Research On 46.9nm Laser Pumped By Capillary Discharge With Current Amplitude 26kA And 32kA

X-ray laser not only has the common advantage of other wavelength laser, but also has particular characteristics, such as short wavelength, high single photon energy and instantaneous pulse power, so there is a good prospect in many micro fields. Compared to many kinds of schemes for the realization of X-ray laser, the capillary discharge-pumped desktop X-ray laser scheme made the great progress of the miniaturization and practicality X-ray lase. In this paper, we mainly study the variation regularity of the Ne-like Ar 46.9nm laser characteristics produced by different amplitude current discharged in capillary with 4.0mm diameter. By combining theory with experiment, the experimental parameters of higher amplitude and better beam quality have been obtained.In theory, the plasma state generated of the Z-pinch process was simulated by using one dimensional magneto hydrodynamics model. We analyzed the changes of the plasma state by controlling the amplitude of the main pulse current and the initial argon gas pressure. From the simulation results, we obtained the influence that is cause by different amplitude main pulse current and different initial pressure on the Z- pinch process. we also analyzed the regularity of important parameters, including electron temperature, electron density, ion abundance and so on, in different experimental conditions at the laser generated time. By further combining with the relevant literature and the subsequent experimental results, the suitable plasma state for laser amplification was obtained.In the experiment, the 26 k A and 32 k A amplitude of the main pulse were chosen.Appropriately improving the amplitude of main pulse, the amplitude of laser output was increased by 2 times, and energy of laser output had a substantial increase. Under the two current conditions, We studied the influence of initial Ar pressure and different change rate of pre-pulse on the intensity of the laser, in order to find optimal conditions for laser amplification. Under optimum condition, We measured the gain coefficient in two current amplitude. And both of them obtained gain saturation. The gain coefficient of the two currents were almost the same, the spontaneous radiation intensity of unit length increased under high current condition, which makes the laser output of high amplitude current could reach a higher level.Based on the application value of X-ray laser, we researched on the spatial distribution of laser intensity. the experimental scheme was that Ce:YAG transformed the 46.9nm laser into visible light and captured by camera. The ring laser facula was obtained under the condition that the laser output was the most powerful. Changing theinitial pressure, we observed the law of laser facula with the change of initial pressure from the pressure most suitable laser amplification. We found that increasing the pressure and reducing the pressure got different change laws of facula shape. The beam divergence angle of the laser facula was calculated by the geometric method, and the variation of the beam divergence angle with the pressure was summarized.