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Jason Gray, Kristine A. Bertness, Norman Sanford, Charles T. Rogers
We report on the low-frequency 1/f (flicker) parameter noise displayed by the resonance frequency and resistance of doubly clamped c-axis gallium nitride nanowire (NW) mechanical resonators. The resonators are electrostatically driven and their mechanical
Christopher M. Dodson, Patrick Parkinson, Kristine A. Bertness, Hannah J. Joyce, Laura M. Herz, Norman Sanford, Michael B. Johnston
The first noncontact photoconductivity measurements of gallium nitride nanowires (NWs) are presented, revealing a high crystallographic and optoelectronic quality achieved by use of catalyst-free molecular beam epitaxy. In comparison with bulk material
Rusen Yan, Qin Zhang, Wei Li, Irene G. Calizo, Tian T. Shen, Curt A. Richter, Angela R. Hight Walker, Xuelei X. Liang, David J. Gundlach, Nhan Van Nguyen, Huili G. Xing, Alan Seabaugh
We determined the band alignment of a graphene-oxide-silicon structure using internal photoemission spectroscopy. From the flatband voltage and Dirac voltage we infer a 4.3 10e11 cm-2 negative extrinsic charge present on the graphene surface. Also, we
Kevin O. Knabe, Fabrizio R. Giorgetta, Nathan R. Newbury, Chris Armacost, Michael Radunsky, Sam Crivello, Timothy Day, Paul A. Williams
We demonstrate sub-MHz spectral resolution of N 2O absorption spectra acquired with a swept external-cavity quantum cascade laser (QCL) over 0.87 THz. The QCL frequency is monitored by sum -frequency generation with an optical fiber frequency comb.
David J. Livigni, Nathan A. Tomlin, Christopher L. Cromer, John H. Lehman
A cryogenic radiometer was constructed for direct-substitution optical fiber power measurements. The cavity is intended to operate at the 3 K temperature stage of a dilution refrigerator or 4.2 K stage of a liquid cryostat. The optical fiber is removable
Nathan R. Newbury, Alexander M. Zolot, Esther Baumann, Fabrizio R. Giorgetta, Florian B. Adler, Ian R. Coddington, Kevin O. Knabe, Lora L. Nugent-Glandorf, Paul A. Williams, Scott A. Diddams, Tyler W. Neely
An optical frequency comb based on the output of a mode-locked femtosecond laser can be used in spectroscopic studies and sensing applications. The broad array of frequency modes simultaneously provides high spectral resolution and broad wavelength
Kristine A. Bertness, Norman A. Sanford, John B. Schlager, Alexana Roshko, Todd E. Harvey, Paul T. Blanchard, Matthew D. Brubaker, Andrew M. Herrero, Aric W. Sanders
Catalyst-free growth of GaN nanowires with molecular beam epitaxy produces material of exceptionally high quality with long minority carrier lifetimes and low surface recombination velocity. The nanowires grow by thermodynamic driving forces that enhance
Kevin O. Knabe, Paul A. Williams, Fabrizio R. Giorgetta, Chris Armacost, Michael Radunsky, Nathan R. Newbury
We measure the frequency noise spectrum of a free-running external-cavity quantum cascade laser at 4.5 υm through sum frequency generation with a fiber frequency comb.
