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Search Publications by: Stephen Eckel (Fed)

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Displaying 26 - 45 of 45

Dual Cavity Refractivity measurements using a single Laser

September 15, 2019
Author(s)
Kevin O. Douglass, Jacob Edmond Ricker, Stephen Eckel, Jay H. Hendricks
We present a method for measuring refractivity-based pressure changes using a dual Fabry-Perot cavity utilizing a single laser with off-set sideband locking to the second cavity. Preliminary data illustrate the utility of the technique.

A wide-bandwidth, high-power radio-frequency driver for acousto-optic and electro-optic devices

August 6, 2019
Author(s)
Daniel S. Barker, Neal C. Pisenti, Alessandro Restelli, Julia K. Scherschligt, James A. Fedchak, Gretchen K. Campbell, Stephen P. Eckel
We present a design for a general-purpose radio-frequency amplifier circuit that is suitable for driving acousto-optic and electro-optic devices. Our design uses telecom amplifiers to achieve power output > 1 W over a 10 MHz to 1.1 GHz frequency range, and

Nuclear-Spin Dependent Parity Violation in Optically Trapped Polyatomic Molecules

July 3, 2019
Author(s)
Eric B. Norrgard, Daniel S. Barker, Stephen P. Eckel, James A. Fedchak, Nikolai N. Klimov, Julia K. Scherschligt
We investigate using optically trapped linear polyatomic molecules as probes of nuclear spin- dependent parity violation. The presence of closely spaced, opposite-parity $\ell$-doublets is a general feature of such molecules, allowing parity-violation

A single-beam slower and magneto-optical trap using a nanofabricated grating

June 11, 2019
Author(s)
Daniel S. Barker, Eric B. Norrgard, Nikolai N. Klimov, James A. Fedchak, Julia K. Scherschligt, Stephen P. Eckel
We demonstrate a compact (0.25 L) system for laser cooling and trapping atoms from a heated dispenser source. Our system uses a nano-fabricated diffraction grating to generate a magneto- optical trap (MOT) using a single input laser beam. An aperture in

Light-induced atomic desorption of lithium

October 8, 2018
Author(s)
Daniel S. Barker, Eric B. Norrgard, Julia K. Scherschligt, James A. Fedchak, Stephen P. Eckel
We demonstrate loading of a Li magneto-optical trap using light-induced atomic desorption. The magneto-optical trap confines up to approximately 10000 lithium atoms with loading rates up to 4000 atoms/s. We study the Li desorption rate as a function of the

Challenges to miniaturizing cold atom technology for deployable vacuum metrology

September 14, 2018
Author(s)
Stephen P. Eckel, Daniel S. Barker, James A. Fedchak, Nikolai N. Klimov, Eric B. Norrgard, Julia K. Scherschligt, Constantinos Makrides, Eite Tiesinga
Cold atoms are excellent metrological tools; they currently realize SI time and, soon, SI pressure in the ultra-high (UHV) and extreme high vacuum (XHV) regimes. The development of primary, vacuum metrology based on cold atoms currently falls under the

Quantum-based vacuum metrology at NIST

June 20, 2018
Author(s)
Julia K. Scherschligt, James A. Fedchak, Zeeshan Ahmed, Daniel S. Barker, Kevin O. Douglass, Stephen P. Eckel, Edward T. Hanson, Jay H. Hendricks, Thomas P. Purdy, Jacob E. Ricker, Robinjeet Singh
The measurement science in realizing and disseminating the SI unit for pressure, the pascal (Pa), has been the subject of much interest at NIST. Modern optical-based techniques for pascal metrology have been investigated, including multi-photon ionization

Recent Developments in Surface Science and Engineering, Thin Films, Nanoscience, Biomaterials, Plasma Science, and Vacuum Technology

May 31, 2018
Author(s)
Miran Mozetic, Alenka Vesel, Gregor Primc, J. Bauer, A. Eder, G. H. S. Schmid, David Ruzic, Zeeshan Ahmed, Daniel Barker, Kevin O. Douglass, Stephen Eckel, James A. Fedchak, Jay H. Hendricks, Nikolai Klimov, Jacob Edmond Ricker, Julia Scherschligt, Jack A. Stone Jr., Gregory F. Strouse, I. Capan, M Buljan, S. Milosevic, C Teichert, S R. Cohen, A G. Silva, M Lehocky, P Humpolicek, C Rodriguez, J Hernandez-Montelongo, E Punzon-Quijorna, D Mercier, M Manso-Silvan, G Ceccone, A Galtayries, K Stana-Kleinschek, I Petrov, J E. Greene, J Avila, C Y. Chen, B Caja, H Yi, A Boury, S Lorcy, M C. Asensio, T Gans, D O?Connell, F Reniers, A Vincze, M Anderle
Nanometer-sized structures, surfaces and sub-surface phenomena have played an enormous role in science and technological applications and represent a driving-force of current interdisciplinary science. Recent developments include the atomic-scale

