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Search Publications by: John Kitching (Fed)

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Displaying 51 - 75 of 225

Frequency shift mitigation in a cold-atom CPT clock

May 8, 2016
Author(s)
Xiaochi Liu, John Kitching, Elizabeth Donley, Eugene N. Ivanov
An upgrade in the laser interrogation system for our cold-atom clock based on coherent population trapping has resulted in a reduced light shift. The new approach makes use of an electro-optic modulator to significantly reduce the phase coherence of the

Extended Source Interferometry in the Compact Regime

April 4, 2016
Author(s)
Bruno M. Pelle, Gregory W. Hoth, Stefan Riedl, John E. Kitching, Elizabeth A. Donley
We present an atom interferometer based on an expanding cloud of laser-cooled atoms sensitive to rotations along two axes and acceleration along one axis in an effective volume of 1 cm3. We observed spatially resolved fringes by imaging the expanding cloud

NIST on a Chip: Realizing SI units with microfabricated alkali vapour cells

October 16, 2015
Author(s)
John E. Kitching, Elizabeth A. Donley, Svenja A. Knappe, Matthew T. Hummon, Argyrios Dellis, Jeffrey A. Sherman, Kartik A. Srinivasan, Vladimir A. Aksyuk, Qiliang Li, Daron A. Westly, Brian J. Roxworthy, Amit Lal
We describe several ways in which microfabricated alkali atom vapour cells might potentially be used to accurately realize a variety of SI units, including the second, the meter, the kelvin, the ampere and the volt, in a compact, low-cost “chip-scale”

Compact atom-interferometer gyroscope based on an expanding ball of atoms

October 12, 2015
Author(s)
Elizabeth A. Donley, John E. Kitching, Stefan Riedl, Gregory W. Hoth, Bruno M. Pelle
We present a compact atom interferometer based on 87Rb atoms that can simultaneously measure rotations and accelerations with a single source of atoms in a 300 cm3 vacuum package.

Microfabricated Optically-Pumped Magnetometers for Biomagnetic Applications

October 12, 2015
Author(s)
Svenja A. Knappe, John E. Kitching, Orang Alem, Dong Sheng
We report on the progress in developing microfabricated optically-pumped magnetometer arrays for imaging applications. We have improved our sensitivities by several orders of magnitude in the last ten years, Now, our zero-field sensors reach values below

Resonant interaction of trapped cold atoms with a magnetic cantilever tip

June 26, 2015
Author(s)
John E. Kitching, Chris Montoya, Jose Valencia, Andrew A. Geraci, Matt Eardley, John M. Moreland
Magnetic resonance in an ensemble of laser-cooled trapped Rb atoms is excited using a micro cantilever with a magnetic tip. The cantilever is mounted on a multi-layer atom chip designed to capture, cool, and magnetically transport cold atoms. The coupling

Fetal magnetocardiography measurements with a multichannel microfabricated atomic magnetometer array

June 3, 2015
Author(s)
Svenja A. Knappe, Orang Alem, Tilmann H. Sander, Rahul R. Mhaskar, John LeBlanc, Hari Eswaran, Uwe Steinhoff, Yoshio Okada, John E. Kitching, Lutz Trahms
Following the rapid progress in the development of atomic magnetometer technology for the measurement of magnetic fields in the femtotesla range, a successful assembly of individual sensors into an array of nearly identical sensors is within reach. The

Light shifts in a pulsed cold-atom coherent-population-trapping clock

April 10, 2015
Author(s)
Eric M. Blanshan, Elizabeth A. Donley, John E. Kitching
Field-grade atomic clocks capable of primary standard performance in compact physics packages would be of significant value in a variety of applications. A cold-atom coherent population trapping clock featuring laser-cooled 87Rb atoms and pulsed Ramsey

Magnetoencephalography of Epilepsy with a Microfabricated Atomic Magnetrode

October 22, 2014
Author(s)
Svenja A. Knappe, Orang Alem, Alex M. Benison, Daniel S. Barth, John E. Kitching
We measured the magnetic signature of epileptiform discharges with high signal-to-noise ratio, using microfabricated atomic magnetometers based on laser spectroscopy of rubidium vapor and similar in size to scalp EEG electrodes. Sensitivity to neuronal

Ultra-Low-Field NMR Relaxation and Diffusion Measurements Using an Optical Magnetometer

July 31, 2014
Author(s)
John E. Kitching, P. Ganssle, H Shin, Scott J. Seltzer, Vikram S. Bajaj, Micah P. Ledbetter, Dimitry Budkerl, Svenja A. Knappe, A Pines
In this work, we have demonstrated for the first time that an alkali vapor cell magnetometer has sufficient sensitivity to chemically resolve a heterogeneous mixture of oil and water by its relaxation and diffusion properties, both in one dimensional

Frequency Biases in a Cold-Atom Coherent Population Trapping Clock

May 22, 2014
Author(s)
Elizabeth A. Donley, Eric M. Blanshan, Francois-Xavier R. Esnault, John E. Kitching
A compact cold-atom clock based on coherent population trapping (CPT) has been developed. The clock typically demonstrates a short-term fractional frequency stability of 4x10 -11/√τ limited by frequency noise on the interrogation lasers. The largest two

