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Articles 1 - 9 of 9

Full-Text Articles in Engineering

Nanoantenna Array-Induced Fluorescence Enhancement And Reduced Lifetimes, Reuben M. Bakker, V. P. Drachev, Zhengtong Liu, Hsiao-Kuan Yuan, Rasmus H. Pedersen, Alexandra Boltasseva, Jiji Chen, Joseph Irudayaraj, Alexander V. Kildishev, V. M. Shalaev Dec 2008

Nanoantenna Array-Induced Fluorescence Enhancement And Reduced Lifetimes, Reuben M. Bakker, V. P. Drachev, Zhengtong Liu, Hsiao-Kuan Yuan, Rasmus H. Pedersen, Alexandra Boltasseva, Jiji Chen, Joseph Irudayaraj, Alexander V. Kildishev, V. M. Shalaev

Birck and NCN Publications

Enhanced fluorescence is observed from dye molecules interacting with optical nanoantenna arrays. Elliptical gold dimers form individual nanoantennae with tunable plasmon resonances depending upon the geometry of the two particles and the size of the gap between them. A fluorescent dye, Rhodamine 800, is uniformly embedded in a dielectric host that coats the nanoantennae. The nanoantennae act to enhance the dye absorption. In turn, emission from the dye drives the plasmon resonance of the antennae; the nanoantennae act to enhance the fluorescence signal and change the angular distribution of emission. These effects depend upon the overlap of the plasmon resonance …


Atomic-Layer-Deposited Al2o3/Gaas Metal-Oxide-Semiconductor Field-Effect Transistor On Si Substrate Using Aspect Ratio Trapping Technique, Y Q. Wu, M Xu, P. D. Ye, Z Cheng, J Li, J Park, J Hydrick, J Bai, M Carroll, J G. Fiorenza, A Lochtefeld Dec 2008

Atomic-Layer-Deposited Al2o3/Gaas Metal-Oxide-Semiconductor Field-Effect Transistor On Si Substrate Using Aspect Ratio Trapping Technique, Y Q. Wu, M Xu, P. D. Ye, Z Cheng, J Li, J Park, J Hydrick, J Bai, M Carroll, J G. Fiorenza, A Lochtefeld

Birck and NCN Publications

High quality GaAs epilayers grown by metal-organic chemical vapor deposition are demonstrated on a SiO2-patterned silicon substrate using aspect ratio trapping technique, whereby threading dislocations from lattice mismatch are largely reduced via trapping in SiO2 trenches during growth. A depletion-mode metal-oxide-semiconductor field-effect transistor (MOSFET) is demonstrated on a n-doped GaAs channel with atomic-layer deposited Al2O3 as the gate oxide. The 10 mu m gate length transistor has a maximum drain current of 88 mA/mm and a transconductance of 19 mS/mm. The surface mobility estimated from the accumulation drain current has a peak value of similar to 500 cm(2)/Vs, which is …


Optical Hyperspace For Plasmons: Dyakonov States In Metamaterials, Zubin Jacob, Evgenii E. Narimanov Dec 2008

Optical Hyperspace For Plasmons: Dyakonov States In Metamaterials, Zubin Jacob, Evgenii E. Narimanov

Birck and NCN Publications

We show that the subdiffraction imaging behavior observed in the magnifying superlens experiment, [Smolyaninov , Science 317, 1699 (2007)] is due to the hyperbolic dispersion of Dyakonov plasmons supported by the device. These states which are a special case of Dyakonov surface waves [Dyakonov, Sov. Phys. JETP 67, 714 (1988)] exist at the interface of a metal and an anisotropic dielectric giving rise to plasmon beams on resonance. Furthermore, we describe how the unique properties of metamaterial Dyakonov plasmons can be tailored for plasmonic devices.


Hydrodynamic Loading Of Microcantilevers Oscillating Near Rigid Walls, Ryan C. Tung, Jana Anirban, Arvind Raman Dec 2008

Hydrodynamic Loading Of Microcantilevers Oscillating Near Rigid Walls, Ryan C. Tung, Jana Anirban, Arvind Raman

Birck and NCN Publications

The vibrations of microcantilevers in atomic force microscopes (AFMs) or radio frequency (RF) switches are strongly influenced by the viscous hydrodynamics of the surrounding fluid in the vicinity of a rigid wall. While prior efforts to model this hydrodynamic loading have focused on squeeze film damping effects at high Knudsen and squeeze numbers, the regimes of low Knudsen and squeeze numbers are also very important for which squeeze film models need to be discarded in favor of unsteady Stokes hydrodynamics. We extend the work of Green and Sader [Phys Fluids 17, 073102 (2005); J. Appl. Phys. 98, 114913 (2005)] and …


Transformation Optics: Approaching Broadband Electromagnetic Cloaking, Alexander V. Kildishev, W Cai, U K. Chettiar, V. M. Shalaev Nov 2008

Transformation Optics: Approaching Broadband Electromagnetic Cloaking, Alexander V. Kildishev, W Cai, U K. Chettiar, V. M. Shalaev

Birck and NCN Publications

An approach to broadband cloaking of light waves is analysed for a simplified case of a scaling transformation for a general cylindrical coordinate system. The proposed approach requires metamaterials with specifically engineered dispersion. The restriction on the signs of gradients in the dispersion dependencies of the dielectric permittivity and the magnetic permeability for different operational wavelengths is revealed and is shown to cause difficulties unless additional gain-assisted compensation for losses or electromagnetically induced transparency is introduced in the cloaking system.


Solutions In Folded Geometries, And Associated Cloaking Due To Anomalous Resonance, Graeme W. Milton, Nicolae-Alexandru P. Nicorovici, Ross C. Mcphedran, Kirill Cherednichenko, Zubin Jacob Nov 2008

Solutions In Folded Geometries, And Associated Cloaking Due To Anomalous Resonance, Graeme W. Milton, Nicolae-Alexandru P. Nicorovici, Ross C. Mcphedran, Kirill Cherednichenko, Zubin Jacob

Birck and NCN Publications

Solutions for the fields in a coated cylinder where the core radius is bigger than the shell radius are seemingly unphysical, but can be given a physical meaning if one transforms to an equivalent problem by unfolding the geometry. In particular, the unfolded material can act as an impedance matched hyperlens, and as the loss in the lens goes to zero finite collections of polarizable line dipoles lying within a critical region surrounding the hyperlens are shown to be cloaked having vanishingly small dipole moments. This cloaking, which occurs both in the folded geometry and the equivalent unfolded one, is …


Bright-Field Analysis Of Phi29 Dna Packaging Motor Using A Magnetomechanical System, Chun-Li Chang, Hui Zhang, Dan Shu, Peixuan Guo, Cagri A. Savran Oct 2008

Bright-Field Analysis Of Phi29 Dna Packaging Motor Using A Magnetomechanical System, Chun-Li Chang, Hui Zhang, Dan Shu, Peixuan Guo, Cagri A. Savran

Birck and NCN Publications

We report a simple and robust magnetomechanical system for direct visual observation of the DNA packaging behavior of the bacteriophage phi29 in real time. The system comprises a micron-sized magnetic bead attached to the free end of the viral DNA, a magnet and a bright-field microscope. We show that the phi29 DNA packaging activity can be observed and dynamically analyzed at the single molecular level in bright field with a relatively simple system. With this system we also visually demonstrate the phi29 motor transporting a cargo 10 000 times the viral size.


Structures And Energetics Of Si Nanotubes From Molecular Dynamics And Density Functional Theory, Amritanshu Palaria, Gerhard Klimeck, Alejandro Strachan May 2008

Structures And Energetics Of Si Nanotubes From Molecular Dynamics And Density Functional Theory, Amritanshu Palaria, Gerhard Klimeck, Alejandro Strachan

Birck and NCN Publications

We use molecular dynamics (MD) with a first principles-based force field (ReaxFF) and density functional theory (DFT) to predict the atomic structure, energetics and elastic propoerties of Si nanotubes. We find various low-energy and low-symmetry hollow structures with external diameters of about 1 nm. These are the most stable structures in this small-diameter regime reported so far and exhibit properties very different from the bulk. While the cohesive energies of the four most stable nanotubes reported here are similar (from 0.638 to 0.697 eV above bulk Si), they have disparate Young's moduli (from 72 to 123 GPa).


Nanopatterning Using Nsom Probes Integrated With High Transmission Nanoscale Bowtie Aperture, Nicholas Murphy-Dubay, Liang Wang, Edward C. Kinzel, Sreemanth Mv Uppuluri, Xianfan Xu Feb 2008

Nanopatterning Using Nsom Probes Integrated With High Transmission Nanoscale Bowtie Aperture, Nicholas Murphy-Dubay, Liang Wang, Edward C. Kinzel, Sreemanth Mv Uppuluri, Xianfan Xu

Birck and NCN Publications

Nanoscale ridge aperture antennas have been shown to have high transmission efficiency and confined nanoscale radiation in the near field region compared with regularly-shaped apertures. The radiation enhancement is attributed to the fundamental electric-magnetic field propagating in the TE10 mode concentrated in the gap between the ridges. This paper reports experimental demonstration of field enhancement using such ridge antenna apertures in a bowtie shape for the manufacture of nanometer size structures using an NSOM (near field scanning optical microscopy) probe integrated with nanoscale bowtie aperture. Consistent lines with width of 59 nm and as small as 24 nm have be …