488 MHz

Identifying the role of the local density of optical states in frequency conversion of light in confined media

NARCIS (Netherlands)

Yuce, E.; Ctistis, Georgios; Claudon, J.; Gerard, J.M.; Vos, Willem L.

2014-01-01

We have reversibly switched the resonance of a GaAs-AlAs microcavity in the near-infrared near λ=1300 nm within 300 fs by the electronic Kerr effect. We reveal by pump-probe spectroscopy a remarkable red shift or blue shift of the light confined inside the cavity for small pulse delays, depending on

Simulating the Mg II NUV Spectra & C II Resonance Lines During Solar Flares

Science.gov (United States)

Kerr, Graham Stewart; Allred, Joel C.; Leenaarts, Jorrit; Butler, Elizabeth; Kowalski, Adam

2017-08-01

The solar chromosphere is the origin of the bulk of the enhanced radiative output during solar flares, and so comprehensive understanding of this region is important if we wish to understand energy transport in solar flares. It is only relatively recently, however, with the launch of IRIS that we have routine spectroscopic flarea observations of the chromsphere and transition region. Since several of the spectral lines observed by IRIS are optically thick, it is necessary to use forward modelling to extract the useful information that these lines carry about the flaring chromosphere and transition region. We present the results of modelling the formation properties Mg II resonance lines & subordinate lines, and the C II resonance lines during solar flares. We focus on understanding their relation to the physical strucutre of the flaring atmosphere, exploiting formation height differences to determine if we can extract information about gradients in the atmosphere. We show the effect of degrading the profiles to the resolution of the IRIS, and that the usual observational techniques used to identify the line centroid do a poor job in the early stages of the flare (partly due to multiple optically thick line components). Finally, we will tentatively comment on the effects that 3D radiation transfer may have on these lines.

Silicon-Nitride-based Integrated Optofluidic Biochemical Sensors using a Coupled-Resonator Optical Waveguide

Directory of Open Access Journals (Sweden)

Jiawei eWANG

2015-04-01

Full Text Available Silicon nitride (SiN is a promising material platform for integrating photonic components and microfluidic channels on a chip for label-free, optical biochemical sensing applications in the visible to near-infrared wavelengths. The chip-scale SiN-based optofluidic sensors can be compact due to a relatively high refractive index contrast between SiN and the fluidic medium, and low-cost due to the complementary metal-oxide-semiconductor (CMOS-compatible fabrication process. Here, we demonstrate SiN-based integrated optofluidic biochemical sensors using a coupled-resonator optical waveguide (CROW in the visible wavelengths. The working principle is based on imaging in the far field the out-of-plane elastic-light-scattering patterns of the CROW sensor at a fixed probe wavelength. We correlate the imaged pattern with reference patterns at the CROW eigenstates. Our sensing algorithm maps the correlation coefficients of the imaged pattern with a library of calibrated correlation coefficients to extract a minute change in the cladding refractive index. Given a calibrated CROW, our sensing mechanism in the spatial domain only requires a fixed-wavelength laser in the visible wavelengths as a light source, with the probe wavelength located within the CROW transmission band, and a silicon digital charge-coupled device (CCD / CMOS camera for recording the light scattering patterns. This is in sharp contrast with the conventional optical microcavity-based sensing methods that impose a strict requirement of spectral alignment with a high-quality cavity resonance using a wavelength-tunable laser. Our experimental results using a SiN CROW sensor with eight coupled microrings in the 680nm wavelength reveal a cladding refractive index change of ~1.3 × 10^-4 refractive index unit (RIU, with an average sensitivity of ~281 ± 271 RIU-1 and a noise-equivalent detection limit (NEDL of 1.8 ×10^-8 RIU ~ 1.0 ×10^-4 RIU across the CROW bandwidth of ~1 nm.

Synthesis of bis(oxamato) transition metal complexes and Ni nanoparticles and their structural, magnetic, optical, and magneto-optical characterization

Energy Technology Data Exchange (ETDEWEB)

Braeuer, Bjoern

2008-07-02

In the framework of this thesis mono- and oligonuclear Cu(II)- anf Ni(II)-bis(oxamato) complexes are synthesized in view on their magneto-optical properties and structurally characterized. About transition-charge and transition-metal induced deviations from the general reaction behaviour described in literature is reported. From electron-spin-resonance studies the spin-density distribution in the mononuclear Cu(II) complexes is derived. The influence on this by coordination geometry as well as the effects of the superexchange interaction are discussed and compared with results from the density functional theory (DFT). Trinuclear bis(oxamato) complexes are for the first time deposited on Si(111) substrates by spin coating and studied by means of the spectroscopic ellipsometry as well as the Raman spectroscopy and evaluated by means of DFT calculations. Magneto-optical Kerr-effect studies were performed on thin layers of these complexes as well as phthalocyanines. For the comparison the magnetic and magneto-optical properties of Ni nanoparticles in different organic matrices were studied. By means of the photoelectron spectroscopy the oxidation behaviour of these is studied and conclusions on charge-transfer processes between the matrices and the nanoparticles are drawn. [German] Im Rahmen dieser Arbeit werden ein- und mehrkernige Cu(II)- und Ni(II)-bis-(oxamato)-Komplexe im Hinblick auf ihre magneto-optischen Eigenschaften gezielt hergestellt und strukturell charakterisiert. Ueber ladungs- und uebergangsmetallinduzierte Abweichungen vom allgemeinen in der Literatur beschriebenen Reaktionsverhalten wird berichtet. Aus Elektronenspinresonanz-Untersuchungen wird die Spindichteverteilung in den einkernigen Cu(II)-Komplexen abgeleitet. Die Beeinflussung dieser durch die Koordinationsgeometrie sowie die Auswirkungen auf die Superaustausch- Wechselwirkung werden diskutiert und mit Ergebnissen der Dichtefunktionaltheorie (DFT) verglichen. Dreikernige bis

Experience with parallel optical link for the CDF silicon detector

International Nuclear Information System (INIS)

Hou, S.

2003-01-01

The Dense Optical Interface Module (DOIM) is a byte-wide optical link developed for the Run II upgrade of the CDF silicon tracking system [1]. The module consists of a transmitter with a laser-diode array for conversion of digitized detector signals to light outputs, a 22 m optical fiber ribbon cable for light transmission, and a receiver converting the light pulses back to electrical signals. We report on the design feature, characteristics, and radiation tolerance

Calibration and Limitations of the Mg II Line-based Black Hole Masses

Science.gov (United States)

Woo, Jong-Hak; Le, Huynh Anh N.; Karouzos, Marios; Park, Dawoo; Park, Daeseong; Malkan, Matthew A.; Treu, Tommaso; Bennert, Vardha N.

2018-06-01

We present single-epoch black hole mass ({M}BH}) calibrations based on the rest-frame ultraviolet (UV) and optical measurements of Mg II 2798 Å and Hβ 4861 Å lines and the active galactic nucleus (AGN) continuum, using a sample of 52 moderate-luminosity AGNs at z ∼ 0.4 and z ∼ 0.6 with high-quality Keck spectra. We combine this sample with a large number of luminous AGNs from the Sloan Digital Sky Survey to increase the dynamic range for a better comparison of UV and optical velocity and luminosity measurements. With respect to the reference {M}BH} based on the line dispersion of Hβ and continuum luminosity at 5100 Å, we calibrate the UV and optical mass estimators by determining the best-fit values of the coefficients in the mass equation. By investigating whether the UV estimators show a systematic trend with Eddington ratio, FWHM of Hβ, Fe II strength, or UV/optical slope, we find no significant bias except for the slope. By fitting the systematic difference of Mg II-based and Hβ-based masses with the L 3000/L 5100 ratio, we provide a correction term as a function of the spectral index as ΔC = 0.24 (1 + α λ ) + 0.17, which can be added to the Mg II-based mass estimators if the spectral slope can be well determined. The derived UV mass estimators typically show >∼0.2 dex intrinsic scatter with respect to the Hβ-based {M}BH}, suggesting that the UV-based mass has an additional uncertainty of ∼0.2 dex, even if high-quality rest-frame UV spectra are available.

Investigation of the physics of diamond MEMS : diamond allotrope lithography

International Nuclear Information System (INIS)

Zalizniak, I.; Olivero, P.; Jamieson, D.N.; Prawer, S.; Reichart, P.; Rubanov, S.; Petriconi, S.

2005-01-01

We propose a novel lithography process in which ion induced phase transfomations of diamond form sacrificial layers allowing the fabrication of small structures including micro-electromechanical systems (MEMS). We have applied this novel lithography to the fabrication of diamond microcavities, cantilevers and optical waveguides. In this paper we present preliminary experiments directed at the fabrication of suspended diamond disks that have the potential for operation as optical resonators. Such structures would be very durable and resistant to chemical attack with potential applications as novel sensors for extreme environments or high temperature radiation detectors. (author). 3 refs., 3 figs

Lithographically-Scribed Planar Holographic Optical CDMA Devices and Systems

National Research Council Canada - National Science Library

Mossberg, Thomas

2007-01-01

.... The present Phase II effort has harnessed new fabrication tools to perfect disruptive HBR-based multiplexer products for DoD avionics, optical communications systems computer data communications and local area networks...