A 3D-printed alkali metal dispenser

May 1, 2018
Author(s)
Eric B. Norrgard, Daniel S. Barker, James A. Fedchak, Nikolai N. Klimov, Julia K. Scherschligt, Stephen P. Eckel
We demonstrate and characterize a source of Li atoms made from direct metal laser sintered Ti. The source's outgassing rate is measured to be $5 \,(2)\cdot 10^{-7}$\,$\rm{Pa}~ \rm{L}~ \rm{s}^{-1}$ at the temperature which optimizes the number of atoms

A supersonically expanding Bose-Einstein condensate: an expanding universe in the lab

April 19, 2018
Author(s)
Stephen P. Eckel, Avinash Kumar, Theodore Jacobson, Ian B. Spielman, Gretchen K. Campbell
We study the dynamics of a supersonically expanding Bose-Einstein ring condensate both experimentally and theoretically using simulations. Such expansion shows a redshift of long-wavelength excitations, similar to those seen in the standard cosmological

Vacuum Furnace for Degassing Stainless-Steel Vacuum Components

March 1, 2018
Author(s)
James A. Fedchak, Julia K. Scherschligt, Daniel S. Barker, Stephen P. Eckel, Alex P. Farrell, Makfir Sefa
Ultra-high vacuum systems must often be constructed of materials with ultra-low outgassing rates to achieve pressure of 10-6 Pa and below. In such a case, any component placed into the ultra-high vacuum system must also be constructed of materials with

Development of a new UHV/XHV pressure standard (Cold Atom Vacuum Standard)

November 10, 2017
Author(s)
Julia Scherschligt, James A. Fedchak, Daniel Barker, Stephen Eckel, Nikolai Klimov, Constantinos Makrides, Eite Tiesinga
The National Institute of Standards and Technology has recently begun a program to develop a primary pressure standard that is based on ultra-cold atoms, covering a pressure range of 1 × 10-6 Pa to 1 × 10-10 Pa and possibly lower. These pressures

Perspectives for a new realization of the pascal by optical methods

October 24, 2017
Author(s)
Jay H. Hendricks, Karl Jousten, Jack A. Stone Jr., Patrick F. Egan, Tom Rubin, Christof Gaiser, Rene Schodel, James A. Fedchak, Jacob E. Ricker, Jens Fluegge, Stephen P. Eckel, Julia K. Scherschligt, Daniel S. Barker, Kevin O. Douglass, Gregory F. Strouse, Uwe Sterr, Waldimir Sabuga
Since the beginning of measurement of pressure in the 17th century, the unit of pressure has been defined by the relationship of force per unit area. The present state of optical technology now offers the possibility of using a thermodynamic definition

Contact resistance and phase slips in mesoscopic superfluid atom transport

June 15, 2016
Author(s)
Stephen Eckel, Jeffrey Lee, Fred Jendrejewski, Christopher Lobb, Gretchen K. Campbell, Wendell Hill
We have experimentally measured both resistive flow and superflow with bosonic atoms in a mesoscopic transport experiment. Our system, consisting of two Bose-Einstein condensates coupled by a narrow channel, shows resistive flow for currents above a

Minimally destructive, Doppler measurement of a quantized, superfluid flow

February 1, 2016
Author(s)
Avinash Kumar, Neil Anderson, William D. Phillips, Stephen P. Eckel, Gretchen K. Campbell, Sandro Stringari
The Doppler effect, the shift in the frequency of sound due to motion, is present in both classical gases and quantum superfluids. Here, we perform an in-situ, minimally destructive measurement, of the persistent current in a ring-shaped, superfluid Bose

Interferometric Measurement of the Current-Phase Relationship of a Superfluid Weak Link

September 22, 2014
Author(s)
Stephen Eckel, Fred Jendrzejewski, Avinash Kumar, Christopher J. Lobb, Gretchen K. Campbell
Weak connections between superconductors or superfluids differ from classical links due to quantum coherence, which allows flow without resistance. Transport properties through such weak links can be described with a single function, the current-phase

Resistive Flow in a Weakly Interacting Bose-Einstein condensate

July 25, 2014
Author(s)
Fred Jendrzejewski, Stephen P. Eckel, Noel Murray, Calib Lanier, Mark Edwards, Christopher J. Lobb, Gretchen K. Campbell
We report the direct observation of resistive flow through a weak link in a weakly interacting atomic Bose- Einstein condensate (BEC). Two weak links separate our ring-shaped superfluid atomtronic circuit into two distinct regions, a source and a drain

Hysteresis in Quantized Superfluid Atomtronic Circuit

February 14, 2014
Author(s)
Stephen P. Eckel, Jeffrey Lee, Fred Jendrzejewski, Noel Murray, Charles W. Clark, Christopher J. Lobb, William D. Phillips, Edwards Mark, Gretchen K. Campbell
Atomtronics is an emerging interdisciplinary field that seeks new functionality by creating devices and circuits where ultra-cold atoms play a role analogous to the electrons in electronics. Hysteresis in atomtronic circuits may prove to be a crucial