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Search Publications by: Robert Schwall (Assoc)

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Displaying 26 - 50 of 58

A High Resolution High-Sensitivity Standoff Imaging System at 350 GHz

May 23, 2011
Author(s)
Daniel T. Becker, Cale Gentry, James A. Beall, Hsiao-Mei Cho, William Duncan, Gene C. Hilton, Kent D. Irwin, Peter J. Lowell, Michael D. Niemack, Nicholas G. Paulter Jr., Carl D. Reintsema, Francis J. Schima, Robert E. Schwall, Peter Ade, Carole Tucker, Simon Dicker, Halpern Mark
Millimeter wavelength radiation holds promise for detection of security threats at a distance, including suicide bomb belts and maritime threats in poor weather conditions. The sensitivity provided by superconducting Transition-Edge-Sensor (TES) bolometers

Practical Operation of Cryogen-free Programmable Josephson Voltage Standards

February 17, 2011
Author(s)
Robert E. Schwall, David Zilz, Jeffrey Power, Charles J. Burroughs, Paul D. Dresselhaus, Samuel P. Benz
Cryogen-free operation is rapidly becoming the preferred implementation of programmable Josephson voltage standard (PJVS) systems. There are strong operational incentives for using the smallest possible cryocooler in order to minimize acoustic noise

A 350-GHz high-resolution high-sensitivity passive video imaging system

April 27, 2010
Author(s)
Daniel T. Becker, James A. Beall, Hsiao-Mei Cho, William Duncan, Kent D. Irwin, Gene C. Hilton, Robert D. Horansky, Peter J. Lowell, Michael D. Niemack, Nicholas G. Paulter Jr., Carl D. Reintsema, Francis J. Schima, Robert E. Schwall, Ki W. Yoon, Peter Ade, Carole Tucker, Simon Dicker, Mark Halpern
We are developing a 350 GHz cryogenic passive video imaging system. This demonstration system uses 800 photon-noise-limited superconducting transition edge sensor bolometers. It will image a 1 m x 1 m area at a standoff distance of 16 m to a resolution of

Time-of-flight mass spectrometry with latching Nb meander detectors

June 1, 2009
Author(s)
Brian Estey, James A. Beall, Gene C. Hilton, Kent D. Irwin, Daniel R. Schmidt, Joel N. Ullom, Robert E. Schwall
Mass Spectrometry is widely used for protein characterization, structural virology, drug discovery, and clinical chemistry. However the detection efficiency of existing detectors for mass spectrometry degrades rapidly as mass is increased and is only ~10-5

Design of a Turn-Key 10 V Programmable Josephson Voltage Standard System

June 13, 2008
Author(s)
Paul D. Dresselhaus, Mike Elsbury, Charles J. Burroughs, David I. Olaya, Samuel P. Benz, Norman F. Bergren, Robert E. Schwall, Zoya Popovic
NIST is designing a 10 V Programmable Josephson Voltage Standard (PJVS) system with an improved microwave design and arrays of stacked NbXSi1-x-barrier Josephson junctions. For this new design a ?ground-up? approach, was used which takes into account all

An Optical System for Body Imaging from a Distance Using near-TeraHertz Frequencies

January 26, 2008
Author(s)
William Duncan, Robert E. Schwall, Kent D. Irwin, James A. Beall, Carl D. Reintsema, W.Bertrand (Randy) Doriese, Hsiao-Mei Cho, Brian Estey, Goutam Chattopadhyay, Peter Ade, Carole Tucker
We present the outline of the optical design of a TeraHertz (THz) imager for the detection of shrapnel-loaded improvised explosive devices (IED''s) at ''stand-off'' distances of 14 - 26 meters. The system will use 4 antenna-coupled TES detector arrays of

Quantum key distribution at 1550 nm with twin superconducting single-photon detectors

December 15, 2006
Author(s)
Robert Hadfield, Jonathan L. Habif, John Schlafer, Robert E. Schwall, Sae Woo Nam
The authors report on the full implementation of a superconducting detector technology in a fiber-based quantum key distribution (QKD) link. Nanowire-based superconducting single-photon detectors (SSPDs) offer single-photon detection with low dark counts

Quantum dot single photon sources studied with superconducting single photon detectors

November 1, 2006
Author(s)
Martin J. Stevens, Robert Hadfield, Robert E. Schwall, Sae Woo Nam, Richard P. Mirin
We report the observation of photon antibunching from a single, self-assembled InGaAs quantum dot (QD) at temperatures up to 135 K. The second-order intensity correlation, g(2)(0), is less than 0.260 ± 0.024 for temperatures up to 100 K. At 120 K, g(2)(0)

Single Photon Detector Comparison in a Quantum Key Distribution Link Testbed

October 25, 2006
Author(s)
Jonathan L. Habif, David S. Pearson, Robert Hadfield, Robert E. Schwall, Sae Woo Nam, Aaron J. Miller
We provide a direct comparison between the InGaAs avalanche photodiode (APD) and the NbN superconducting single photon detector (SSPD) for applications in fiber-based quantum cryptography. The quantum efficiency and dark count rate were measured for each

Time-correlated single-photon counting with superconducting single-photon detectors

October 1, 2006
Author(s)
Martin Stevens, Robert Hadfield, Robert E. Schwall, Sae Woo Nam, Richard Mirin
We report use of a niobium nitride superconducting single-photon detector in a time-correlated single-photon counting experiment. The detector has a timing jitter of 68 +/- 3 ps full-width at half-maximum with a Gaussian temporal profile. The detector's

Single photon source characterization with a superconducting single photon detector

December 26, 2005
Author(s)
Robert Hadfield, Martin Stevens, Stephen Gruber, Aaron J. Miller, Robert E. Schwall, Richard Mirin, Sae Woo Nam
Superconducting single photon detectors (SSPD) based on nanopatterned niobium nitride wires offer single photon counting at fast rates, low jitter, and low dark counts, from visible wavelengths well into the infrared. We demonstrate the first use of an