Princeton University

Medi-physics, Inc.

Nicholas N Kuzma

William Happer

Michael Romalis

Yuan-Yu Jau

Ian Nelson

Eli Miron

Amber B Post

The present invention provides a method and apparatus for increasing the intensity of coherent population trapping (CPT) resonances, used in atomic clocks and magnetometers, by pumping the atoms with light of alternating polarization. Pumping with such light, characterized by a photon spin vector that alternates in direction at a hyperfine frequency of the atoms at the location of the atoms, is referred to as push-pull pumping. In one embodiment of the system of the present invention, alkali-metal vapor is pumped with alternating circular-polarization Dlaser light that is intensity modulated at appropriate resonance frequencies, thereby exciting CPT resonances, which can be observed as increase in the mean transmittance of the alkali-metal vapor. These resonances are substantially enhanced due to an optically-induced concentration of atoms in the resonant energy sublevels.

Method and system for operating an atomic clock with alternating-polarization light

The present invention provides a method and system to simultaneously use the microwave and Zeeman end resonances associated with the same sublevel of maximum (or minimum) azimuthal quantum number m to lock both the atomic clock frequency and the magnetic field to definite values. This eliminates the concern about the field dependence of the end-resonance frequency. In an embodiment of the system of the present invention, alkali metal vapor is pumped with circularly-polarized Dlaser light that is intensity-modulated at appropriate resonance frequencies, thereby providing coherent population trapping (CPT) resonances. In another embodiment, pumping with constant-intensity circularly-polarized Dlaser light enhances magnetic resonances that are excited by alternating magnetic fields oscillating at appropriate resonance frequencies. In both embodiments, the resonances are greatly enhanced by concentrating most of the atoms in the initial state of the resonances, and by diminishing the spin-exchange broadening of the resonances. This leads to greater stability of optically pumped atomic clocks. This invention can also be used to operate an atomic magnetometer, where the feedback signal used to stabilize the magnetic field at the alkali-vapor cell can serve as a sensitive measure of the ambient magnetic field.

Method and system for operating an atomic clock with simultaneous locking of field and frequency

An apparatus and a method for providing a magnetic holding field about a chamber for accumulating frozen Xe. The apparatus includes a magnetic field source and a yoke for supporting the magnetic field source about the chamber. The magnetic field source provides a magnetic holding field having a field strength of greater than 2 kiloGauss. The apparatus may further include yoke for coupling the magnetic holding field through a portion of the chamber.

Magnetic holding field for cryogenically accumulated polarized 129Xenon

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Princeton, NJ, United States of America

Nicholas N Kuzma