Synthesis and structural characterisation of iron(II) and copper(II) diphosphates containing flattened metal oxotetrahedra

Energy Technology Data Exchange (ETDEWEB)

Keates, Adam C. [School of Chemistry, University of Southampton, Southampton, Hampshire SO17 1B,. UK (United Kingdom); Wang, Qianlong [Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (United Kingdom); Weller, Mark T., E-mail: m.t.weller@bath.ac.uk [Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (United Kingdom)

2014-02-15

Single crystal and bulk polycrystalline forms of K{sub 2}MP{sub 2}O{sub 7} (M=Fe(II), Cu(II)) have been synthesised and their structures determined from single crystal X-ray diffraction data. Both compounds crystallize in the tetragonal system, space group P-42{sub 1}m. Their structures are formed from infinite sheets of linked oxopolyhedra of the stoichiometry [MP{sub 2}O{sub 7}]{sup 2−} with potassium cations situated between the layers. The MO{sub 4} tetrahedra share oxygen atoms with [P{sub 2}O{sub 7}]{sup 4−} diphosphate groups and the potassium ions have KO{sub 8} square prismatic geometry. In both compounds the M(II) centre has an unusual strongly flattened, tetrahedral coordination to oxygen, as a result of the Jahn–Teller (JT) effect for the high spin d{sup 6} Fe(II) and p-orbital mixing or a second order JT effect for d{sup 9} Cu(II) centres in four fold coordination. The uncommon transition metal ion environments found in these materials are reflected in their optical absorption spectra and magnetism data. - Graphical abstract: The structures of the tetragonal polymorphs of K{sub 2}MP{sub 2}O{sub 7}, M=Cu(II), Fe(II), consist of infinite sheets of stoichiometry [MP{sub 2}O{sub 7}]{sup 2−}, formed from linked pyrophosphate groups and MO{sub 4} tetrahedra, separated by potassium ions. In both compounds the unusual tetrahedral coordination of the M(II) centre is strongly flattened as a result of Jahn–Teller (JT) effects for high spin, d{sup 6} Fe(II) and p-orbital mixing and second-order JT effects for d{sup 9} Cu(II). Display Omitted - Highlights: • Tetrahedral copper and iron(II) coordinated by oxygen. • New layered phosphate structure. • Jahn–Teller and d{sup 10} distorted coordinations.

Synthesis and structural characterisation of iron(II) and copper(II) diphosphates containing flattened metal oxotetrahedra

International Nuclear Information System (INIS)

Keates, Adam C.; Wang, Qianlong; Weller, Mark T.

2014-01-01

Single crystal and bulk polycrystalline forms of K 2 MP 2 O 7 (M=Fe(II), Cu(II)) have been synthesised and their structures determined from single crystal X-ray diffraction data. Both compounds crystallize in the tetragonal system, space group P-42 1 m. Their structures are formed from infinite sheets of linked oxopolyhedra of the stoichiometry [MP 2 O 7 ] 2− with potassium cations situated between the layers. The MO 4 tetrahedra share oxygen atoms with [P 2 O 7 ] 4− diphosphate groups and the potassium ions have KO 8 square prismatic geometry. In both compounds the M(II) centre has an unusual strongly flattened, tetrahedral coordination to oxygen, as a result of the Jahn–Teller (JT) effect for the high spin d 6 Fe(II) and p-orbital mixing or a second order JT effect for d 9 Cu(II) centres in four fold coordination. The uncommon transition metal ion environments found in these materials are reflected in their optical absorption spectra and magnetism data. - Graphical abstract: The structures of the tetragonal polymorphs of K 2 MP 2 O 7 , M=Cu(II), Fe(II), consist of infinite sheets of stoichiometry [MP 2 O 7 ] 2− , formed from linked pyrophosphate groups and MO 4 tetrahedra, separated by potassium ions. In both compounds the unusual tetrahedral coordination of the M(II) centre is strongly flattened as a result of Jahn–Teller (JT) effects for high spin, d 6 Fe(II) and p-orbital mixing and second-order JT effects for d 9 Cu(II). Display Omitted - Highlights: • Tetrahedral copper and iron(II) coordinated by oxygen. • New layered phosphate structure. • Jahn–Teller and d 10 distorted coordinations

Linear and Nonlinear Impairment Compensation in Coherent Optical Transmission with Digital Signal Processing

DEFF Research Database (Denmark)

Porto da Silva, Edson

Digital signal processing (DSP) has become one of the main enabling technologies for the physical layer of coherent optical communication networks. The DSP subsystems are used to implement several functionalities in the digital domain, from synchronization to channel equalization. Flexibility...... nonlinearity compensation, (II) spectral shaping, and (III) adaptive equalization. For (I), original contributions are presented to the study of the nonlinearity compensation (NLC) with digital backpropagation (DBP). Numerical and experimental performance investigations are shown for different application...... scenarios. Concerning (II), it is demonstrated how optical and electrical (digital) pulse shaping can be allied to improve the spectral confinement of a particular class of optical time-division multiplexing (OTDM) signals that can be used as a building block for fast signaling single-carrier transceivers...

Optical spectra and radio properties of quasars

International Nuclear Information System (INIS)

Wills, B.J.

1982-01-01

Using high quality spectrophotometric scans obtained at the McDonald Observatory, and data from the literature the author shows that, for quasars, the relative strength of optical Fe II emission (the broad blended feature lambda4570) may be roughly inversely proportional to line widths (full width at half maximum, FWHM). A similar relation between the relative intensity of the UV Fe II blend between 2300 and 2600 A (the lambda2500 feature) and the widths of Mg II and Hβ is shown. She distinguishes between compact and extended radio sources and includes radio quiet quasars, Seyfert 1 galaxies and BLRG's. The quasars associated with extended radio sources have the broadest emission lines and the weakest Fe II, falling close to the region occupied by BLRG's which also have extended radio structure. Those quasars with strong Fe II and compact radio structure are most similar to the Seyfert 1 galaxies. (Auth.)

The At-Wavelength Metrology Facility at BESSY-II

Directory of Open Access Journals (Sweden)

Franz Schäfers

2016-02-01

Full Text Available The At-Wavelength Metrology Facility at BESSY-II is dedicated to short-term characterization of novel UV, EUV and XUV optical elements, such as diffraction gratings, mirrors, multilayers and nano-optical devices like reflection zone plates. It consists of an Optics Beamline PM-1 and a Reflectometer in a clean-room hutch as a fixed end station. The bending magnet Beamline is a Plane Grating Monochromator beamline (c-PGM equipped with an SX700 monochromator. The beamline is specially tailored for efficient high-order suppression and stray light reduction. The versatile 11-axes UHV-Reflectometer can house life-sized optical elements, which are fully adjustable and of which the reflection properties can be measured in the full incidence angular range as well as in the full azimuthal angular range to determine polarization properties.

Optical and infrared observations of SN 1987A from Cerro Tololo Inter-American Observatory

International Nuclear Information System (INIS)

Phillips, M.M.

1988-01-01

Results from optical and infrared observations of SN 1987A obtained at Cerro Tololo Inter-American Observatory over the first seven months since core collapse are reviewed. Around 130 days after outburst, the bolometric light curve began to smoothly decline at a rate of ∼ 0.01 mag day-1, providing dramatic confirmation of the prediction that radioactivity had powered the optical display after the first month./ the peculiar color changes are kinks observed beginning on the 25th day probably signaled the initial release of trapped energy from mass 56 material. The bolometric luminosity of SN 1987A was unusually low at first, but reached a value more typical of other type II supernovae by the time that the final exponential decline had begun. Over much of the period covered by these observations, the optical and infrared spectra were characterized by strong absorption lines of Ba II and Sr II. Comparison with the spectra of other type II supernovae at similar stages of evolution supports the suggestion that s-processed elements were enriched in the hydrogen envelope of the progenitor, Sanduleak - 69 degrees 202

Bulk crystal growth and nonlinear optical characterization of semiorganic single crystal: Cadmium (II) dibromide L - Proline monohydrate

Energy Technology Data Exchange (ETDEWEB)

Balakrishnan, T., E-mail: balacrystalgrowth@gmail.com [Crystal Growth Laboratory, PG & Research Department of Physics, Periyar EVR College (Autonomous), Tiruchirappalli, 620 023, Tamil Nadu (India); Sathiskumar, S. [Crystal Growth Laboratory, PG & Research Department of Physics, Periyar EVR College (Autonomous), Tiruchirappalli, 620 023, Tamil Nadu (India); Ramamurthi, K. [Crystal Growth and Thin Film Laboratory, Department of Physics and Nanotechnology, SRM University, Kattankulathur, 603 203, Kancheepuram, Tamil Nadu (India); Thamotharan, S. [Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA University, Thanjavur, 613 401 (India)

2017-01-15

Single crystal of a novel metal organic nonlinear optical (NLO) cadmium (II) dibromide L - proline monohydrate (CBLPM) of size 7 × 7 × 5 mm{sup 3} was grown from slow evaporation technique. Single crystal X – ray diffraction analysis reveals that the crystal belongs to orthorhombic system with lattice parameters a = 10.1891 (8) Å, b = 13.4961 (11) Å, c = 7.4491 (5) Å and space group P2{sub 1}2{sub 1}2{sub 1}. The powder X – ray diffraction pattern of CBLPM was recorded and the X – ray diffraction peaks were indexed. The various functional groups of CBLPM were identified by the FT – IR and FT – Raman spectral analyses. The optical transmittance window and lower cut off wavelength of CBLPM were identified from UV – Vis – NIR studies. The mechanical strength of the grown crystal was estimated using Vickers microhardness test. Dielectric constant and dielectric loss measurements were carried out at different temperatures in the frequency range of 50 Hz - 2 MHz. The photoluminescence spectrum was recorded in the wavelength range 200–400 nm and the estimated optical band gap was ∼4.1 eV. Etching studies were carried out for different etching time. Thermal stability of CBLPM was determined using thermogravimetric analysis. Laser induced damage threshold study was carried out for the grown crystal using Nd:YAG laser. Size dependent second harmonic generation efficiency of the grown crystal was determined by Kurtz and Perry powder technique with different particle size using Nd:YAG laser with wavelength 1064 nm. Second harmonic generation efficiency of the powdered CBLPM crystal was ∼2.3 times that of potassium dihydrogen orthophosphate. - Highlights: • CBLPM crystal belongs to orthorhombic crystal system with space group P2{sub 1}2{sub 1}2{sub 1.} • Transmittance of CBLPM is ∼80% in the 650–1100 nm range. • Powder SHG efficiency of CBLPM increases with increase in particle size. • SHG efficiency of 0.57 μm size powdered CBLPM is ∼2

Ocean Optics Protocols for Satellite Ocean Color Sensor Validation, Revision 4, Volume IV: Inherent Optical Properties: Instruments, Characterizations, Field Measurements and Data Analysis Protocols

Science.gov (United States)

Mueller, J. L.; Fargion, G. S.; McClain, C. R. (Editor); Pegau, S.; Zanefeld, J. R. V.; Mitchell, B. G.; Kahru, M.; Wieland, J.; Stramska, M.

