Study of elementary processes for the lower laser level of the copper vapor laser

铜蒸气激光器低激光能级基本工艺研究

基本信息

批准号：
05452196
负责人：
GOTO Toshio
金额：
$ 4.42万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05452196/
关键词：
Cu metastable atoms diffusion coefficient electron collisional de-excitation saturated absorption spectroscopy copper vapor laser laser absorption spectroscopy 銅原子拡散定数

项目摘要

In the powerful and highly efficient copper vapor laser, the lower levels of the laser transitions are metastable states. The detailed knowledge of their relaxation processes is therefore of practical importance to improve the laser performance. In this study the diffusion and electron-collisional de-excitation processes for the metastable copper atoms were investigated, which determine the lifetime of the metastable atoms in the discharge.Copper vapor was produced in a discharge tube with a copper hollow cathode by cathodic sputtering. The diffusion coefficients for metastable copper atoms in Ne and Ar were determined from their density decay in the afterglow measured by using laser absorption spectroscopy. The diffusion coefficients for ground-state copper atoms in He, Ne, Ar were also determined by using absorption spectroscopy with a copper hollow cathode lamp used as a light source. It was found that the diffusion coefficients for the metastable and the ground-state copper atoms w … More ere essentially of the same magnitude, contrary to a reported result.A new method was developed to determine the lifetimes of metastable atoms in a steady-state discharge. The method is based on saturated absorption spectroscopy, in which a strong pump laser beam excites metastable atoms and a weak probe beam measures the reduction of their population due to the pump beam ; the analysis of the results with the aid of rate equations enables one to determine the lifetime of the metastable atoms. As was demonstated by experiments, the long lifetime of metastable atoms prevents the pump beam from causing hole burning in the velocity distribution of the atoms through collisional mixing of the populations with different velocities ; this allows one to use the rate-equation analysis. The obtained lifetime of the metastable copper atoms decreased with increasing discharge current. This indicates that their lifetime is mainly determined by electron-collisional destruction rather than by diffusion. This method of determining metastable-atom lifetime can be combined with electron density and temperature measurements to yield de-excitation rate constant for metastable atoms. Less

在强大且高效的铜蒸气激光器中，较低能级的激光跃迁是亚稳态，因此，详细了解其弛豫过程对于提高激光性能具有重要意义。研究了亚稳态铜原子的激发过程，该过程决定了放电中亚稳态原子的寿命。通过阴极溅射在带有铜空心阴极的放电管中产生铜蒸气。亚稳态铜的扩散系数。 Ne 和 Ar 中的原子是通过使用激光吸收光谱测量的余辉中的密度衰减来确定的。He、Ne、Ar 中基态铜原子的扩散系数也通过使用铜空心阴极灯的吸收光谱来确定。结果发现，亚稳态和基态铜原子的扩散系数基本上相同，这与报道的结果相反。开发了一种新方法来确定亚稳态原子的寿命。一个该方法基于饱和吸收光谱，其中强泵浦激光束激发亚稳态原子，弱探测光束借助结果分析来测量其粒子数量的减少；速率方程使人们能够确定亚稳态原子的寿命，正如实验所证明的那样，亚稳态原子的长寿命可以防止泵浦光束通过不同速度的粒子群的碰撞混合而在原子的速度分布中引起烧孔。这使得人们可以使用速率方程分析来获得亚稳态铜原子的寿命随着放电电流的增加而减少，这表明它们的寿命主要由电子碰撞破坏决定，而不是由扩散决定。寿命可以与电子密度和温度测量相结合，得出亚稳态原子的去激发速率常数。