Research On Plasma Characteristics Of Germanium Ablated By Femtosecond Laser

In recent years, there are more research to the laser ablation. Mainly by changing the experiment of pulsed laser parameters and different target. Also some by changing the parameters of gas environment research, To study the characteristics of laser induced plasma evolution. At this stage for laser ablation of metal plasma characteristics of target material research is more. For the laser ablation of semiconductor materials research is relatively small. Ge is a semiconductor material. In areas such as solar cells and optical fiber communication have played a vital role. And has extraordinary development prospects in fighting in photoelectric. Provides a strong technical foundation for military industry. So we need more understand and master of plasma characteristics of femtosecond laser ablation on Ge.In this thesis, the conditions of different environmental, the characteristics of laser-induced plasma was carried out based on the study on the spectrum of laser-induced germanium plasma. The main work is divided into three areas:The germanium target was irradiated by femtosecond pulse laser at the wavelength of800nm in different environmental. The laser pulse width of100fs and the repetition frequency of1kHz.In air environment, and the influence on the characteristics of laser-induced germanium plasma was studied using time-space resolved emission spectroscopy method. We change the laser energy, spectral intensity with time-space evolution characteristics were given. The electron temperature and electron density with time evolution characteristics were given. And the electron temperature and electron density with energy evolution characteristics were given.In vacuum condition, we was studied using time-space resolved emission spectroscopy method, under the different pressures, spectral intensity with time-space evolution characteristics were given. The electron temperature and electron density with time evolution characteristics were given. And the electron temperature and electron density with pressures evolution characteristics were given.In different gases (Ar, He) environment, we was studied using time-space resolved emission spectroscopy method, under the different pressures and different gases environment,, spectral intensity with time-space evolution characteristics were given. The electron temperature and electron density with time evolution characteristics were given. And the electron temperature and electron density with pressures and different gases evolution characteristics were given.