Princeton University

The State University of New York

Other

Medi-physics, Inc.

Sri International

William Happer

Gordon D Cates, Jr

Bastiaan Driehuys

Brian Saam

Yuan-Yu Jau

Mitchell S Albert

Dilip Balamore

Arnold Wishnia

Eli Miron

Kenton Christopher Hasson

Geri T K Zollinger

Daniel K Walter

Nicholas N Kuzma

Fei Gong

Kiyoshi Ishikawa

Ilhan A Aksay

Sterling Eduard McBride

Timothy James Davis

Michael Romalis

Alan Michael Braun

Daniel Martin Dabbs

Henry Y Tang

Katharine Estelle Jensen

Ming Feng Hsu

Bart H McGuyer

Mikhail V Romalis

Brian Patton

Amber B Post

Christopher J Erickson

Hunter Middleton

The present invention relates to a method and system for polarizing a solid compound of interest via spin transfer from an optically-pumped alkali vapor. In one embodiment, the method provides a cell which contains a solid compound as well as pure alkali metal and some amount of buffer gas. The cell is heated to vaporize some of the pure alkali. Resonant laser light is passed through the cell to polarize the atomic vapor, a process known as 'optical pumping.' Optical pumping can transfer order from photons to atoms, causing a buildup of vapor atoms in one angular momentum state. This vapor polarization is then transferred through the surface of the solid compound in order to polarize the nuclei in the bulk of the compound. This can produce nuclear polarizations in the sample many times larger than the limit set by thermal equilibrium. The method can be used in nuclear magnetic resonance (NMR) or magnetic resonance imaging (MRI).

Polarizing nuclei solids via spin transfer from an optically-pumped alkali vapor

A transport unit includes a plurality of permanent magnets arranged to provide a magnetic holding field for protecting hyperpolarized gas during storage and/or transport. The permanent magnets are configured in a relatively light weight manner to project a substantially cylindrical magnetic holding field or spherical holding field in space. The magnet arrangements can include primary magnets and field shaping secondary magnets which act to enlarge the region of homogeneity. The permanent magnet arrangement can also be provided with a cylindrical shaped flex sheet magnetically activated to provide the magnetic holding field. The permanent magnet arrangements do not require disassembly to insert or remove one or more containers of hyperpolarized gas in or out of the transport unit.

Hyperpolarized gas transport and storage devices and associated transport and storage methods using permanent magnets

A polarization gain medium such as an emitting laser diode provides the optical pumping. An atomic vapor cell is positioned in the laser cavity providing spontaneous push-pull optical pumping inside the laser cavity. This causes the laser beam to be modulated at hyperfine-resonance frequency. A clock signal is obtained from electrical modulation across the laser diode.

Method and system for operating an atomic clock using a self-modulated laser with electrical modulation

The present invention relates to a method and system for electrolytic fabrication of cells. A cell can be formed of a silicon layer (cathode) sandwiched between layers of glass. One or more holes are formed in the silicon layer. An alkali metal enriched glass material is placed in or associated with the one or more holes. Electrolysis is used to make the alkali metal ions in the alkali metal enriched glass material combine with electrons from the silicon cathode to form neutral alkali metal atoms in the one or more holes.

Method and system for electrolytic fabrication of atomic clock cells

The present invention provides a system and method for achieving a calibration-free primary atomic clock standard operating at the 0-0 transition free-atom frequency, thus creating a primary frequency standard, with attributes that include scalable to chip-scale dimensions and power consumption.

System and method for modulating pressure in an alkali-vapor cell

The present invention relates to a method and system to suppress or eliminate light shift in an optical pumping system, such as an atomic clock. The method uses modulation of a radiation source, such as a radio frequency or microwave source, to simultaneously lock the frequency of the radiation source to an atomic resonance and lock the frequency of the optical pumping source in order to suppress or eliminate light shift. In one embodiment, the method of the present invention directly utilizes the out-of-phase channel of a lock-in amplifier to additionally lock an optical pumping source to a zero-light-shift frequency, where the in-phase channel is used to lock the frequency of the radiation source to an atomic resonance.

