Polarized Xenon Production: Powerful Narrowed Laser

描述（由申请人提供）：超极化氙和氦均已证明可用于肺部成像和肺部疾病定量。然而，与氦相反，超极化氙在液体和组织中具有高溶解度和特征化学位移，在溶解相成像中揭示了其微观环境。研究人体溶解相成像的成像协议可以有利地利用几次屏气，每次大约一升高度极化的气体。 UNH小组开发了一种新型的氙偏振器，该偏振器使气体混合物以相对较高的速度和较低的压力沿着与激光束相反的方向流动，在小批量生产时产生超过50%的偏振，在生产率超过每小时4升时产生20%的偏振。该偏振器的品质因数（偏振乘以生产率）目前超过所有其他偏振器技术一个数量级。 500埃的工作压力代表了更高的激光吸收（在更高的压力下）和更快的自旋交换速率（在更低的压力下）之间的折衷。我们的数值模拟表明，输出磁化与吸收的激光功率，即在光谱吸收带附近的一个狭窄的范围内的功率的比例。我们的研究小组最近委托了一台115 W的激光器，其光谱线宽缩小了0.5nm，是世界上最亮的794.7nm激光器。 我们请求STTR资助进一步开发和商业化高功率光谱窄激光器，用于超极化气体的自旋交换光泵浦。对于第一阶段，我们打算将这种光谱变窄的激光技术扩大到400 W以上，将其安装在适当适配的氙偏振器上，并确认磁化输出增加至少4倍。对于第二阶段，我们将通过对腔体的理论和实验优化来提高效率并减小尺寸;表征单个组件和整个激光器的性能;与供应商开发供应渠道;设计机械稳定性和可调节性;确定操作限制;并记录安全性。然后，我们可以商业化地提供从100 W到可能高达800 W的窄激光器，用于氦和氙的自旋交换偏振。

DESCRIPTION (provided by applicant): Both hyperpolarized xenon and helium have demonstrated utility in lung imaging and quantifying lung disease. In contrast to helium, however, hyperpolarized xenon has a high solubility in fluids and tissues and a characteristic chemical shift, revealing its microscopic environment in dissolved-phase imaging. An imaging protocol to investigate dissolved-phase imaging in humans could beneficially utilize several breath holds of roughly one liter each of highly polarized gas. The UNH group has developed a new type of xenon polarizer that flows the gas mixture at relatively high velocity and low pressure along a direction opposite to the laser beam, producing polarization of over 50% for small quantities and 20% for a production rate of over four liters per hour. The figure-of-merit (polarization times production rate) of this polarizer presently exceeds all other polarizer technologies by an order of magnitude. The 500 torr operating pressure represents a compromise between higher laser absorption (at higer pressure) and faster spin-exchange rates (at lower pressure). Our numerical simulations indicate that output magnetization scales with absorbed laser power, that is, power within a narrow range around the spectral absorption band. Our research group recently commissioned a 115W laser with narrowed O.Snm spectral linewidth, the world's brightest laser at 794.7nm. We request STTR funding to further develop and commercialize high-power spectrally narrowed lasers for spin-exchange optical pumping of hyperpolarized gas. For Phase I we intend to scale up this spectrally narrowed laser technology to over 400W, install it on a suitably adapted xenon polarizer, and confirm that magnetization output is increased at least 4-fold. For Phase II we will increase efficiency and decrease size by theoretical and experimental optimization of the cavity; characterize the performance of individual components and the full laser; develop supply channels with vendors; engineer mechanical stability and adjustability; determine operational limits; and document safety. We can then commercially offer narrowed lasers from 100W to perhaps as high as 800W for spin-exchange polarization of both helium and xenon.