Search Results - (Author, Cooperation:M. Seto)
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1Latest Papers from Table of Contents or Articles in PressS. D. Wong ; M. Srnec ; M. L. Matthews ; L. V. Liu ; Y. Kwak ; K. Park ; C. B. Bell, 3rd ; E. E. Alp ; J. Zhao ; Y. Yoda ; S. Kitao ; M. Seto ; C. Krebs ; J. M. Bollinger, Jr. ; E. I. Solomon
Nature Publishing Group (NPG)
Published 2013Staff ViewPublication Date: 2013-07-23Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsKeywords: Biocatalysis ; Halogenation ; Hydroxylation ; Iron/*chemistry ; Oxidoreductases/*chemistry/metabolism ; Pseudomonas syringae/enzymologyPublished by: -
2Articles: DFG German National LicensesDeri, R. J. ; Shahar, A. ; Colas, E. ; Thurston, R. N. ; Tomlinson, W. J. ; Yi-Yan, A. ; Seto, M.
Woodbury, NY : American Institute of Physics (AIP)
Published 1990Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: We demonstrate a novel waveguide structure for realization of integrated optics with compact waveguide bends (radii≈1 mm), low propagation loss (0.45 dB/cm), and large guide dimensions (5 μm width) to facilitate input coupling. Experimental results using single-mode GaAs/AlGaAs heterostructure guides at 1.52 μm wavelength are presented.Type of Medium: Electronic ResourceURL: -
3Articles: DFG German National LicensesDeri, R. J. ; Doldissen, W. ; Hawkins, R. J. ; Bhat, R. ; Soole, J. B. D. ; Schiavone, L. M. ; Seto, M. ; Andreadakis, N. ; Silberberg, Y. ; Koza, M. A.
Woodbury, NY : American Institute of Physics (AIP)
Published 1991Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: We demonstrate vertical integration of InGaAs mesa photodiodes with InGaAsP rib waveguides employing an intermediate optical impedance matching layer. The diode length necessary for 90% light absorption at 1.52 μm wavelength was 42 μm, a threefold reduction in diode length with respect to previous work employing similar waveguides without a matching layer. The quantum efficiency was observed to be almost independent of the optical wavelength and polarization. The influence of spatial transient intensity redistribution effects on these devices is investigated in detail.Type of Medium: Electronic ResourceURL: -
4Articles: DFG German National LicensesStaff View
ISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: We report on a resonant cavity photodiode with a Si/SiGe Bragg mirror grown by low temperature chemical vapor deposition suitable for short wavelength detection around 600–700 nm. The presence of Fabry-Pérot oscillations in the spectral response of the photodiode are indicative of its wavelength selectivity. © 1998 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
5Articles: DFG German National LicensesShahar, A. ; Tomlinson, W. J. ; Yi-Yan, A. ; Seto, M. ; Deri, R. J.
Woodbury, NY : American Institute of Physics (AIP)
Published 1990Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: Using a novel dynamic etch mask technique and wet chemical etchants, we have produced semiconductor structures with tapered thicknesses, with horizontal slope angles as small as 0.9°. With this technique we have fabricated GaAs/GaAlAs rib optical waveguides in which the etch depth tapered from 0.2 to 1.0 μm over a distance of 50 μm, resulting in a 2× change in mode size, with an excess taper loss of less than 0.2 dB. The technique is capable of producing tapers in different orientations, at arbitrary locations on a sample, and appears to be useful for a wide variety of materials systems and devices.Type of Medium: Electronic ResourceURL: -
6Articles: DFG German National LicensesCox, H. M. ; Lin, P. S. ; Yi-Yan, A. ; Kash, K. ; Seto, M. ; Bastos, P.