Method for suppressing light shift in optical pumping systems

The present invention relates to a method and system in which multi-coherent resonances of a microwave in which the alkali-metal atoms in the ground state are driven simultaneously by a microwave hyperfine frequency &#x3a9;and a Zeeman frequency &#x3a9;. The driving influences on the atom can include magnetic fields or by optically pumping light modulated by a Zeeman frequency &#x3a9;or a microwave hyperfine frequency &#x3a9;or by combinations of their harmonics or subharmonics. Multi-coherent resonances permit simultaneous measurement or control of the ambient magnetic field and measurement or control of a hyperfine resonance frequency of alkali-metal atoms. In one embodiment, the hyperfine frequency for a controlled magnetic field can serve as an atomic clock frequency.

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

The present invention provides a method and apparatus for making atomic clocks or atomic magnetometers as self-modulated laser systems based on the physics of push-pull optical pumping. An atomic vapor cell is required to be in the laser cavity. With proper conditions, spontaneous push-pull optical pumping can occur inside the laser cavity. This causes the laser beam to be modulated at hyperfine-resonance frequency. With a fast photodetector, the modulated laser signal can be converted into the electrical signal, which serves as the atomic clock ticking signal or magnetometer signal. The self-modulated laser system does not use any local oscillator and the microwave circuit to lock the oscillator frequency to the hyperfine-resonance frequency, and therefore can consume less power and become more compact than conventional systems. This invention will benefit applications of time measurements and magnetic-field measurements.

Method and system for operating a laser self-modulated at alkali-metal atom hyperfine frequency

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 relates to a method and system for using end resonances of highly spin-polarized alkali metal vapors for an atomic clock, magnetometer or other system. A left end resonance involves a transition from the quantum state of minimum spin angular momentum along the direction of the magnetic field. A right end resonance involves a transition from the quantum state of maximum spin angular momentum along the direction of the magnetic field. For each quantum state of extreme spin there are two end resonances, a microwave resonance and a Zeeman resonance. The microwave resonance is especially useful for atomic clocks, but it can also be used in magnetometers. The low frequency Zeeman resonance is useful for magnetometers.

Method and system for operating an atomic clock with reduced spin-exchange broadening of atomic clock resonances

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

A method of imaging a spatial distribution of a noble gas by nuclear magnetic resonance spectrometry includes detecting a spatial distribution of at least one noble gas by NMR spectrometry and generating a representation of said spatial distribution of the noble gas. The noble gas is selected from noble gas isotopes having nuclear spin, preferably Xenon-129 and/or Helium-3. The noble gas is at least thermally or equilibrium polarized and is preferably hyperpolarized, most preferably hyperpolarized by optical (laser) pumping in the presence of an alkali metal or by metastability exchange. The generation of the representation of the noble gas spatial distribution includes at least one dimension, preferably 2 or 3 dimensions of the spatial distribution. The noble gas may be imaged according to the invention in chemical or biological systems, preferably in a human or animal subject or organ system or tissue thereof. Also, apparatus for nuclear magnetic resonance imaging of the spatial distribution of at least one noble gas includes means for imaging a noble gas by NMR spectrometry and means for providing and/or storing imageable quantities of a noble gas, preferably hyperpolarized Xenon-129 and/or Helium-3. Also, a medical composition includes a medically acceptable bifunctional gas effective for in vivo anesthesiological and NMR imaging functions, including at least one noble gas, preferably hyperpolarized Xenon-129 and/or Helium-3.

Magnetic resonance imaging using hyperpolarized noble gases

The present invention relates to a polarization cell which is coated with glass deposited from a sol-gel used for hyperpolarizing noble gases. The invention also includes a method for hyperpolarizing noble gases utilizing the polarization cell coated with glass deposited from a sol-gel. These polarization cells can also be incorporated into containers used for storage and transport of the hyperpolarized noble gases.

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Princeton, NJ, United States of America

William Happer