2003-01-01

This document stipulates protocols for measuring bio-optical and radiometric data for the Sensor Intercomparision and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project activities and algorithm development. The document is organized into 6 separate volumes as Ocean Optics Protocols for Satellite Ocean Color Sensor Validation, Revision 4. Volume I: Introduction, Background, and Conventions; Volume II: Instrument Specifications, Characterization and Calibration; Volume III: Radiometric Measurements and Data Analysis Methods; Volume IV: Inherent Optical Properties: Instruments, Characterization, Field Measurements and Data Analysis Protocols; Volume V: Biogeochemical and Bio-Optical Measurements and Data Analysis Methods; Volume VI: Special Topics in Ocean Optics Protocols and Appendices. The earlier version of Ocean Optics Protocols for Satellite Ocean Color Sensor Validation, Revision 3 is entirely superseded by the six volumes of Revision 4 listed above.

Early tumor detection afforded by in vivo imaging of near-infrared II fluorescence.

Science.gov (United States)

Tao, Zhimin; Dang, Xiangnan; Huang, Xing; Muzumdar, Mandar D; Xu, Eric S; Bardhan, Neelkanth Manoj; Song, Haiqin; Qi, Ruogu; Yu, Yingjie; Li, Ting; Wei, Wei; Wyckoff, Jeffrey; Birrer, Michael J; Belcher, Angela M; Ghoroghchian, P Peter

2017-07-01

Cell-intrinsic reporters such as luciferase (LUC) and red fluorescent protein (RFP) have been commonly utilized in preclinical studies to image tumor growth and to monitor therapeutic responses. While extrinsic reporters that emit near infrared I (NIR-I: 650-950 nm) or near-infrared II (NIR-II: 1000-1700 nm) optical signals have enabled minimization of tissue autofluorescence and light scattering, it has remained unclear as to whether their use has afforded more accurate tumor imaging in small animals. Here, we developed a novel optical imaging construct comprised of rare earth lanthanide nanoparticles coated with biodegradable diblock copolymers and doped with organic fluorophores, generating NIR-I and NIR-II emissive bands upon optical excitation. Simultaneous injection of multiple spectrally-unique nanoparticles into mice bearing tumor implants established via intraperitoneal dissemination of LUC + /RFP + OVCAR-8 ovarian cancer cells enabled direct comparisons of imaging with extrinsic vs. intrinsic reporters, NIR-II vs. NIR-I signals, as well as targeted vs. untargeted exogenous contrast agents in the same animal and over time. We discovered that in vivo optical imaging at NIR-II wavelengths facilitates more accurate detection of smaller and earlier tumor deposits, offering enhanced sensitivity, improved spatial contrast, and increased depths of tissue penetration as compared to imaging with visible or NIR-I fluorescent agents. Our work further highlights the hitherto underappreciated enhancements in tumor accumulation that may be achieved with intraperitoneal as opposed to intravenous administration of nanoparticles. Lastly, we found discrepancies in the fidelity of tumor uptake that could be obtained by utilizing small molecules for in vivo as opposed to in vitro targeting of nanoparticles to disseminated tumors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bridging ultrahigh-Q devices and photonic circuits

Science.gov (United States)

Yang, Ki Youl; Oh, Dong Yoon; Lee, Seung Hoon; Yang, Qi-Fan; Yi, Xu; Shen, Boqiang; Wang, Heming; Vahala, Kerry

2018-05-01

Optical microresonators are essential to a broad range of technologies and scientific disciplines. However, many of their applications rely on discrete devices to attain challenging combinations of ultra-low-loss performance (ultrahigh Q) and resonator design requirements. This prevents access to scalable fabrication methods for photonic integration and lithographic feature control. Indeed, finding a microfabrication bridge that connects ultrahigh-Q device functions with photonic circuits is a priority of the microcavity field. Here, an integrated resonator having a record Q factor over 200 million is presented. Its ultra-low-loss and flexible cavity design brings performance to integrated systems that has been the exclusive domain of discrete silica and crystalline microcavity devices. Two distinctly different devices are demonstrated: soliton sources with electronic repetition rates and high-coherence/low-threshold Brillouin lasers. This multi-device capability and performance from a single integrated cavity platform represents a critical advance for future photonic circuits and systems.

Evaluation of Laser Stabilization and Imaging Systems for LCLS-II - Final Paper

Energy Technology Data Exchange (ETDEWEB)

Barry, Matthew [Auburn Univ., AL (United States)

2015-08-20

By combining the top performing commercial laser beam stabilization system with the most ideal optical imaging configuration, the beamline for the Linear Accelerator Coherent Light Source II (LCLS-II) will deliver the highest quality and most stable beam to the cathode. To determine the optimal combination, LCLS-II beamline conditions were replicated and the systems tested with a He-Ne laser. The Guidestar-II and MRC active laser beam stabilization systems were evaluated for their ideal positioning and stability. Both a two and four lens optical imaging configuration was then evaluated for beam imaging quality, magnification properties, and natural stability. In their best performances when tested over fifteen hours, Guidestar-II kept the beam stable over approximately 70-110um while the MRC system kept it stable over approximately 90-100um. During short periods of time, Guidestar-II kept the beam stable between 10-20um, but was more susceptible to drift over time, while the MRC system maintained the beam between 30-50um with less overall drift. The best optical imaging configuration proved to be a four lens system that images to the iris located in the cathode room and from there, imaged to the cathode. The magnification from the iris to the cathode was 2:1, within an acceptable tolerance to the expected 2.1:1 magnification. The two lens configuration was slightly more stable in small periods of time (less than 10 minutes) without the assistance of a stability system, approximately 55um compared to approximately 70um, but the four lens configurations beam image had a significantly flatter intensity distribution compared to the two lens configuration which had a Gaussian distribution. A final test still needs to be run with both stability systems running at the same time through the four lens system. With this data, the optimal laser beam stabilization system can be determined for the beamline of LCLS-II.

On-chip dual comb source for spectroscopy

OpenAIRE

Dutt, Avik; Joshi, Chaitanya; Ji, Xingchen; Cardenas, Jaime; Okawachi, Yoshitomo; Luke, Kevin; Gaeta, Alexander L.; Lipson, Michal

2016-01-01

Dual-comb spectroscopy is a powerful technique for real-time, broadband optical sampling of molecular spectra which requires no moving components. Recent developments with microresonator-based platforms have enabled frequency combs at the chip scale. However, the need to precisely match the resonance wavelengths of distinct high-quality-factor microcavities has hindered the development of an on-chip dual comb source. Here, we report the first simultaneous generation of two microresonator comb...

Bose-Einstein condensation of paraxial light

OpenAIRE

Klaers, J.; Schmitt, J.; Damm, T.; Vewinger, F.; Weitz, M.

2011-01-01

Photons, due to the virtually vanishing photon-photon interaction, constitute to very good approximation an ideal Bose gas, but owing to the vanishing chemical potential a (free) photon gas does not show Bose-Einstein condensation. However, this is not necessarily true for a lower-dimensional photon gas. By means of a fluorescence induced thermalization process in an optical microcavity one can achieve a thermal photon gas with freely adjustable chemical potential. Experimentally, we have obs...

Transition operators in electromagnetic-wave diffraction theory. II - Applications to optics

Science.gov (United States)

Hahne, G. E.

1993-01-01

The theory developed by Hahne (1992) for the diffraction of time-harmonic electromagnetic waves from fixed obstacles is briefly summarized and extended. Applications of the theory are considered which comprise, first, a spherical harmonic expansion of the so-called radiation impedance operator in the theory, for a spherical surface, and second, a reconsideration of familiar short-wavelength approximation from the new standpoint, including a derivation of the so-called physical optics method on the basis of quasi-planar approximation to the radiation impedance operator, augmented by the method of stationary phase. The latter includes a rederivation of the geometrical optics approximation for the complete Green's function for the electromagnetic field in the presence of a smooth- and a convex-surfaced perfectly electrically conductive obstacle.

Waveguide-based optofluidics

DEFF Research Database (Denmark)

Karnutsch, Christian; Tomljenovic-Hanic, Snjezana; Monat, Christelle

2010-01-01

blocks in many applications, from microlasers and biomedical sensor systems to optical switches and integrated circuits. In this paper, we show that PhC microcavities can be formed by infusing a liquid into a selected section of a uniform PhC waveguide and that the optical properties of these cavities...... and highlight the benefits of an optofluidic approach, focusing on optofluidic cavities created in silicon photonic crystal (PhC) waveguide platforms. These cavities can be spatially and spectrally reconfigured, thus allowing a dynamic control of their optical characteristics. PhC cavities are major building...... can be tuned and adapted. By taking advantage of the negative thermo-optic coefficient of liquids, we describe a method which renders PhC cavities insensitive to temperature changes in the environment. This is only one example where the fluid-control of optical elements results in a functionality...

Fiber Coupled Pulse Shaper for Sub-Nanosecond Pulse Lidar, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This Small Business Innovation Research Phase II effort will develop an all-diode laser and fiber optic based, single frequency, sub-nanosecond pulsed laser source...

Ambient light-based optical biosensing platform with smartphone-embedded illumination sensor.

Science.gov (United States)

Park, Yoo Min; Han, Yong Duk; Chun, Hyeong Jin; Yoon, Hyun C

2017-07-15

We present a hand-held optical biosensing system utilizing a smartphone-embedded illumination sensor that is integrated with immunoblotting assay method. The smartphone-embedded illumination sensor is regarded as an alternative optical receiver that can replaces the conventional optical analysis apparatus because the illumination sensor can respond to the ambient light in a wide range of wavelengths, including visible and infrared. To demonstrate the biosensing applicability of our system employing the enzyme-mediated immunoblotting and accompanying light interference, various types of ambient light conditions including outdoor sunlight and indoor fluorescent were tested. For the immunoblotting assay, the biosensing channel generating insoluble precipitates as an end product of the enzymatic reaction is fabricated and mounted on the illumination sensor of the smartphone. The intensity of penetrating light arrives on the illumination sensor is inversely proportional to the amount of precipitates produced in the channel, and these changes are immediately analyzed and quantified via smartphone software. In this study, urinary C-terminal telopeptide fragment of type II collagen (uCTX-II), a biomarker of osteoarthritis diagnosis, was tested as a model analyte. The developed smartphone-based sensing system efficiently measured uCTX-II in the 0-5ng/mL concentration range with a high sensitivity and accuracy under various light conditions. These assay results show that the illumination sensor-based optical biosensor is suitable for point-of-care testing (POCT). Copyright © 2016 Elsevier B.V. All rights reserved.

