Possible Condensation Laser

可能的凝聚激光

• 批准号: 8819659
• 负责人: John Fenn
• 金额: $ 3万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-09-01 至 1990-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8819659&HistoricalAwards=false
• 关键词: Possible; Condensation; Laser

1. Summary of Proposed Research: Experiments to be carried out will consist in exposing various gas mixtures to a corona discharge in a source chamber and then expanding the excited gas through a small nozzle into vacuum as a supersonic jet. Of particular interest are species whose excited states radiate in the infrared such as CO and CO2. Their radiation from the jet will be analyzed by Fourier Transform Infrared Spectrometry as well as by total radiation detectors. In some preliminary experiments the intensity of the radiation showed as much as a fivefold increase when the initial temperature and pressure of the source gas were such that condensation would be expected during the free jet expansion. The question thus arises as to whether this observed "superradiance" was due to a population inversion caused by clustering of the ground state molecules which would shift their absorption wavelength so that they could not absorb photons radiated by excited monomers. The objective of the research is to determine with what species and under what conditions the superradiance can be made to occur, the nature of the underlying mechanism, and whether that mechanism offers an effective new approach to useful lasers in the infrared regime. 2. Novelty: The sine qua non of laser operation is a population inversion in which the number density of molecules in an upper excited state exceeds the number density in the lower state produced when the excited molecule radiates a photon. Many kinds of processes have been used to populate an upper state in a laser system and/or to depopulate the corresponding lower state. To our knowledge inversions have not previously been achieved by the use of condensation to depopulate the lower state. In principle it should work and preliminary experiments with supersonic free jets indicate that it can occur in rapid adiabatic expansion of a gas containing vibrationally excited species. 3. Technological Impact: Preliminary experiments have shown remarkable superradiance from free jets containing vibrationally excited CO and CO2. The tentative explanation is a population inversion due to clustering or condensation of molecules in the lower state. If this conclusion is confirmed by the proposed research, the way would seem open for the development of new "condensation laser" systems. Because this approach should be applicable to almost any gaseous species that is infrared-active, there looms the prospect of a wide range of laser systems covering a large part of the infrared spectrum. Relatively complex molecules should offer tunability. Quantum efficiencies should be high because the lower state must have little or no remaining internal energy in order to condense.

1. 拟议研究摘要：拟进行的实验将 在于将各种气体混合物暴露于电晕放电， 源室，然后通过一个小的 喷嘴进入真空作为超音速射流。 特别感兴趣的是 其激发态辐射红外线的物质，如CO和 二氧化碳。 它们从喷流中发出的辐射将用傅立叶分析 变换红外光谱法和总辐射法 探测器 在一些初步实验中， 辐射显示，当最初的 源气体的温度和压力使得冷凝 在自由射流膨胀过程中会出现。 因此，问题 出现了关于是否这种观察到的"超辐射"是由于一个 基态成簇引起的布居数反转 这些分子会改变它们的吸收波长， 不能吸收被激发的单体辐射的光子。 客观 这项研究的目的是确定用什么样的物种和在什么样的环境下， 条件的超辐射可以发生，性质的 基础机制，以及该机制是否提供了有效的 在红外区的有用激光的新方法。 2. 新奇：激光手术的必要条件是人口 反演中的分子数密度在一个上层 激发态超过较低态的数密度 当受激分子辐射光子时产生。 我们的产品种类繁多 的过程已经被用来填充激光器中的上态 系统和/或减少相应的较低状态。 到 我们的知识反演以前没有实现的 使用冷凝来减少较低状态的人口。 原则上 它应该工作和初步实验与超音速自由 射流表明，它可以发生在快速绝热膨胀的一个 含有振动激发物质的气体。 3. 技术影响：初步实验表明 从包含振动的自由喷流中产生的显著超辐射 激发CO和CO2。 初步的解释是， 反转由于分子的聚集或凝聚， 下州。 如果这一结论得到拟议中的 研究，新的发展道路似乎是开放的。 "冷凝激光"系统。 因为这种方法应该是 适用于几乎任何红外活性的气体物质， 出现了一个广泛的激光系统的前景 覆盖了红外光谱的大部分。 相对 复杂分子应该提供可调性。 量子效率 应该是高的，因为较低的状态必须很少或没有 为了凝聚体内的能量