Princeton University

Yuan-Yu Jau

William Happer

Fei Gong

Kiyoshi Ishikawa

Michael Romalis

Eli Miron

Nicholas N Kuzma

Brian Patton

Amber B Post

Katharine Estelle Jensen

Bart H McGuyer

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 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 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.

Growing community of inventors

Princeton, NJ, United States of America

Yuan-Yu Jau