The CHARA array adaptive optics I: common-path optical and mechanical design, and preliminary on-sky results

Science.gov (United States)

Che, Xiao; Sturmann, Laszlo; Monnier, John D.; ten Brummelaar, Theo A.; Sturmann, Judit; Ridgway, Stephen T.; Ireland, Michael J.; Turner, Nils H.; McAlister, Harold A.

2014-07-01

The CHARA array is an optical interferometer with six 1-meter diameter telescopes, providing baselines from 33 to 331 meters. With sub-milliarcsecond angular resolution, its versatile visible and near infrared combiners offer a unique angle of studying nearby stellar systems by spatially resolving their detailed structures. To improve the sensitivity and scientific throughput, the CHARA array was funded by NSF-ATI in 2011 to install adaptive optics (AO) systems on all six telescopes. The initial grant covers Phase I of the AO systems, which includes on-telescope Wavefront Sensors (WFS) and non-common-path (NCP) error correction. Meanwhile we are seeking funding for Phase II which will add large Deformable Mirrors on telescopes to close the full AO loop. The corrections of NCP error and static aberrations in the optical system beyond the WFS are described in the second paper of this series. This paper describes the design of the common-path optical system and the on-telescope WFS, and shows the on-sky commissioning results.

ASPHERICITY, INTERACTION, AND DUST IN THE TYPE II-P/II-L SUPERNOVA 2013EJ IN MESSIER 74

Energy Technology Data Exchange (ETDEWEB)

Mauerhan, Jon C.; Graham, Melissa L.; Filippenko, Alexei V.; Shivvers, Isaac [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Van Dyk, Schuyler D. [Infrared Processing and Analysis Center, California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Johansson, Joel [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 234 Herzl St., Rehovot (Israel); Hu, Maokai; Wang, Lifan [Department of Physics, Texas A and M University, College Station, TX 77843 (United States); Fox, Ori D., E-mail: mauerhan@astro.berkeley.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

2017-01-10

SN 2013ej is a well-studied core-collapse supernova (SN) that stemmed from a directly identified red supergiant (RSG) progenitor in galaxy M74. The source exhibits signs of substantial geometric asphericity, X-rays from persistent interaction with circumstellar material (CSM), thermal emission from warm dust, and a light curve that appears intermediate between supernovae of Types II-P and II-L. The proximity of this source motivates a close inspection of these physical characteristics and their potential interconnection. We present multiepoch spectropolarimetry of SN 2013ej during the first 107 days and deep optical spectroscopy and ultraviolet through infrared photometry past ∼800 days. SN 2013ej exhibits the strongest and most persistent continuum and line polarization ever observed for a SN of its class during the recombination phase. Modeling indicates that the data are consistent with an oblate ellipsoidal photosphere, viewed nearly edge-on and probably augmented by optical scattering from circumstellar dust. We suggest that interaction with an equatorial distribution of CSM, perhaps the result of binary evolution, is responsible for generating the photospheric asphericity. Relatedly, our late-time optical imaging and spectroscopy show that asymmetric CSM interaction is ongoing, and the morphology of broad H α emission from shock-excited ejecta provides additional evidence that the geometry of the interaction region is ellipsoidal. Alternatively, a prolate ellipsoidal geometry from an intrinsically bipolar explosion is also a plausible interpretation of the data but would probably require a ballistic jet of radioactive material capable of penetrating the hydrogen envelope early in the recombination phase. Finally, our latest space-based optical imaging confirms that the late interaction-powered light curve dropped below the stellar progenitor level, confirming the RSG star’s association with the explosion.

New experimental diffractive-optical data on E.Land's Retinex mechanism in human color vision: Part II

Science.gov (United States)

Lauinger, N.

2007-09-01

A better understanding of the color constancy mechanism in human color vision [7] can be reached through analyses of photometric data of all illuminants and patches (Mondrians or other visible objects) involved in visual experiments. In Part I [3] and in [4, 5 and 6] the integration in the human eye of the geometrical-optical imaging hardware and the diffractive-optical hardware has been described and illustrated (Fig.1). This combined hardware represents the main topic of the NAMIROS research project (nano- and micro- 3D gratings for optical sensors) [8] promoted and coordinated by Corrsys 3D Sensors AG. The hardware relevant to (photopic) human color vision can be described as a diffractive or interference-optical correlator transforming incident light into diffractive-optical RGB data and relating local RGB onto global RGB data in the near-field behind the 'inverted' human retina. The relative differences at local/global RGB interference-optical contrasts are available to photoreceptors (cones and rods) only after this optical pre-processing.

Quantum criticality of geometric phase in coupled optical cavity arrays under linear quench

OpenAIRE

Sarkar, Sujit

2013-01-01

The atoms trapped in microcavities and interacting through the exchange of virtual photons can be modeled as an anisotropic Heisenberg spin-1/2 lattice. We study the dynamics of the geometric phase of this system under the linear quenching process of laser field detuning which shows the XX criticality of the geometric phase in presence of single Rabi frequency oscillation. We also study the quantum criticality for different quenching rate in the presence of single or two Rabi frequencies osci...

Small Galactic H II regions. II. The molecular clouds and star formation

International Nuclear Information System (INIS)

Hunter, D.A.; Thronson, H.A. Jr.; Wilton, C.

1990-01-01

CO maps of molecular clouds associated with 11 small Galactic H II regions are presented and compared with IR images obtained by IRAS. The molecular masses of the clouds are computed and compared with the masses of the stellar content. The mapped clouds have masses of 1000-60,000 solar and are typical of the more numerous, smaller Galactic molecular clouds. All of the clouds have recently made massive OB stars, and many have complex spatial and kinematic structures. The coincidence of IRAS sources and CO peaks suggests that many of the clouds have sites of star formation other than the optically visible H II region. Star-formation efficiencies are uncertain, with values for the clouds ranging from 0.02 to 0.6 with an average value of 0.2. There is no trend of the upper stellar mass limit with Galactic radius and with molecular cloud mass. 53 refs

Investigation of resonant Raman scattering in type II GaAs/AlAs superlattices

International Nuclear Information System (INIS)

Choi, H.

2001-01-01

As a consequence of the band alignment in GaAs/AIAs superlattices (SLs) and the indirect nature of bulk AIAs, quantum confinement can be used to engineer a Type II system. This produces an electron population in the AIAs longitudinal (X z ) or transverse (X xy ) zone-edge states, which is separated in both direct and reciprocal space from the hole population in the GaAs zone-centre (Γ) states. This thesis is an investigation of the electronic and vibrational structure of Type II GaAs/AIAs SLs using theoretical models and spectroscopic techniques, with special emphasis on Type II resonant Raman (RR) scattering. The majority of this thesis concerns short-period GaAs/AIAs SLs with X z as the lowest conduction band state. A model of the SL electronic band structure is presented, including the effects of interband Γ-X z mixing and the X-point camel's back structure. Interband mixing makes Γ-X z radiative transitions observable in photoluminescence (PL) and RR experiments. Phonon-assisted transitions from the X z state are also observed in PL experiments. Several of the participating phonon modes are unambiguously identified, in good agreement with recent reports. This thesis presents the first detailed experimental and theoretical study of Type II RR scattering from the incoming channel of the X z -related Type II bandgap. The X z - related Type II incoming RR spectra in the GaAs optic phonon region are compared with the Γ-related Type I outgoing RR spectra within several theoretical models. Thereby, the mechanisms of the Type II RR scattering, the origins of the RR lineshape and the polarisation dependence, are fully explained, clarifying the spectral features observed in the GaAs zone-centre optic phonon region. The Type II resonance also allows the observation of zone boundary (X-point) phonons from intervalley (IV) scattering. A model of the IV electron-phonon interaction involving X conduction band electrons and zone boundary phonons in Type II SLs is presented

Optical stimulated luminescence (OSL) dating

International Nuclear Information System (INIS)

Banerjee, D.

1999-01-01

Since the pioneering work by Huntley et al. (1985), optical dating is being increasingly recognised as an important technique for establishing a time frame of deposition of sediments (Aitken, 1998). Optical dating differs from thermoluminescence (TL) dating in that visible/infrared light from lasers or LEDs (light-emitting-diodes) is used as a means of stimulation, in contrast to thermal stimulation. It has several advantages over TL dating: (i) the resetting of the OSL (optically stimulated luminescence) clock is more effective than that of TL clock; for sediments transported under water or in other situations where the sediment grains have undergone inhomogeneous bleaching, this property ensures that ages based on optical dating are generally more reliable than TL ages, (ii) the optical dating technique is non-destructive, and multiple readouts of the optical signal is possible; this feature has resulted in the development of single-aliquot and single-grain protocols (Murray and Wintle, 1999; Banerjee et al. 1999), (iii) the sample is not heated as in TL; thus, spurious luminescence is avoided and there is a significant reduction in blackbody radiation. Dating of materials which change phase on heating is also practical, and finally, (iv) thermal quenching of luminescence is negligible, allowing accurate estimation of kinetic parameters using standard techniques and providing access to deep OSL traps. This characteristic may be helpful in extending the limits of optical dating beyond the last 150 ka from a global point of view

4He abundances: Optical versus radio recombination line measurements

Science.gov (United States)

Balser, Dana S.; Rood, Robert T.; Bania, T. M.

