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Search Publications by: John Kitching (Fed)

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Displaying 101 - 125 of 431

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