Woodbury, NY : American Institute of Physics (AIP)
Published 1989Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: We propose and demonstrate a technique for artifically bunching the atomic steps on a vicinal substrate to form supersteps of almost arbitrary height. The process involves the etching of a grating of parallel grooves on the surface of a vicinal substrate followed by epitaxial growth that fills the grooves. Steps of height proportional to the period of the grating and the substrate misorientation angle are formed. The technique is demonstrated on a macroscopic scale for the InP/InGaAs material system using chloride transport vapor levitation epitaxy, resulting in InGaAs wire-like structures confined both horizontally and vertically by InP. The growth of quantum wires and laterally periodic superlattices should be possible using this technique with proper scaling of parameters.Type of Medium: Electronic ResourceURL: -
7Articles: DFG German National LicensesLo, Y. H. ; Deri, R. J. ; Harbison, J. ; Skromme, B. J. ; Seto, M. ; Hwang, D. M. ; Lee, T. P.
Woodbury, NY : American Institute of Physics (AIP)
Published 1988Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: The GaAs-on-InP heteroepitaxial waveguides are demonstrated for the first time using molecular beam epitaxy. A propagation loss of 9.3 dB/cm was obtained for waveguides grown on a 3° off (100) InP substrate. Compared to the 16 dB/cm loss for waveguides on (100) InP substrates, the waveguides on misoriented InP substrates exhibited a significantly lower loss. Based on photoluminescence studies, we attribute the propagation loss in both samples mainly to optical absorption by crystal defects. Defect densities of 4×1017 cm−3 and 2×1017 cm−3 are estimated for material on (100) and 3° off (100) substrates, respectively. Such heteroepitaxial waveguides may have applications in long-wavelength photonic integrated circuits.Type of Medium: Electronic ResourceURL: -
8Articles: DFG German National LicensesDeri, R. J. ; Kapon, E. ; Bhat, R. ; Seto, M. ; Kash, K.
Woodbury, NY : American Institute of Physics (AIP)
Published 1989Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: Propagation losses as low as 0.24±0.06 dB/cm are demonstrated for single-mode, GaInAs/InP multiple quantum well rib waveguides at 1.52 μm wavelength. We show that reproducibly low losses (≤0.6 dB/cm for rib widths ≥3 μm) can be maintained over a large chip area (9.4×5 mm2). Origins of the loss are discussed.Type of Medium: Electronic ResourceURL: -
9Articles: DFG German National LicensesSeto, M. ; Shahar, A. ; Deri, R. J. ; Tomlinson, W. J. ; Yi-Yan, A.
Woodbury, NY : American Institute of Physics (AIP)
Published 1990Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: Singe-mode optical waveguides have been fabricated with a saturated bromine water etchant using single-heterostructure GaAs/AlGaAs epitaxial material, with propagation losses as low as 0.6 dB/cm for 1.66 μm deeply etched ribs (Δneff(approximately-equal-to)2.4) and losses below 0.2 dB/cm for 0.23 μm shallowly etched ribs (Δneff =0.0067), measured at λ=1.5 μm.Type of Medium: Electronic ResourceURL: -
10Articles: DFG German National LicensesColas, E. ; Yi-Yan, A. ; Bhat, R. ; Seto, M. ; Deri, R. J.
Woodbury, NY : American Institute of Physics (AIP)
Published 1989Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: We demonstrate how an adequate choice of growth conditions and GaAs/AlGaAs superlattice series leads to a desired refractive index profile and to confinement of light at the cusp of a planarized structure over a previously photolithographically etched groove. Waveguiding at 1.52 μm wavelength with measured propagation losses of 1.5 dB/cm was obtained in these structures. The effect of growth parameters is discussed and potential applications of this concept to other structures suitable for guided-wave devices are proposed.Type of Medium: Electronic ResourceURL: -
11Articles: DFG German National LicensesDeri, R. J. ; Kapon, E. ; Harbison, J. P. ; Seto, M. ; Yun, C. P. ; Florez, L. T.
Woodbury, NY : American Institute of Physics (AIP)
Published 1988Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: We demonstrate a low-loss semiconductor optical waveguide phase modulator for the 1.5 μm wavelength region. The device, based on a p-i-n diode/heterostructure waveguide, utilizes a novel epilayer structure to reduce propagation losses associated with doped electrode layers. Propagation loss below 1 dB/cm, significantly lower than previously reported values for conventional semiconductor waveguide phase modulators, was achieved without sacrificing modulator efficiency.Type of Medium: Electronic ResourceURL: -
12Articles: DFG German National LicensesBrunthaler, G. ; Seto, M. ; Stöger, G. ; Köhler, K.