2010-04-01

Accurate measurements of the 4He/H abundance ratio are important in constraining Big Bang nucleosynthesis, models of stellar and Galactic evolution, and H ii region physics. We discuss observations of radio recombination lines using the Green Bank Telescope toward a small sample of H ii regions and planetary nebulae. We report 4He/H abundance ratio differences as high as 15-20% between optical and ratio data that are difficult to reconcile. Using the H ii regions S206 and M17 we determine 4He production in the Galaxy to be dY/dZ = 1.71 ± 0.86.

Nanostructured High Performance Ultraviolet and Blue Light Emitting Diodes for Solid State Lighting

Energy Technology Data Exchange (ETDEWEB)

Arto V. Nurmikko; Jung Han

2007-03-31

We report on research results in this project which synergize advanced material science approaches with fundamental optical physics concepts pertaining to light-matter interaction, with the goal of solving seminal problems for the development of very high performance light emitting diodes (LEDs) in the blue and near ultraviolet for Solid State Lighting applications. Accomplishments in the duration of the contract period include (i) new means of synthesizing AlGaN and InN quantum dots by droplet heteroepitaxy, (ii) synthesis of AlGaInN nanowires as building blocks for GaN-based microcavity devices, (iii) progress towards direct epitaxial alignment of the dense arrays of nanowires, (iv) observation and measurements of stimulated emission in dense InGaN nanopost arrays, (v) design and fabrication of InGaN photonic crystal emitters, and (vi) observation and measurements of enhanced fluorescence from coupled quantum dot and plasmonic nanostructures. The body of results is presented in this report shows how a solid foundation has been laid, with several noticeable accomplishments, for innovative research, consistent with the stated milestones.

Polarized electron cyclotron emission in the Tokapole II Tokamak

International Nuclear Information System (INIS)

Sengstacke, M.A.; Dexter, R.N.; Prager, S.C.

1984-06-01

To examine the effect of wall reflections we have measured the polarization of second harmonic cyclotron emission (at omega = 2 omega/sub ce/) in the Tokapole II tokamak both with and without a microwave absorber installed within the field of view of the receiving antenna. Indeed, the local elimination of wall reflections markedly enhances the polarization, as described in section II. Section III describes observations consistent with right-hand cutoff effects and an attempt to infer the electron temperature from cyclotron emission in an optically thin plasma

A New Test of Copper and Zinc Abundances in Late-type Stars Using Ultraviolet Cu II and Zn II Lines

Science.gov (United States)

Roederer, Ian U.; Barklem, Paul S.

2018-04-01

We present new abundances derived from Cu I, Cu II, Zn I, and Zn II lines in six warm (5766 ≤ {T}eff} ≤ 6427 K), metal-poor (‑2.50 ≤ [Fe/H] ≤ ‑0.95) dwarf and subgiant (3.64 ≤ log g ≤ 4.44) stars. These abundances are derived from archival high-resolution ultraviolet spectra from the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope and ground-based optical spectra from several observatories. Ionized Cu and Zn are the majority species, and abundances derived from Cu II and Zn II lines should be largely insensitive to departures from local thermodynamic equilibrium (LTE). We find good agreement between the [Zn/H] ratios derived separately from Zn I and Zn II lines, suggesting that departures from LTE are, at most, minimal (≲0.1 dex). We find that the [Cu/H] ratios derived from Cu II lines are 0.36 ± 0.06 dex larger than those derived from Cu I lines in the most metal-poor stars ([Fe/H] McDonald Observatory of the University of Texas at Austin.

Clinical evaluation of the Non-Contact Tonometer Mark II.

Science.gov (United States)

Chauhan, B C; Henson, D B

1988-09-01

The purpose of this investigation was to test the reliability of the American Optical Non-Contact Tonometer Mark II (NCT II) using the Goldmann Applanation Tonometer (GAT) as the validating instrument. The sample contained 102 consecutive patients from our University Eye Clinic, of whom one-half had 4 NCT II measurements first, followed by 4 GAT measurements; the other one-half had 4 GAT measurements first, followed by 4 NCT II measurements. No significant change in intraocular pressure (IOP) was noted over the measurement sequence with either instrument. There was no significant difference between paired NCT II and GAT readings when the NCT II was used first; however, a highly significant difference between paired readings was obtained when the GAT was used first, indicating that the GAT measurement produced a delayed reduction in the IOP. This effect did not occur with the NCT II. Although the NCT II is shown to have a good overall reliability when compared to the GAT in both protocols, the agreement between any two tonometers may be influenced greatly by the very process of taking a measurement and by the dynamic nature of the IOP.

Electron-impact excitation of Fe II: Effective collision strengths for optically allowed fine-structure transitions

International Nuclear Information System (INIS)

Ramsbottom, C.A.

2009-01-01

In this paper, we present collision strengths and Maxwellian averaged effective collision strengths for the electron-impact excitation of Fe II. We consider specifically the optically allowed lines for transitions from the 3d 6 4s and 3d 7 even parity configuration states to the 3d 6 4p odd parity configuration levels. The parallel suite of Breit-Pauli codes are utilized to compute the collision cross-sections where relativistic effects are included explicitly in both the target and the scattering approximation. A total of 100 LS or 262-jj levels formed from the basis configurations 3d 6 4s, 3d 7 and 3d 6 4p were included in the wavefunction representation of the target, including all doublet, quartet and sextet terms. The Maxwellian averaged effective collision strengths are computed across a wide range of electron temperatures from 100 to 100,000 K, temperatures of importance in astrophysical and plasma applications. A detailed comparison is made with previous works and significant differences were found to occur for some of the transitions considered. We conclude that in order to obtain converged collision strengths and effective collision strengths for these allowed transitions it is necessary to include contributions from partial waves up to L = 50 explicitly in the calculation, and in addition, account for contributions from even higher partial waves through a 'top up' procedure.

Linear and non-linear optics of condensed matter

International Nuclear Information System (INIS)

McLean, T.P.

1977-01-01

Part I - Linear optics: 1. General introduction. 2. Frequency dependence of epsilon(ω, k vector). 3. Wave-vector dependence of epsilon(ω, k vector). 4. Tensor character of epsilon(ω, k vector). Part II - Non-linear optics: 5. Introduction. 6. A classical theory of non-linear response in one dimension. 7. The generalization to three dimensions. 8. General properties of the polarizability tensors. 9. The phase-matching condition. 10. Propagation in a non-linear dielectric. 11. Second harmonic generation. 12. Coupling of three waves. 13. Materials and their non-linearities. 14. Processes involving energy exchange with the medium. 15. Two-photon absorption. 16. Stimulated Raman effect. 17. Electro-optic effects. 18. Limitations of the approach presented here. (author)

Effects of Manganese (Ii Sulphate on Structural, Spectral, Optical, Thermal and Mechanical Properties of L-Alanine Sodium Sulphate Single Crystals

Directory of Open Access Journals (Sweden)

F. Praveena

2017-04-01

Full Text Available New Non-linear Optical materials have been attracting in the research world for their potential applications in emerging opto-electronic technology. The dipolar nature of amino acid leads to peculiar physical and chemical properties, thus making a good candidate for NLO applications. Single crystals of manganese(II sulphate doped L-Alanine sodium sulphate(LASS has been synthesized by slow evaporation technique. Structural property of the grown crystals are characterized by X-ray powder diffraction,FT-IR spectral analysis conforms all the functional groups. Thermogravity (TG and differential themogravimetric (DTA analysis have been performed to study the thermal stability of the crystals. The second harmonic generation efficiency was measured by Kurtz-Perry powder technique. The transmission and absorption of electromagnetic radiation is analysed through UV-VIS spectrum. Microhardness was measured at different applied load to understand the mechanical stability of the crystal.

Macaque accessory optic system: II. Connections with the pretectum

International Nuclear Information System (INIS)

Baleydier, C.; Magnin, M.; Cooper, H.M.

1990-01-01

Connections of the accessory optic system (AOS) with the pretectum are described in the macaque monkey. Injections of tritiated amino acids in the pretectum demonstrate a major contralateral projection to the dorsal (DTN), lateral (LTN), and medial (MTN) terminal nuclei of the AOS and a sparser projection to the ipsilateral LTN. Injections of retrograde tracers, Fast Blue (FB), or wheat germ agglutinin horseradish peroxidase (WGA-HRP) plus nonconjugated horseradish peroxidase (HRP) in the LTN show that the pretectal-LTN projection originates from two nuclei. The main source of pretectal efferents to the LTN is from the pretectal olivary nucleus (OPN) and is entirely contralateral. This projection, which appears unique to primates, originates from the large multipolar cells of the OPN. In addition to this projection, the nucleus of the optic tract (NOT) projects to the ipsilateral LTN, as in nonprimates. Injection of WGA-HRP in the pretectum shows a reciprocal predominantely ipsilateral projection from the LTN to the pretectum. Retinas were observed after injection of FB in the LTN. The retinal ganglion cells projecting to the AOS are mainly distributed near the fovea and in the nasal region of the contralateral eye, suggesting a nasotemporal pattern of decussation. The demonstration of a direct connection between LTN and OPN forces to a reconsideration of the functional role of the AOS. Previous descriptions of luminance responsive cells in the LTN support a possible participation of this nucleus in the control of the pupillary light reflex

Controlled Photon Switch Assisted by Coupled Quantum Dots

Science.gov (United States)

Luo, Ming-Xing; Ma, Song-Ya; Chen, Xiu-Bo; Wang, Xiaojun

2015-01-01

Quantum switch is a primitive element in quantum network communication. In contrast to previous switch schemes on one degree of freedom (DOF) of quantum systems, we consider controlled switches of photon system with two DOFs. These controlled photon switches are constructed by exploring the optical selection rules derived from the quantum-dot spins in one-sided optical microcavities. Several double controlled-NOT gate on different joint systems are greatly simplified with an auxiliary DOF of the controlling photon. The photon switches show that two DOFs of photons can be independently transmitted in quantum networks. This result reduces the quantum resources for quantum network communication. PMID:26095049

Stability and time-domain analysis of the dispersive tristability in microresonators under modal coupling

Science.gov (United States)

Dumeige, Yannick; Féron, Patrice

2011-10-01

Coupled nonlinear resonators have potential applications for the integration of multistable photonic devices. The dynamic properties of two coupled-mode nonlinear microcavities made of Kerr material are studied by linear stability analysis. Using a suitable combination of the modal coupling rate and the frequency detuning, it is possible to obtain configurations where a hysteresis loop is included inside other bistable cycles. We show that a single resonator with two modes both linearly and nonlinearly coupled via the cross-Kerr effect can have a multistable behavior. This could be implemented in semiconductor nonlinear whispering-gallery-mode microresonators under modal coupling for all optical signal processing or ternary optical logic applications.

