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Electronics

Optoelectronics

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Displaying 101 - 125 of 200

Passive terahertz camera for standoff security screening

July 1, 2010
Author(s)
Erich N. Grossman, Charles Dietlein
We describe the construction and performance of a passive, real-time terahertz camera based on a modular, 64-element linear array of cryogenic hotspot microbolometers. A reflective conical scanner sweeps out a 2 m ×4 m(vertical × horizontal) field of view

Dark pulse quantum dot diode laser

June 7, 2010
Author(s)
Mingming M. Feng, Kevin L. Silverman, Richard P. Mirin, Steven T. Cundiff
We describe an operating regime for passively mode-locked quantum dot diode laser where the output consists of a train of dark pulses, i.e., intensity dips on a continuous background. We show that a dark pulse train is a solution to the master equation for

Why are we concerned with large covariance matrices?

June 1, 2010
Author(s)
Paul D. Hale, Andrew M. Dienstfrey, Chih-Ming Wang
In order to promote discussion, we outline the two different paradigms for propagating uncertainties from the various waveform measurement impairments to the waveform parameters. The first method propagates uncertainty from the impairments directly to a

Bilateral comparison of power measurement standards for KrF lasers between PTB and NIST

May 2, 2010
Author(s)
Marla L. Dowell, Christopher L. Cromer, Darryl A. Keenan, Stefan Kuck, Friedhelm Brandt
We report results of the first bilateral laser power comparison for 248-nm KrF excimer lasers accomplished by the National Metrology Institutes of Germany (Physikalisch-Technische Bundesanstalt, PTB) and of the United States of America (National Institute

Waveform metrology and a quantitative study of regularized deconvolution

May 1, 2010
Author(s)
Paul D. Hale, Andrew M. Dienstfrey
We present methodology and preliminary results of a Monte-Carlo simulation to perform a quantified analysis of regularized deconvolution in the context of full waveform metrology. We analyze the behavior of different regularized inversion methods with

Tensile measurement of single crystal gallium nitride nanowires on MEMS test stages

April 18, 2010
Author(s)
J. J. Brown, A. I. Baca, Kristine A. Bertness, D. A. Dikin, R. S. Ruoff, Victor M. Bright
This paper reports the first direct tensile tests on nearly defect free, n-type (Si-doped) gallium nitride single crystal nanowires. Here, for the first time, nanowires have been integrated with actuated, active microelectromechanical (MEMS) structures

Steady-state and transient photoconductivity in c-axis GaN nanowires grown by nitrogen-plasma-assisted molecular beam epitaxy

February 12, 2010
Author(s)
Norman A. Sanford, Paul T. Blanchard, Kristine A. Bertness, Lorelle Mansfield, John B. Schlager, Aric W. Sanders, Alexana Roshko, Beau Burton, Steven George
Analysis of steady-state and transient photoconductivity measurements at room temperature performed on c-axis oriented GaN nanowires yielded estimates of free carrier concentration, drift, mobility, surface band bending, and surface capture coefficient for

Relative Photon-to-Carrier Efficiencies of Alternating Nanolayers of Zinc Phthalocyanine and C60 Multilayer Films Assessed by Time-Resolved Terahertz Spectroscopy

October 1, 2009
Author(s)
Okan Esenturk, Joseph S. Melinger, Paul A. Lane, Edwin J. Heilweil
Alternating multi-layer and 1:1 blended films of zinc phthalocyanine (ZnPc)and buckminsterfullerene (C60) were investigated as model active layers for solar cells by Time-Resolved Terahertz Spectroscopy (TRTS). Relative photon-to-carrier efficiencies 2

Traceable waveform calibration with a covariance-based uncertainty analysis

October 1, 2009
Author(s)
Paul D. Hale, Dylan F. Williams, Andrew M. Dienstfrey, Arkadiusz C. Lewandowski, Tracy S. Clement, Darryl A. Keenan
We describe a method for calibrating the voltage that a step-like pulse generator produces at a load at every time point in themeasured waveform. The calibration includes an equivalent-circuit model of the generator that can be used to determine how the

Optical performance monitoring of PSK Data Channels using artificial neural networks trained with parameters derived from delay-tap asynchronous diagrams via balanced detection

September 20, 2009
Author(s)
Jeffrey A. Jargon, Xiaoxia Wu, Zhensheng Jia, Loukas Paraschis, Ronald Skoog, Alan Willner
We demonstrate a technique of using artificial neural networks for optical performance monitoring of PSK data signals. Parameters for training are derived from delay-tap asynchronous diagrams using balanced detection. We also compare the results with the

Applications of artificial neural networks in optical performance monitoring

August 15, 2009
Author(s)
Jeffrey A. Jargon, Xiaoxia Wu, Ronald Skoog, Loukas Paraschis, Alan Willner
Applications using artificial neural networks (ANNs) for optical performance monitoring (OPM) are proposed and demonstrated. Simultaneous identification of optical signal-to-noise-ratio (OSNR), chromatic dispersion (CD), and polarization-mode-dispersion

Long distance frequency transfer through an optical carrier

August 2, 2009
Author(s)
Paul A. Williams
Fiber optic networks are an attractive means for the remote distribution of highly stable frequencies from optical clocks. The highest performance is achieved by use of the frequency of the optical carrier itself as the transfer frequency. We will review

Lateral variations in self-assembled InGaAs quantum dot distributions

June 26, 2009
Author(s)
Alexana Roshko, Todd E. Harvey, Brittany L. Hyland, Lehman Y. Susan, Keith D. Cobry
The lateral uniformity of self-assembled InGaAs quantum dots grown by molecular beam epitaxy(MBE) was assessed as a function of growth conditions. Variations in the dot density and height were determined from atomic force micrographs. Growth rate had a

Projector flux from color primaries

May 2, 2009
Author(s)
Edward F. Kelley
A standard methodology exists for estimating the flux from front projection displays by sampling the projected illuminance of a white source signal. With the advent and use of white projection primaries, a dramatic increase in flux can be achieved over the

Character contrast under uniform ambient conditions

May 1, 2009
Author(s)
Edward F. Kelley, John Penczek, Paul A. Boynton
The measurement of small-area black regions on a white screen (such as a character stroke) can be subject to large errors because of veiling glare in the detector. Using replica masks can enable more accurate measurements of small-area-black and character

Electron Microscope Study of Strain in InGaN Quantum Wells in GaN Nanowires

April 1, 2009
Author(s)
Roy H. Geiss, David T. Read
GaN nanowires with InGaN quantum wells (QW) were grown on heated Si(111) substrates by molecular beam epitaxy (MBE) using elemental Ga and In and a radio-frequency-plasma N2 source. The growth procedures and the morphology of these nanowires have been

EEEL Technical Accomplishments

March 30, 2009
Author(s)
Erik M. Secula
This document describes the technical work of the Electronics and Electrical Engineering Laboratory. In this report, you will find that EEEL researchers are developing the world's most advanced sensors, providing advanced gamma ray imagers for astronomical
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