University of New Hampshire

Xemed LLC

Other

F William Hersman

Jan Distelbrink

David W Watt

Mark Leuschner

Jeannette Carberry

Jan H Distelbrink

Hongguo Zhu

Iulian Constantin Ruset

A diode laser system employing a vapor cell in an external cavity and related techniques are disclosed. The system may be configured to provide high-power, multi-mode output within one or more narrow ranges of wavelengths. A beam emitted from the laser along an initial optical axis passes through a vapor cell, where the effective ground-state occupation density of the vapor is reduced, causing spatial gradients of the vapor's effective index of refraction. Refraction of rays passing through these gradients produces angular deflections, most significantly for rays where the gradients are strongest and for wavelengths whose index of refraction departs furthest from unity near these atomic transitions. An at least partially reflective surface which is not aligned with the initial optical axis but rather is aligned perpendicular to some of these deflected rays provides feedback within an angular range, thereby contributing to the gain of the laser source for these wavelengths.

System and techniques for diode laser wavelength spectrum narrowing

Gaseous laser systems and related techniques are disclosed. Techniques disclosed herein may be utilized, in accordance with some embodiments, in providing a gaseous laser system with a configuration that provides (A) pump illumination with distinct edge surfaces for an extended depth and (B) an output beam illumination from a resonator cavity with distinct edges in its reflectivity profile, thereby providing (C) pump beam and resonator beam illumination on a volume so that the distinct edge surfaces of its pump and resonator beam illumination are shared-edge surfaces with (D) further edge surfaces of the amplifier volume at the surfaces illuminated directly by the pump or resonator beams, as defined by optical windows and (optionally) by one or more flowing gas curtains depleted of the alkali vapor flowing along those optical windows. Techniques disclosed herein may be implemented, for example, in a diode-pumped alkali laser (DPAL) system, in accordance with some embodiments.

Gaseous laser systems with edge-defining element and related techniques

An apparatus, system, and methods for polarizing nuclei of a noble gas are disclosed. The disclosed system may include a polarization apparatus configured to polarize a noble gas mixture including xenon-129. The disclosed system also may include separate volumes for (1) saturating the polarizable noble gas mixture with alkali metal vapor, (2) desaturating said noble gas mixture from its alkali metal vapor after polarization is completed, (3) intermediate storage of the resultant polarized noble gas mixture, and (4) transfer of said polarized noble gas mixture to a storage vessel (e.g., a delivery bag). The disclosed system further may include separate reservoirs for (1) the noble gas(es) to be polarized, (2) lightweight gas(es) to displace the noble gas(es), and (3) a heavy inert gas (e.g., such as natural xenon) to push the polarized noble gas(es) into a storage vessel.

Apparatus, system, and methods for high-power polarization of noble gas nuclei

Gaseous laser systems and related techniques are disclosed. Techniques disclosed herein may be utilized, in accordance with some embodiments, in providing a gaseous laser system with a configuration that provides (A) pump illumination with distinct edge surfaces for an extended depth and (B) an output beam illumination from a resonator cavity with distinct edges in its reflectivity profile, thereby providing (C) pump beam and output beam illumination on a volume so that the distinct edge surfaces of its pump and beam illumination are shared-edge surfaces with (D) further edge surfaces of the amplifier volume at the surfaces illuminated directly by the pump or output beams, as defined by optical windows and (optionally) by one or more flowing gas curtains depleted of the alkali vapor flowing along those optical windows. Techniques disclosed herein may be implemented, for example, in a diode-pumped alkali laser (DPAL) system, in accordance with some embodiments.

The system and method for modifying the output beam parameters of a plurality of laser diode array sources comprises scalable pump sources for use with diode pumped alkali lasers. The present invention optimizes a diode laser pump source by spectrally-narrowing stacks of diode laser array bars using a single external cavity outfitted with a proprietary step-mirror and cylindrical optical elements. The system and method of the present invention multiplies by one-hundred fold the number of stacks that can be narrowed, vastly increasing the attainable power output by utilizing beam-splitters.