Stability and time-domain analysis of the dispersive tristability in microresonators under modal coupling

International Nuclear Information System (INIS)

Dumeige, Yannick; Feron, Patrice

2011-01-01

Coupled nonlinear resonators have potential applications for the integration of multistable photonic devices. The dynamic properties of two coupled-mode nonlinear microcavities made of Kerr material are studied by linear stability analysis. Using a suitable combination of the modal coupling rate and the frequency detuning, it is possible to obtain configurations where a hysteresis loop is included inside other bistable cycles. We show that a single resonator with two modes both linearly and nonlinearly coupled via the cross-Kerr effect can have a multistable behavior. This could be implemented in semiconductor nonlinear whispering-gallery-mode microresonators under modal coupling for all optical signal processing or ternary optical logic applications.

Hybrid perovskites: Approaches towards light-emitting devices

KAUST Repository

Alias, Mohd Sharizal

2016-10-06

The high optical gain and absorption of organic-inorganic hybrid perovskites have attracted extensive research for photonic device applications. Using the bromide halide as an example, we present key approaches of our work towards realizing efficient perovskites based light-emitters. The approaches involved determination of optical constants for the hybrid perovskites thin films, fabrication of photonic nanostructures in the form of subwavelength grating reflector patterned directly on the hybrid perovskites as light manipulation layer, and enhancing the emission property of the hybrid perovskites by using microcavity structure. Our results provide a platform for realization of hybrid perovskites based light-emitting devices for solid-state lighting and display applications. © 2016 IEEE.

Surface wave resonance and chirality in a tubular cavity with metasurface design

Science.gov (United States)

Qin, Yuzhou; Fang, Yangfu; Wang, Lu; Tang, Shiwei; Sun, Shulin; Liu, Zhaowei; Mei, Yongfeng

2018-06-01

Optical microcavities with whispering-gallery modes (WGMs) have been indispensable in both photonic researches and applications. Besides, metasurfaces, have attracted much attention recently due to their strong abilities to manipulate electromagnetic waves. Here, combining these two optical elements together, we show a tubular cavity can convert input propagating cylindrical waves into directed localized surface waves (SWs), enabling the circulating like WGMs along the wall surface of the designed tubular cavity. Finite element method (FEM) simulations demonstrate that such near-field WGM shows both large chirality and high local field. This work may stimulate interesting potential applications in e.g. directional emission, sensing, and lasing.

Laser Spectroscopy : XII International Conference

CERN Document Server

Allegrini, Maria; Sasso, Antonio

1996-01-01

This text includes all the recent advances in the field of laser spectroscopy. Major results span from the control of matter by electromagnetic fields (trapping and coding) to high precision measurements on simple atomic systems and to quantum optics with single atoms. It includes a report of the Bose-Einstein condensation achieved by laser-cooling of rubidium atoms. Achievements in the technology of tunable sources, in particular of miniaturized solid state devices, are also reported. Most recent advances in molecular spectroscopy are illustrated with emphasis on "cooled" spectra, clusters and high accuracy frequency references. Topics such as atomic interferometry and microcavity quantum optics are also covered.

Hybrid perovskites: Approaches towards light-emitting devices

KAUST Repository

Alias, Mohd Sharizal; Dursun, Ibrahim; Priante, Davide; Saidaminov, Makhsud I.; Ng, Tien Khee; Bakr, Osman; Ooi, Boon S.

2016-01-01

The high optical gain and absorption of organic-inorganic hybrid perovskites have attracted extensive research for photonic device applications. Using the bromide halide as an example, we present key approaches of our work towards realizing efficient perovskites based light-emitters. The approaches involved determination of optical constants for the hybrid perovskites thin films, fabrication of photonic nanostructures in the form of subwavelength grating reflector patterned directly on the hybrid perovskites as light manipulation layer, and enhancing the emission property of the hybrid perovskites by using microcavity structure. Our results provide a platform for realization of hybrid perovskites based light-emitting devices for solid-state lighting and display applications. © 2016 IEEE.

Triggered lightning return stroke luminosity to 1 km in two optical bands

Science.gov (United States)

Carvalho, F. L.; Uman, M. A.; Jordan, D. M.; Wilkes, R.; Kotovsky, D. A.; Hare, B.

2017-12-01

Measured luminosity waveforms are presented and analyzed as a function of time and channel height using two types of avalanche photodiodes (APDs) for 19 triggered-lightning return strokes during summer 2016. APD type I had an optical bandwidth from 200 nm to 1,000 nm, with peak response at 600 nm (green light), and APD type II had an optical bandwidth from 400 nm to 1,000 nm with a peak response at 800 nm (red light). Ten channel heights ranging from 0 to 1 km (in 100 m increments) were observed by both types of APDs, 20 total, and measured the luminosity in vertical channel slices of approximately 3 m. For APD type I, the return stroke luminosity waveforms generally decay faster following its singular initial peak (IP) than the waveforms recorded by APD type II. APD type II waveforms often exhibit a second maxima (SM) following the IP. Although the wave shapes recorded by each APD type diverge after the IP, the risetime of the initial luminosity wave front preceding the IP for both types of APDs agrees well. The divergence in the luminosity wave shapes following the IP indicates that APD type II is capable of recording spectral lines that are excited or enhanced after the IP more effectively than APD type I. In addition, the SM/IP ratio increases as a function of channel height, indicating that the spectral range better captured by APD type II is more predominant at the top of the channel than at the bottom. Finally, because APD type II responds better to longer wavelengths than APD type I, and because the SM occurs a few microseconds after the IP (at the channel-bottom), we conjecture that the SM following the IP is a consequence of spectral lines excited during the cooling of the channel, following the initial high-temperature/pressure stage. Our data suggests that the initial optical radiation during the return stroke is dominated by ionized atomic species (e.g. four NII lines between 450 and 600 nm, better captured by APD type I) radiated at higher

THE PHOTOMETRIC AND SPECTRAL EVOLUTION OF THE 2008 LUMINOUS OPTICAL TRANSIENT IN NGC 300

International Nuclear Information System (INIS)

Humphreys, Roberta M.; Davidson, Kris; Bond, Howard E.; Bedin, Luigi R.; Bonanos, Alceste Z.; Berto Monard, L. A. G.; Prieto, José L.; Walter, Frederick M.

2011-01-01

The 2008 optical transient in NGC 300 is one of a growing class of intermediate-luminosity transients that brighten several orders of magnitude from a previously optically obscured state. The origin of their eruptions is not understood. Our multi-wavelength photometry and spectroscopy from maximum light to more than a year later provide a record of its post-eruption behavior. We describe its changing spectral energy distribution, the evolution of its absorption- and emission-line spectrum, the development of a bipolar outflow, and the rapid transition from a dense wind to an optically thin ionized wind. In addition to strong, narrow hydrogen lines, the F-type absorption-line spectrum of the transient is characterized by strong Ca II and [Ca II] emission. The very broad wings of the Ca II triplet and the asymmetric [Ca II] emission lines are due to strong Thomson scattering in the expanding ejecta. Post-maximum, the hydrogen and Ca II lines developed double-peaked emission profiles that we attribute to a bipolar outflow. Between approximately 60 and 100 days after maximum, the F-type absorption spectrum, formed in its dense wind, weakened and the wind became transparent to ionizing radiation. We discuss the probable evolutionary state of the transient and similar objects such as SN 2008S and conclude that they were most likely post-red supergiants or post-asymptotic giant branch stars on a blue loop to warmer temperatures when the eruption occurred. These objects are not luminous blue variables.

Light echoes - Type II supernovae

International Nuclear Information System (INIS)

Schaefer, B.E.

1987-01-01

Type II supernovae (SNs) light curves show a remarkable range of shapes. Data have been collected for the 12 Type II SNs that have light curve information for more than four months past maximum. Contrary to previous reports, it is found that (1) the decay rate after 100 days past maximum varies by almost an order of magnitude and (2) the light curve shapes are not bimodally distributed, but actually form a continuum. In addition, it is found that the extinctions to the SNs are related to the light curve shapes. This implies that the absorbing dust is local to the SNs. The dust is likely to be part of a circumstellar shell emitted by the SN progenitor that Dwek (1983) has used to explain infrared echoes. The optical depth of the shell can get quite large. In such cases, it is found that the photons scattered and delayed by reflection off dust grains will dominate the light curve several months after peak brightness. This light echo offers a straightforward explanation of the diversity of Type II SN light curves. 22 references

Thermo-optically induced reorganizations in the main light harvesting antenna of plants. II

DEFF Research Database (Denmark)

Holm, Jens Kai; Varkonyi, Zsuzsanna; Kovacs, Laszlo

2005-01-01

We have investigated the circular dichroism spectral transients associated with the light-induced reversible reorganizations in chirally organized macrodomains of pea thylakoid membranes and loosely stacked lamellar aggregates of the main chlorophyll a/b light harvesting complexes (LHCII) isolated...... from the same membranes. These reorganizations have earlier been assigned to originate from a thermo-optic effect. According to the thermo-optic mechanism, fast local thermal transients due to dissipation of the excess excitation energy induce elementary structural changes in the close vicinity...

Estimation of the specific mass effect in the isotope shifts of energy levels in the optical spectrum of Ba I and Ba II

International Nuclear Information System (INIS)

Pendrill, L.R.

1984-01-01

A graphical method for separating mass and volume effects from purely optical isotope shift data is presented and compared with King's ''bunching'' method. Recent experimental data on isotope shifts for a wide range of spectral lines in the naturally abundant isotopes of Ba I and Ba II are analysed. Some agreement is found with muonic X-ray data concerning the nuclear size for the isotopes 136, 137 and 138, but there is disagreement (over 20%) for the other isotopes. The level isotope shifts are further parameterised in terms of a linear model, and the specific mass effect is decomposed into sums of one-electron and two-electron shift parameters with respect to the inert-gas like ground state of Ba III. (orig.)