Woodbury, NY : American Institute of Physics (AIP)
Published 1994Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: The achievable two-dimensional (2D) electron concentration in a δ-doped quantum well depends on the Al content in the doping layer and is considerably lower than the nominal doping concentration. This behavior has been so far attributed to different incorporation probabilities of Si atoms depending upon the Al content. In this work, we show instead that the energy levels of the DX center together with the Coulomb interaction account for this behavior. We present calculations of the DX center density of states which are broadened by the Coulomb interaction and show that the estimated 2D carrier concentrations agree well with experiment. © 1994 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
13Articles: DFG German National LicensesStaff View
ISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: We present self-consistent calculations of the energy levels in an asymmetric coupled quantum-well structure coupled to a CO2 laser source which is nearly resonant with an intersubband transition. Solving Schrödinger's and Poisson's equations concurrently with a set of rate equations, it is shown that intrinsic optical bistability can be achieved. The bistability arises from charge transfer and a subsequent, self-consistent shift of the energy levels which feeds back to the absorption rate. Using realistic parameters, an on-off intensity ratio of 4:1 at switching powers of a few 100 kW/cm2 is predicted at about 10-μm wavelength.Type of Medium: Electronic ResourceURL: -
14Articles: DFG German National LicensesSeto, M. ; Helm, M. ; Moussa, Z. ; Boucaud, P. ; Julien, F. H. ; Lourtioz, J.-M. ; Nützel, J. F. ; Abstreiter, G.
Woodbury, NY : American Institute of Physics (AIP)
Published 1994Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: The observation of infrared second-harmonic generation in asymmetric Si/SiGe p-doped quantum wells is reported. The generated signal stems entirely from valence intersubband transitions, since bulk Si, with an inversion symmetric crystal structure, has a zero second-order susceptibility. The experiments were performed using a Q-switched CO2 laser operating at 10.56 μm and give a nonlinear susceptibility of 5×10−8 m/V. © 1994 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
15Articles: DFG German National LicensesSeto, M. ; Rochefort, C. ; de Jager, S. ; Hendriks, R. F. M. ; 't Hooft, G. W. ; van der Mark, M. B.
Woodbury, NY : American Institute of Physics (AIP)
Published 1999Staff ViewISSN: 1077-3118Source: AIP Digital ArchiveTopics: PhysicsNotes: We show that the leakage current through a metal–semiconductor–metal photodetector can be reduced by placing a thin interfacial silicon dioxide layer between the Schottky metal and the silicon substrate. We measure a factor 5.2 reduction in leakage-current density to 18 μA/cm2 at 5 V, a weaker increase in dark current with bias, and a factor 3.5 improvement in photoresponsivity to 0.39 A/W. We do not observe any noticeable reduction in device speed using this interfacial oxide. © 1999 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
16Articles: DFG German National LicensesStaff View
ISSN: 0006-291XSource: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: BiologyChemistry and PharmacologyPhysicsType of Medium: Electronic ResourceURL: -
17Articles: DFG German National LicensesStaff View
ISSN: 0922-338XSource: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Process Engineering, Biotechnology, Nutrition TechnologyType of Medium: Electronic ResourceURL: -
18Articles: DFG German National LicensesStaff View
ISSN: 0014-5793Keywords: Down-regulation ; Myosin light chain ; Protein kinase C ; Smooth muscle cell line ; StaurosporineSource: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: BiologyChemistry and PharmacologyPhysicsType of Medium: Electronic ResourceURL: -
19Articles: DFG German National LicensesStaff View
ISSN: 0040-4039Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Chemistry and PharmacologyType of Medium: Electronic ResourceURL: -
20Articles: DFG German National LicensesStaff View
ISSN: 0031-9422Keywords: Compositae ; Rhynchospermum verticillatum ; ent-clerodane diterpenoids ; rhynchosperin A ; rhynchosperin B ; rhynchosperin C ; rhynchospermoside A ; rhynchospermoside B.Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: BiologyChemistry and PharmacologyType of Medium: Electronic ResourceURL: