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Search Publications by: John Kitching (Fed)

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Displaying 51 - 75 of 218

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

Atomic Sensors - A Review

September 1, 2011
Author(s)
John E. Kitching, Svenja A. Knappe, Elizabeth A. Donley
We discuss the basic physics and instrumentation issues related to high performance physical and inertial sensors based on atomic spectroscopy.

Note: Detection of a single cobalt microparticle with a microfabricated atomic magnetometer

August 23, 2011
Author(s)
Svenja A. Knappe, D. Maser, S. Pandey, H. Ring, Micah P. Ledbetter, John E. Kitching, Dimitry Budkerl
Detection of the magnetic signal of a single, 2 {um}m cobalt microparticle using an atomic magnetometer based on a microfabricated vapor cell is presented. These results represent an improvement by a factor of 10 in terms of the detected magnetic moment

MOT Loading Enhancement with Stimulated Light Forces

July 31, 2011
Author(s)
Elizabeth A. Donley, Tara C. Liebisch, Eric M. Blanshan, John E. Kitching
We demonstrate atom number enhancement in a magneto-optical trap (MOT) by use of bichromatic cooling to slow an atomic beam that is loaded into a MOT. Bichromatic cooling employs stimulated emission to apply strong cooling forces that are not limited by

Status of a compact cold-atom CPT frequency standard

July 31, 2011
Author(s)
Elizabeth A. Donley, Francois-Xavier R. Esnault, John E. Kitching, Eugene N. Ivanov
We describe the main progress towards the realization of a cold atom frequency standard based on coherent population trapping (CPT). We explain our particular CPT configuration and give details on the experimental setup.

Parahydrogen-enhanced zero-field nuclear magnetic resonance

May 1, 2011
Author(s)
Svenja A. Knappe, T. Theis, P. Ganssle, G Kervem, M Ledbetter, D Budker, A Pines, John E. Kitching
Nuclear magnetic resonance (NMR) is a powerful analytical tool for determination of molecular structure and function, with broad impact in biology, medicine, materials science, and fundamental research. Conventionally, NMR is performed in multiTesla

Femtotesla atomic magnetometry in a microfabricated vapor cell

December 20, 2010
Author(s)
William C. Griffith, Svenja A. Knappe, John Kitching
We describe an optically pumped 87Rb magnetometer with 4.5 fT/Hz 1/2 sensitivity when operated in the spin-exchange relaxation free (SERF) regime. The magnetometer uses a microfabricated vapor cell, consisting of a cavity etched in a 1 mm thick silicon