Data transmission optical link for LLRF TESLA project part II: application for BER measurements

Science.gov (United States)

Pozniak, Krzysztof T.; Romaniuk, Ryszard S.; Jalmuzna, Wojciech; Olowski, Krzysztof; Perkuszewski, Karol; Zielinski, Jerzy; Kierzkowski, Krzysztof

2006-02-01

It may be predicted now, even assuming a very conservative approach, that the next generation of the Low Level RF control systems for future accelerators will use extensively such technologies like: very fast programmable circuits equipped with DSP, embedded PC and optical communication I/O functionalities, as well as multi-gigabit optical transmission of measurement data and control signals.

Precision Membrane Optical Shell (PMOS) Technology for RF/Microwave to Lightweight LIDAR Apertures, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Membrane Optical Shell Technology (MOST) is an innovative combination of 1) very low areal density (40 to 200g/m2) optically smooth (<20 nm rms), metallic coated...

Infrared Spectra and Optical Constants of Astronomical Ices: II. Ethane and Ethylene

Science.gov (United States)

Hudson, Reggie L.; Gerakines, Perry A.; Moore, M. H.

2014-01-01

Infrared spectroscopic observations have established the presence of hydrocarbon ices on Pluto and other TNOs, but the abundances of such molecules cannot be deduced without accurate optical constants (n, k) and reference spectra. In this paper we present our recent measurements of near- and mid-infrared optical constants for ethane (C2H6) and ethylene (C2H4) in multiple ice phases and at multiple temperatures. As in our recent work on acetylene (C2H2), we also report new measurements of the index of refraction of each ice at 670 nm. Comparisons are made to earlier work where possible, and electronic versions of our new results are made available.

Synchronous characterization of semiconductor microcavity laser beam.

Science.gov (United States)

Wang, T; Lippi, G L

2015-06-01

We report on a high-resolution double-channel imaging method used to synchronously map the intensity- and optical-frequency-distribution of a laser beam in the plane orthogonal to the propagation direction. The synchronous measurement allows us to show that the laser frequency is an inhomogeneous distribution below threshold, but that it becomes homogeneous across the fundamental Gaussian mode above threshold. The beam's tails deviations from the Gaussian shape, however, are accompanied by sizeable fluctuations in the laser wavelength, possibly deriving from manufacturing details and from the influence of spontaneous emission in the very low intensity wings. In addition to the synchronous spatial characterization, a temporal analysis at any given point in the beam cross section is carried out. Using this method, the beam homogeneity and spatial shape, energy density, energy center, and the defects-related spectrum can also be extracted from these high-resolution pictures.

LAST II: Differential temporal responses of macular pigment optical density in patients with atrophic age-related macular degeneration to dietary supplementation with xanthophylls.

Science.gov (United States)

Richer, Stuart; Devenport, Jenny; Lang, John C

2007-05-01

Age-related macular degeneration (ARMD) is the leading cause of vision loss in aging Western societies. The objective of the Lutein Antioxidant Supplementation Trial (LAST) was to determine whether specific dietary interventions increased macular pigment optical density (MPOD) and visual function in patients with atrophic ARMD. The current objective of LAST II is to discern those specific characteristics that increase MPOD, i.e., that might differentiate a responder from a nonresponder. The LAST study was a prospective, 12-month, randomized, double-masked, placebo-controlled trial conducted at an urban midwestern Veterans Administation Hospital from August 1999 to May 2001. Ninety patients with atrophic ARMD entered the study and were assigned randomly to 1 of 3 groups. Patients in group 1 received 10 mg lutein; in group 2, 10 mg lutein in combination with vitamins, minerals, and antioxidants; and in group 3, maltodextrin placebo. Changes in macular MPOD over time were evaluated. Characteristics potentially influencing MPOD included age, weight (body mass index), initial baseline values of macular pigment, and combining xanthophylls with other nutrients. MPOD increased with supplementation and declined slightly without supplementation (regression slopes not equal to zero in supplemented groups, P < 0.02). The highest increases in MPOD over time occurred in patients with lower baseline values of MPOD. Statistically significant increases in MPOD density were observed in the lutein group for patients with baseline MPOD optical density units and up to 0.2 optical density units in the lutein plus antioxidant group. Further analysis found that none of the subjects' eyes in the lowest quartile of baseline MPOD were in the lowest quartile for change in MPOD. Noteworthy is the observation that those individuals with lowest MPOD, and in greatest need of supplementation, were also most likely to benefit from either the lutein or the lutein plus antioxidant

Photo-physical characterization of fluorophore Ru(bpy32+ for optical biosensing applications

Directory of Open Access Journals (Sweden)

E.L. Sciuto

2015-12-01

Full Text Available We studied absorption, emission and lifetime of the coordination compound tris(2,2′-bipyridylruthenium(II fluorophore (Ru(bpy32+ both dissolved in water solutions and dried. Lifetime measurements were carried out using a new detector, the Silicon Photomultiplier (SiPM, which is more sensitive and physically much smaller than conventional optical detectors, such as imager and scanner. Through these analyses and a morphological characterization with transmission electron microscopy, revealed its usability for sensor applications, in particular, as dye in optical DNA-chip technology, a viable alternative to the conventional CY5 fluorophore. The use of Ru(bpy32+ would solve some of the typical disadvantages related to Cy5’s application, such as self-absorption of fluorescence and photobleaching. In addition, the Ru(bpy32+ longer lifetime may play a key role in the definition of new optical DNA-chip. Keywords: Tris(2,2′-bipyridylruthenium(II, Fluorophore, Spectroscopy, Lifetime measurements, SiPM, TEM

Environmentally benign manufacturing of compact disc stampers[Final Phase II report]; FINAL

International Nuclear Information System (INIS)

None

1999-01-01

Optical data storage is currently a$10B/yr. business. With the introduction of the high capacity Digital Versatile Disc (D/D) as well as the continued growth of CD-Audio and CD-ROM worldwide sales of optical data products as a whole are growing at rate of more than 10% per year. In North America, more than 2.5 billion optical discs will be sold in 1998. By 1999, the numbers of optical discs produced for the North American market will grow to almost three billion. The optical disc manufacturing industry is dominated by Asian and European companies (e.g. Sony of Japan and Philips of Netherlands). Prism Corporation has created a process that could significantly improve US competitiveness in the business of optical disc production. The objectives of the Phase II STTR project were to build and test an ion machining system (IMS) for stamper fabrication, prove overall manufacturing system feasibility by fabrication stampers and replicas, and evaluate alternative materials and alternative process parameters to optimize the process. During tie period of the Phase II project Prism Corporation was able to meet these objectives. In the course of doing so, adjustments had been made to better the project and in turn the final product. An ion machining system was designed and built that produced stampers ready for the molding process. Also, many control steps in the manufacturing process were studied to improve the current process and make it even more compatible with the industry standards, fitting seamlessly into current manufacturing lines

Atomic data of Ti II from laser produced Ti plasmas by optical emission spectroscopy

International Nuclear Information System (INIS)

Refaie, A.I.; Farrag, A.A.; El Sharkawy, H.; El Sherbini, T.M.

2005-06-01

In the present study, the emission spectrum of titanium produced from laser induced plasma has been measured at different distances from the target. The Titanium target is irradiated by using the high power Q-switched Nd:YAG laser (λ=1064 nm) that generates energy 750 mJ/pulse of duration rate 6 ns and repetition rate 10 Hz in vacuum and at different distances. The variation of the distance from the target affects the measured plasma parameters, i.e. the electron density, the ion temperature and the velocity distribution. The electron density increases with the increase of the distance from the target. At a distance 0.6 mm from the target it decreases to 2.28·10 16 cm -3 . The temperature increases with the distance from the get until a distance of 1 mm, after that it decreases. It is found that the plasma velocity increases with the distance then it decreases again. Then, Energy levels and transition probabilities for 3d 2 4p →(3d 2 4s + 3d 3 ) lines have been determined by measurement of emission line intensities from an optically thin laser produced plasma of Ti II in vacuum. Calculations with intermediate coupling using Hartree-Fock wave functions have been carried out in order to place the experimental data on an absolute scale and also to evaluate the lifetimes. The plasma parameters in different regions of the plasma plume have been measured and used to obtain further transition probabilities. (author)

Excitation states in type-II ZnSe/BeTe quantum wells

International Nuclear Information System (INIS)

Platonov, A.V.; Kochereshko, V.P.; Yakovlev, D.R.; Zehnder, U.; Ossau, W.; Fisher, F.; Litz, Th.; Waag, A.; Landwehr, G.

1997-01-01

We present an optical investigation of novel heterostructures based on beryllium chalcogenides with a type-I and type-II band alignment. In the type-II quantum well structures (ZnSe/BeTe) we observed a strong exciton transition involving an electron confined in the conduction band well and a hole localized in the valence band barrier (both in ZnSe layer). This transition is drastically broadened by the temperature increase due to enhanced exciton-acoustic phonon interaction. (author)

Experience with the lathe cut Bausch & Lomb Soflens: Part II--Power and optics study.

Science.gov (United States)

Weissman, B A; Levinson, A

1978-04-01

Ten familiar spin cast and ten lathe cut Bausch & Lomb SOFLENS contact lenses were measured as to their power on a lensometer and on an eye. Both quality of the optics and quantitative measurements were considered. Lens flexure and the presence of a fluid lens between the posterior surface of the contact lens and the anterior cornea is indicated for both lenses to explain differences between power of the lens in air and on the eye. The spin cast lens design appears to create a quantitatively larger fluid lens, and one which will add positive optical power to the lens/eye system. Either from this and/or additional factors, the lathe cut lens appears to give improved optical performance both in air and on the eye.

The Affordable Pre-Finishing of Silicon Carbide for Optical Applications, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Large aperture, lightweight optical mirror technologies are critical for the future of lightweight telescopes and their attendant missions to explore the planets in...