Optical hyperpolarization and NMR detection of 129 Xe on a microfluidic chip

May 20, 2014
Author(s)
Ricardo Jimenez Martinez, Daniel J. Kennedy, Michael Rosenbluh, Elizabeth A. Donley, Svenja A. Knappe, Scott J. Seltzer, Hattie L. Ring, Vikram S. Bajaj, John E. Kitching
We present a microfluidic chip that enables the production of laser-polarized 129Xe gas and its optical detection. Production of polarized 129Xe and its remote detection is achieved under flowing gas conditions at low magnetic fields in two separate

Cold-atom double-lambda coherent population trapping clock

October 31, 2013
Author(s)
Elizabeth A. Donley, Francois-Xavier R. Esnault, Eric M. Blanshan, Eugene N. Ivanov, Robert E. Scholten, John E. Kitching
Miniature atomic clocks based on coherent population trapping (CPT) states in thermal atoms are emerging as an important component in many field applications, particularly where satellite frequency standards are not accessible. Cold-atom CPT clocks promise

Cancellation of Doppler Shifts in a Cold-Atom CPT Clock

July 25, 2013
Author(s)
Elizabeth A. Donley, Francois-Xavier R. Esnault, Eric M. Blanshan, John E. Kitching
A compact cold-atom clock based on coherent population trapping (CPT) is being developed. Long-term goals for the clock include achieving a fractional frequency accuracy of 1x10 -13 in a package of less than 10 cm 3 in volume. Here we present an overview

Microfabricated Atomic Magnetometers

April 15, 2013
Author(s)
Svenja A. Knappe, John E. Kitching
In this chapter, we discuss miniaturized atomic magnetometers, and the technology and applications relevant to this somewhat unusual direction in magnetometer research and development. By “miniaturized”, we mean, in addition to their size, magnetometers

Nuclear magnetic resonance gyroscopes

April 15, 2013
Author(s)
Elizabeth A. Donley, John E. Kitching
This review begins with an introduction to NMR gyroscopes (NMRGs), followed by a discussion of the frequency shifts and relaxation mechanisms that determine and their performance. Specific NMRG implementations are then reviewed, including dual NMR species

Atom numbers in magneto-optic traps with millimeter scale laser beams

February 22, 2013
Author(s)
Gregory W. Hoth, Elizabeth A. Donley, John E. Kitching
We measure the number of atoms, N, that can be trapped in a conventional vapor cell MOT using beams that have a diameter d in the range 1-5 mm. We show that the N \propto d 3.6 scaling law observed for larger MOTs is a robust approximation for optimized

A Low-Power, High-Sensitivity Micromachined Optical Magnetometer

December 11, 2012
Author(s)
Rahul R. Mhaskar, Svenja A. Knappe, John E. Kitching
We demonstrate a fiber-optically coupled optical magnetometer based on a microfabricated 87Rb vapor cell in a micromachined silicon sensor head. The cell is optically heated with light at 1.5 mm brought to the cell through an optical fiber and absorbed by

High Bandwidth Optical Magnetometer

November 28, 2012
Author(s)
Ricardo Jimenez Martinez, William C. Griffith, Svenja A. Knappe, John E. Kitching, Mark Prouty
We demonstrate a scalar 87Rb optical magnetometer that retains magnetic eld sensitivities below 10 pT/√Hz over 3dB bandwidths of 10 kHz in an ambient eld Bo = 11.4 microT and using a measurement volume of 1 mm 3. The magnetometer operates at high atomic

A COLD-ATOM CLOCK BASED ON COHERENT POPULATION TRAPPING

November 26, 2012
Author(s)
Elizabeth A. Donley, Francois-Xavier R. Esnault, Eric M. Blanshan, John E. Kitching
A compact cold-atom clock based on coherent population trapping is being developed. The clock aims to ultimately achieve a timing uncertainty of a few nanoseconds per day. Here we present an initial evaluation of the three main systematic frequency shifts

A Compact Cold-Atom Frequency Standard Based on Coherent Population Trapping

May 24, 2012
Author(s)
Francois-Xavier R. Esnault, John Kitching, Elizabeth Donley
We present the status of our cold-atom clock based on coherent population trapping, including the present clock stability and a preliminary evaluation of the three main systematic frequency shifts: the 1st-order Doppler shift, the Zeeman shift, and the

Magnetoencephalography with a chip-scale atomic magnetometer

April 17, 2012
Author(s)
Svenja A. Knappe, Tillman H. Sander, Jan Preusser, Rahul R. Mhaskar, John E. Kitching, Lutz Trahms
We report on the measurement of somatosensory-evoked and spontaneous magnetoencephalography signals with a chip-scale atomic magnetometer. This uncooled, fiber-coupled sensor has a sensitive volume of 0.58 mm 3 inside a sensor head of volume 1 cm 3. When

Atom-number amplification in a magneto-optical trap via stimulated light forces

January 10, 2012
Author(s)
Elizabeth A. Donley, Tara C. Liebisch, Eric M. Blanshan, John E. Kitching
We have decelerated an atomic beam of 87 Rb using a stimulated-emission slowing technique that makes use of a bichromatic standing light wave of high intensity and increased the load rate into a small magneto-optical trap by up to a factor of 20. We

Chip-scale room-temperature atomic magnetometers for biomedical measurements

September 14, 2011
Author(s)
Svenja A. Knappe, Rahul R. Mhaskar, Jan Preusser, John E. Kitching, Lutz Trahms, Tillman H. Sander
We describe a portable 4-channel array of chip-scale atomic magnetometers in a flexible flying-lead configuration. These microfabricated, uncooled sensors with volumes below 1 cm 3 demonstrate sensitivities around 100 fT/Hz 1/2 and bandwidths of several