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Search Publications by: Daniel Barker (Fed)

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Displaying 1 - 25 of 35

Effect of ''glancing'' collisions in the cold atom vacuum standard

February 12, 2025
Author(s)
Stephen Eckel, Daniel Barker, James A. Fedchak, Jacek Klos, Julia Scherschligt, Eite Tiesinga
We theoretically investigate the effect of "glancing" collisions on the ultra-high-vacuum pressure readings of the cold-atom vacuum standard (CAVS), based on either ultracold $^7$Li or $^87}$Rb atoms. Here, glancing collisions are those collisions between

Collision-resolved pressure sensing

April 11, 2024
Author(s)
Daniel Carney, Daniel Barker, Thomas W. LeBrun, David Moore, Jacob Taylor
Heat and pressure are ultimately transmitted via quantized degrees of freedom, like gas particles and phonons. While a continuous Brownian description of these noise sources is adequate to model measurements with relatively long integration times

Grating magneto-optical traps with complicated level structures

October 25, 2023
Author(s)
Daniel Barker, Peter Elgee, Ananya Sitaram, Eric Norrgard, Nikolai Klimov, Gretchen K. Campbell, Stephen Eckel
We study the forces and optical pumping within grating magneto-optical traps (MOTs) operating on transitions with non-trivial level structure. In contrast to the standard six-beam MOT configuration, rate equation modelling predicts that the asymmetric

Simulations of a frequency-chirped magneto-optical trap of MgF

September 8, 2023
Author(s)
Kayla Rodriguez, Nickolas Pilgram, Daniel Barker, Stephen Eckel, Eric Norrgard
We simulate the capture process of MgF molecules into a frequency-chirped molecular MOT. Our calculations show that by chirping the frequency, the MOT capture velocity is increased by about of factor of 4 to 80m/s, allowing for direct loading from a two

Accurate measurement of the loss rate of cold atoms due to background gas collisions for the quantum-based cold atom vacuum standard

August 1, 2023
Author(s)
Daniel Barker, James A. Fedchak, Jacek Klos, Julia Scherschligt, Abrar Sheikh, Eite Tiesinga, Stephen Eckel
We present measurements of thermalized collisional rate coefficients for ultra-cold $^7$Li and $^87}$Rb colliding with room-temperature He, Ne, N$_2$, Ar, Kr, and Xe. In our experiments, a combined flowmeter and dynamic expansion system, a vacuum metrology

Precise Quantum Measurement of Vacuum with Cold Atoms

December 20, 2022
Author(s)
Daniel Barker, Bishnu Acharya, James A. Fedchak, Nikolai Klimov, Eric Norrgard, Julia Scherschligt, Eite Tiesinga, Stephen Eckel
We describe the cold-atom vacuum standards (CAVS) under development at the National Institute of Standards and Technology. The CAVS measures pressure in the ultra-high and extreme-high vacuum regimes by measuring the loss rate of sub-millikelvin sensor

A constant pressure flowmeter for the extremely high vacuum

August 9, 2022
Author(s)
Stephen Eckel, Daniel Barker, James A. Fedchak, Emmanuel Newsome, Julia Scherschligt, Robert E. Vest
We demonstrate operation of a constant-pressure flowmeter capable of generating and accurately measuring flows as low as $1\times10^-13}$mol/s. Generation of such small flows is accomplished by using a small conductance element with $C\approx 25$nL/s

Comparison of two multiplexed portable cold atom vacuum standards

July 15, 2022
Author(s)
Lucas Ehinger, Bishnu Acharya, Daniel Barker, James A. Fedchak, Julia Scherschligt, Eite Tiesinga, Stephen Eckel
We compare the vacuum measured by two portable cold atom vacuum standards (pCAVS) based on ultracold $^7$Li atoms. Our pCAVS devices share the same laser system and measure the vacuum concurrently. The two pCAVS together detected a leak with a rate on the

Laser Spectroscopy of the y7PJo states of Cr I

March 16, 2022
Author(s)
Eric Norrgard, Daniel Barker, Stephen Eckel, Sergey Porsev, Charles Cheung, Mikhail Kozlov, Ilya Tupitsyn, Marianna Safronova
Here we report measured and calculated values of decay rates of the 3d$^4$($^5$D)4s4p($^3$P$^\rmo}}$)\ y$^7$P$^\rmo}}_2,3,4}$ states of Cr I. The decay rates are measured using time-correlated single photon counting with roughly 1\,\% total uncertainty. In

Lambda-enhanced gray molasses in a tetrahedral laser beam geometry

March 14, 2022
Author(s)
Daniel Barker, Eric Norrgard, Nikolai Klimov, James A. Fedchak, Julia Scherschligt, Stephen Eckel
We report observation of sub-Doppler cooling of lithium using an irregular-tetrahedral laser beam arrangement, which is produced by a nanofabricated diffraction grating. We are able to capture 11(2) % of the lithium atoms from a grating magneto-optical