We demonstrate a high-accuracy heterodyne measurement system for characterizing the magnitude of the frequency response of high-speed 1.55 µm photoreceivers from 2 MHz to greater than 50 GHz. At measurement frequencies below 2 GHz, we employ a phase-locked
Brian S. Dennis, Vladimir Aksyuk, Michael Haftel, Stefan T. Koev, Girsh Blumberg
It is recognized that surface plasmons (SPs),which can be present on particulate, smooth, or corrugated metallic surfaces, have enormous potential in the fields of novel nano-optical and opto-electronic devices, as well as in spectroscopic, biological, and
This paper gives an overview of measurement techniques used in the THz region of the electromagnetic spectrum, from about 100 GHz to several THz. Currently available components necessary for THz metrology, such as sources, detectors and passives, are
Kristine A. Bertness, Norman A. Sanford, John B. Schlager
We discuss the present state-of-the-art concerning the growth mechanism, optical luminescence and electrical properties for GaN nanowires grown with catalyst-free molecular beam epitaxy. These nanowires are essentially defect-free and display long
Kristine A. Bertness, Jason M. Gray, Norman A. Sanford, Charles T. Rogers
We report on the fabrication, piezoresistive readout, and frequency response of doubly-clamped c-axis gallium nitride (GaN) nanowire (NW) resonators that show mechanical quality factors exceeding 10,000. The devices are fabricated using a combination of
Joseph J. Brown, Kristine A. Bertness, Alicia I. Baca, Bright M. Victor
The use of ALD TiO 2 surface coating improves dielectrophoretic assembly yield of individual GaN nanowires on micro-fabricated structures by as much as 67%. With titanium dioxide coating, individual nanowires were placed across suspended electrode pairs in
The photoresponse of three different photovoltaic Cu(In, Ga)Se 2 (CIGS) samples as well as GaAs and silicon bulk samples is measured using near-field scanning microwave microscopy (NSMM). Modeling predicts light-dependent conductivity values for bulk
Erich N. Grossman, Jonathan D. Chisum, Zoya Popovic
This article describes the theory and design of an ultra-low noise electronic readout circuit for use with room temperature video-rate terahertz imaging arrays. First, the noise characteristics of various imaging detectors, including low resistance
Varun B. Verma, Martin J. Stevens, Kevin L. Silverman, Neville Dias, Akash Garg, James J. Coleman, Richard P. Mirin
We measure the polarization state of the photoluminescence of elliptically shaped lithographically patterned quantum dots fabricated using a wet etching and regrowth technique. We show that the dipole moment of the ground state of elliptical quantum dots
Marla L. Dowell, Christopher L. Cromer, Xiaoyu X. Li, John Bagford, Dan Seibert, John Eric, David Cooper, Steven Comisford, Ernie Cromwell, Richard Bowling
We report comparisons of laser power measurements between the new NIST radiometer, also known as the BB Prime, and the current Air Force standards, known as the BB calorimeter. [1] These measurements were performed using high power laser sources in the Air
Sae Woo Nam, J. A. O'Connor, Michael Tanner, C. M. Natarajan, G. S. Buller, R. J. Warburton, S Miki, Z. Wang, Robert Hadfield
We report on the position-dependent variation in output pulse timing across a superconducting single- photon detector. Our device consists of a single niobium nitride nanowire meander (100 nm width, 4 nm film thickness, 2 mm length). We use a confocal
The National Institute of Standards and Technology (NIST) and the Naval Surface Warfare Center Corona Division (NSWC) have jointly developed a low-level peak-power radiometer (D-ESR) which functions as a transfer standard for measuring laser pulses at
Jeffrey A. Jargon, Xiaoxia Wu, Alan Willner, Loukas Paraschis
We demonstrate a technique of using artificial neural networks trained with parameters derived from delay-tap asynchronous diagrams for optical performance monitoring of phase shift keying (PSK) data signals. We show that asynchronous diagrams from
Kristine A. Bertness, Norman Sanford, Albert Davydov
We characterized the elastic properties of GaN nanowires grown along different crystallographic orientations. In situ transmission electron microscopy tensile tests were conducted using a MEMS-based nanoscale testing system. Complementary atomistic
Esther Baumann, Fabrizio R. Giorgetta, Ian R. Coddington, William C. Swann, Nathan R. Newbury
A coherent dual fiber-comb spectrometer centered at 1.5 µm wavelengths is transferred to 3.4 µm by difference-frequency generation with a 1064 nm cw laser. It is shown that the residual linewidth between the comb teeth at 3.4 µm is resolution-limited to
Kristine A. Bertness, Kevin C. Cossel, F Adler, M J. Thorpe, Jun Ye
Cavity-enhanced direct frequency comb spectroscopy (CE-DFCS) has demonstrated powerful potential for trace-gas detection based on its unique combination of high bandwidth, rapid data acquisition, high sensitivity, and high resolution, which is unavailable
This document describes the calibration service for instruments that measure laser beam diameter. An overview of the measurement procedures, measurement system, and uncertainty analysis is presented. A sample measurement report is included in this document