Rugged Low Temperature Actuators for Tunable Fabry Perot Optical Filters, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Why are rugged, low temperature actuator materials important? By themselves, they are useless; however, when fabricated into thin films and integrated into optical...

Ageing of the nonlinear optical susceptibility in soft matter

International Nuclear Information System (INIS)

Ghofraniha, N; Conti, C; Leonardo, R Di; Ruzicka, B; Ruocco, G

2007-01-01

We investigate the nonlinear optics response of a colloidal dispersion undergoing dynamics slowing down with age, by using Z-scan and dynamic light scattering measurements. We study the high optical nonlinearity of an organic dye (rhodamine B) dispersed in a water-clay (laponite) suspension. We consider different clay concentrations (2.0-2.6 wt%) experiencing dynamics arrest. We find that (i) the concentration dependent exponential growth of both mean relaxation time and nonlinear absorption coefficient can be individually scaled to a master curve and (ii) the scaling times are the same for the two physical quantities. These findings indicate that the optical nonlinear susceptibility exhibits the same ageing universal scaling behaviour, typical of disordered out of equilibrium systems

THE Fe II EMISSION IN ACTIVE GALACTIC NUCLEI: EXCITATION MECHANISMS AND LOCATION OF THE EMITTING REGION

International Nuclear Information System (INIS)

Marinello, M.; Rodríguez-Ardila, A.; Garcia-Rissmann, A.; Sigut, T. A. A.; Pradhan, A. K.

2016-01-01

We present a study of Fe ii emission in the near-infrared region (NIR) for 25 active galactic nuclei (AGNs) to obtain information about the excitation mechanisms that power it and the location where it is formed. We employ an NIR Fe ii template derived in the literature and find that it successfully reproduces the observed Fe ii spectrum. The Fe ii bump at 9200 Å detected in all objects studied confirms that Lyα fluorescence is always present in AGNs. The correlation found between the flux of the 9200 Å bump, the 1 μm lines, and the optical Fe ii implies that Lyα fluorescence plays an important role in Fe ii production. We determined that at least 18% of the optical Fe ii is due to this process, while collisional excitation dominates the production of the observed Fe ii. The line profiles of Fe ii λ10502, O i λ11287, Ca ii λ8664, and Paβ were compared to gather information about the most likely location where they are emitted. We found that Fe ii, O i and Ca ii have similar widths and are, on average, 30% narrower than Paβ. Assuming that the clouds emitting the lines are virialized, we show that the Fe ii is emitted in a region twice as far from the central source than Paβ. The distance, though, strongly varies: from 8.5 light-days for NGC 4051 to 198.2 light-days for Mrk 509. Our results reinforce the importance of the Fe ii in the NIR to constrain critical parameters that drive its physics and the underlying AGN kinematics, as well as more accurate models aimed at reproducing this complex emission

THE Fe II EMISSION IN ACTIVE GALACTIC NUCLEI: EXCITATION MECHANISMS AND LOCATION OF THE EMITTING REGION

Energy Technology Data Exchange (ETDEWEB)

Marinello, M. [Universidade Federal de Itajubá, Rua Doutor Pereira Cabral 1303, 37500-903, Itajubá, MG (Brazil); Rodríguez-Ardila, A.; Garcia-Rissmann, A. [Laboratório Nacional de Astrofísica, Rua Estados Unidos 154, Itajubá, MG, 37504-364 (Brazil); Sigut, T. A. A. [The University of Western Ontario, London, ON N6A 3K7 (Canada); Pradhan, A. K., E-mail: murilo.marinello@gmail.com [McPherson Laboratory, The Ohio State University, 140 W. 18th Ave., Columbus, OH 43210-1173 (United States)

2016-04-01

We present a study of Fe ii emission in the near-infrared region (NIR) for 25 active galactic nuclei (AGNs) to obtain information about the excitation mechanisms that power it and the location where it is formed. We employ an NIR Fe ii template derived in the literature and find that it successfully reproduces the observed Fe ii spectrum. The Fe ii bump at 9200 Å detected in all objects studied confirms that Lyα fluorescence is always present in AGNs. The correlation found between the flux of the 9200 Å bump, the 1 μm lines, and the optical Fe ii implies that Lyα fluorescence plays an important role in Fe ii production. We determined that at least 18% of the optical Fe ii is due to this process, while collisional excitation dominates the production of the observed Fe ii. The line profiles of Fe ii λ10502, O i λ11287, Ca ii λ8664, and Paβ were compared to gather information about the most likely location where they are emitted. We found that Fe ii, O i and Ca ii have similar widths and are, on average, 30% narrower than Paβ. Assuming that the clouds emitting the lines are virialized, we show that the Fe ii is emitted in a region twice as far from the central source than Paβ. The distance, though, strongly varies: from 8.5 light-days for NGC 4051 to 198.2 light-days for Mrk 509. Our results reinforce the importance of the Fe ii in the NIR to constrain critical parameters that drive its physics and the underlying AGN kinematics, as well as more accurate models aimed at reproducing this complex emission.

Optical and Near-infrared Study of Nova V2676 Oph 2012

Energy Technology Data Exchange (ETDEWEB)

Raj, A. [Korea Astronomy and Space Science Institute, Daejeon, 34055 (Korea, Republic of); Das, R. K. [Department of Astrophysics and Cosmology, S N Bose National Centre for Basic Sciences, Salt Lake, Kolkata 700106 (India); Walter, F. M., E-mail: ashish.raj@iiap.res.in [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States)

2017-02-01

We present optical spectrophotometric and near-infrared (NIR) photometric observations of the nova V2676 Oph covering the period from 2012 March 29 through 2015 May 8. The optical spectra and photometry of the nova have been taken from SMARTS and Asiago; the NIR photometry was obtained from SMARTS and Mt. Abu. The spectra were dominated by strong H i lines from the Balmer series, Fe ii, N i, and [O i] lines in the initial days, typical of an Fe ii type nova. The measured FWHM for the H β and H α lines was 800–1200 km s{sup −1}. There was pronounced dust formation starting 90 days after the outburst. The J − K color was the largest among recent dust-forming novae.

Top-emitting organic light-emitting diodes.

Science.gov (United States)

Hofmann, Simone; Thomschke, Michael; Lüssem, Björn; Leo, Karl

2011-11-07

We review top-emitting organic light-emitting diodes (OLEDs), which are beneficial for lighting and display applications, where non-transparent substrates are used. The optical effects of the microcavity structure as well as the loss mechanisms are discussed. Outcoupling techniques and the work on white top-emitting OLEDs are summarized. We discuss the power dissipation spectra for a monochrome and a white top-emitting OLED and give quantitative reports on the loss channels. Furthermore, the development of inverted top-emitting OLEDs is described.

MHz-level self-sustained pulsation in polymer microspheres on a chip

Directory of Open Access Journals (Sweden)

Zhou-Chen Luo

2014-12-01

Full Text Available We observe MHz-level periodic self-sustained pulsation (SSP in the transmission spectrum of a polydimethylsiloxane (PDMS spherical microcavity on a silicon chip, under a fixed-frequency continuous laser excitation. The SSP results from the strong competition between the thermo-optic and thermal expansion effects of PDMS within the cavity mode volume. The experimental results show good agreement with the theoretical prediction by considering the modification of the thermal expansion coefficient and the temperature distribution within the mode volume.

Regeneration of Optic Nerve

Directory of Open Access Journals (Sweden)

Kwok-Fai So

2011-05-01

Full Text Available The optic nerve is part of the central nervous system (CNS and has a structure similar to other CNS tracts. The axons that form the optic nerve originate in the ganglion cell layer of the retina and extend through the optic tract. As a tissue, the optic nerve has the same organization as the white matter of the brain in regard to its glia. There are three types of glial cells: Oligodendrocytes, astrocytes, and microglia. Little structural and functional regeneration of the CNS takes place spontaneously following injury in adult mammals. In contrast, the ability of the mammalian peripheral nervous system (PNS to regenerate axons after injury is well documented. A number of factors are involved in the lack of CNS regeneration, including: (i the response of neuronal cell bodies against the damage; (ii myelin-mediated inhibition by oligodendrocytes; (iii glial scarring, by astrocytes; (iv macrophage infiltration; and (v insufficient trophic factor support. The fundamental difference in the regenerative capacity between CNS and PNS neuronal cell bodies has been the subject of intensive research. In the CNS the target normally conveys a retrograde trophic signal to the cell body. CNS neurons die because of trophic deprivation. Damage to the optic nerve disconnects the neuronal cell body from its target-derived trophic peptides, leading to the death of retinal ganglion cells. Furthermore, the axontomized neurons become less responsive to the peptide trophic signals they do receive. On the other hand, adult PNS neurons are intrinsically responsive to neurotrophic factors and do not lose trophic responsiveness after axotomy. In this talk different strategies to promote optic-nerve regeneration in adult mammals are reviewed. Much work is still needed to resolve many issues. This is a very important area of neuroregeneration and neuroprotection, as currently there is no cure after traumatic optic nerve injury or retinal disease such as glaucoma, which

What is LAMPF II

International Nuclear Information System (INIS)

Thiessen, H.A.

1982-08-01

The present conception of LAMPF II is a high-intensity 16-GeV synchrotron injected by the LAMPF 800-MeV H - beam. The proton beam will be used to make secondary beams of neutrinos, muons, pions, kaons, antiprotons, and hyperons more intense than those of any existing or proposed accelerator. For example, by taking maximum advantage of a thick target, modern beam optics, and the LAMPF II proton beam, it will be possible to make a negative muon beam with nearly 100% duty factor and nearly 100 times the flux of the existing Stopped Muon Channel (SMC). Because the unique features of the proposed machine are most applicable to beams of the same momentum as LAMPF (that is, < 2 GeV/c), it may be possible to use most of the experimental areas and some of the auxiliary equipment, including spectrometers, with the new accelerator. The complete facility will provide improved technology for many areas of physics already available at LAMPF and will allow expansion of medium-energy physics to include kaons, antiprotons, and hyperons. When LAMPF II comes on line in 1990 LAMPF will have been operational for 18 years and a major upgrade such as this proposal will be reasonable and prudent