Erratum: Collisions of room temperature helium with ultra-cold lithium and the van-der-Waals bound state of HeLi [Phys. Rev. A 101, 012702 (2020)]

February 28, 2022
Author(s)
Constantinos Makrides, Daniel Barker, James A. Fedchak, Julia Scherschligt, Stephen Eckel, Eite Tiesinga
We have found an error in the computation of the thermally-averaged total elastic rate coefficient for the collision of a room-temperature helium atom with an ultra-cold lithium atom presented. We omitted the factor $2/\sqrt\pi}$ in the normalization over

Progress towards comparison of quantum and classical vacuum standards

September 22, 2021
Author(s)
Daniel Barker, Nikolai Klimov, Eite Tiesinga, James A. Fedchak, Julia Scherschligt, Stephen Eckel
We present our progress towards a comparison of NIST's cold atom primary vacuum standard and a dynamic expansion vacuum standard. The cold atom vacuum standard (CAVS) converts the loss rate of atoms from a magnetic trap to a vacuum pressure using ab initio

Quantum-Based Photonic Sensors for Pressure, Vacuum, and Temperature Measurements: A Vison of the Future with NIST on a Chip

September 17, 2021
Author(s)
Jay H. Hendricks, Zeeshan Ahmed, Daniel Barker, Kevin O. Douglass, Stephen Eckel, James A. Fedchak, Nikolai Klimov, Jacob Edmond Ricker, Julia Scherschligt
The NIST on a Chip (NOAC) program's central idea is the idea that measurement technology can be developed to enable metrology to be performed "outside the National Metrology Institute" by the crea-tion of deployed and often miniaturized standards. These

PyLCP: A python package for computing laser cooling physics

September 9, 2021
Author(s)
Stephen Eckel, Daniel Barker, Eric Norrgard, Julia Scherschligt
We present a python object-oriented computer program for simulating various aspects of laser cooling physics. Our software is designed to be both easy to use and adaptable, allowing the user to specify the level structure, magnetic field profile, or the

NIST on a Chip: Photonic and Quantum-Based Sensors for Measurements of Pressure, Vacuum, Temperature and Beyond!

April 29, 2021
Author(s)
Jay H. Hendricks, Zeeshan Ahmed, Daniel Barker, Stephen Eckel, James A. Fedchak, Nikolai Klimov, Julia Scherschligt
At the core of the NIST on a Chip (NoAC) program is the idea that measurement technology can be developed to enable metrology to be done "outside the National Metrology Institute" by virtue of deployed and often miniaturized standards (that can also serve

Outgassing rate comparison of seven geometrically similar vacuum chambers of different materials and heat treatments

April 23, 2021
Author(s)
James A. Fedchak, Julia Scherschligt, Sefer Avdiaj, Daniel Barker, Stephen Eckel, Ben Bowers, Scott O'Connell, Perry Henderson
We have measured the water and hydrogen outgassing rates of seven vacuum chambers of identical geometry but constructed of different materials and heat treatments. Chambers of five different materials were tested: 304L, 316L, and 316LN stainless steels

Note: A Bitter-type electromagnet for complex atomic trapping and manipulation

February 12, 2021
Author(s)
Jacob L. Siegel, Daniel Barker, James A. Fedchak, Julia Scherschligt, Stephen Eckel
We create a pair of symmetric Bitter-type electromagnet assemblies capable of producing multiple field configurations including uniform magnetic fields, spherical quadruple traps, or Ioffe-Pritchard magnetic bottles. Unlike other designs, our coil allows

Magneto-optical trapping using planar optics

January 29, 2021
Author(s)
William McGehee, Wenqi Zhu, Daniel Barker, Daron Westly, Alexander Yulaev, Nikolai Klimov, Amit Agrawal, Stephen Eckel, Vladimir Aksyuk, Jabez J. McClelland
Laser-cooled atoms are a key component of many calibration-free measurement platforms— including clocks, gyroscopes, and gravimeters—and are a promising technology for quantum networking and quantum computing. The optics and vacuum hardware required to

Note: A Radio Frequency Voltage-Controlled Current Source for Quantum Spin Manipulation

October 19, 2020
Author(s)
Daniel S. Barker, Alessandro Restelli, James A. Fedchak, Julia K. Scherschligt, Stephen P. Eckel
We present a design for a wide-bandwidth, voltage-controlled current source that is easily integrated with radiofrequency magnetic field coils. Our design uses current feedback to compensate for the frequency-dependent impedance of a radiofrequency antenna

Confinement of an alkaline-earth element in a grating magneto-optical trap

October 15, 2020
Author(s)
Ananya Sitaram, Peter Elgee, Gretchen K. Campbell, Daniel Barker, Nikolai Klimov, Stephen Eckel
We demonstrate a compact magneto-optical trap (MOT) of alkaline-earth atoms using a nanofabricated diffraction grating chip. A single input laser beam, resonant with the broad 1S0 to 1P1 transition of strontium, forms the MOT in combination with three

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