Scalable diode laser source for optical pumping

Techniques and architecture are disclosed for managing alkali vapor concentration in a lasing gas at non-condensing levels. In some instances, the disclosed techniques/architecture can be used to control and/or stabilize the concentration of alkali vapor in a lasing gas volume to any desired fraction of its saturation value under dynamically changing thermal loads. In some such instances, the concentration of alkali vapor in a given lasing gas volume can be maintained at a value which is sufficiently far from the saturation point to prevent or otherwise reduce condensation of the alkali vapor, for example, upon accelerating the lasing gas through a pressure drop into an optical pumping cavity of an alkali vapor laser system (e.g., such as a diode-pumped alkali laser, or DPAL, system). In some instances, the disclosed techniques/architecture can be used to establish a temperature gradient and/or an alkali vapor concentration gradient in the flowing lasing gas volume.

Techniques and apparatus for managing lasing gas concentrations

Techniques and architecture are disclosed for preserving optical surfaces (e.g., windows, coatings, etc.) in a flowing gas amplifier laser system, such as a diode-pumped alkali laser (DPAL) system. In some instances, the disclosed techniques/architecture can be used, for example, to protect optical surfaces in a DPAL system from: (1) chemical attack by pump-bleached alkali vapor atoms and/or ions; and/or (2) fouling by adherence thereto of reaction products/soot produced in the DPAL. Also, in some instances, the disclosed techniques/architecture can be used to substantially match the geometry of the pumping volume with that of the lasing volume, thereby minimizing or otherwise reducing the effects of amplified spontaneous emission (ASE) on DPAL output power. Furthermore, in some cases, the disclosed techniques/architecture can be used to provide a DPAL system capable of producing a beam output power in the range of about 20 kW to 10 MW, or greater.

Optical surface preservation techniques and apparatus

A polarizing apparatus has a thermally conductive partitioning system in a polarizing cell. In the polarizing region, this thermally conductive partitioning system serves to prevent the elevation of the temperature of the polarizing cell where laser light is maximally absorbed to perform the polarizing process. By employing this partitioning system, increases in laser power of factors of ten or more can be beneficially utilized to polarize xenon. Accordingly, the polarizing apparatus and the method of polarizingXe achieves higher rates of production.

Thermal management technology for polarizing xenon

Thermal management technology for polarizing Xenon

A system to increase the brightness of, and control gaps in, the light from an external cavity, spectrally narrowed, stack of diode laser bars employing a stepped mirror and transparent plates in the external cavity.

Spectral-narrowing diode laser array system

The present invention is a polarizing process involving a number of steps. The first step requires moving a flowing mixture of gas, the gas at least containing a polarizable nuclear species and vapor of at least one alkali metal, with a transport velocity that is not negligible when compared with the natural velocity of diffusive transport. The second step is propagating laser light in a direction, preferably at least partially through a polarizing cell. The next step is directing the flowing gas along a direction generally opposite to the direction of laser light propagation. The next step is containing the flowing gas mixture in the polarizing cell. The final step is immersing the polarizing cell in a magnetic field. These steps can be initiated in any order, although the flowing gas, the propagating laser and the magnetic field immersion must be concurrently active for polarization to occur.

Apparatus and method for polarizing polarizable nuclear species

A method and apparatus for the accumulation of hyperpolarizedXe is described. A gas mixture comprisingXe is flowed through a heat exchanger tube from the first end to the second end. Concurrently, the outer surface of the heat exchanger tube is controllably refrigerated, beginning with the second end, to a temperature low enough to freeze theXe on the inner surface of the heat exchanger tube.

Method and apparatus for accumulating hyperpolarized xenon

The present invention is a polarizing process involving a number of steps. The first step requires moving a flowing mixture of gas, the gas at least containing a polarizable nuclear species and vapor of at least one alkali metal, with a transport velocity that is not negligible when compared with the natural velocity of diffusive transport. The second step is propagating laser light in a direction, preferably at least partially through a polarizing cell. The next step is directing the flowing gas along a direction generally opposite to the direction of laser light propagating. The next step is containing the flowing gas mixture in the polarizing cell. The final step is immersing the polarizing cell in a magnetic field. These steps can be initiated in any order, although the flowing gas, the propagating laser and the magnetic field immersion must be concurrently active for polarization to occur.

Growing community of inventors

Durham, NH, United States of America

F William Hersman