Investigation on properties of surface discharge plasma induced shockwave

The XeF(CA) laser has many potential applications in laser underwater detecting due to the fact that its wavelength located in 450~520 nm band is the best propagating window in atmosphere and sea. The technique of surface discharge optical pumping possesses many advantages, such as intense violet and vacuum-violet radiation, relatively low charge voltage, non-essential high current switch, high temperature and high repetition rate, and easy realization in technique. Therefore it becomes a highly efficient pumping for Xe(CA) laser. Intense shockwave is generated during the expansion of plasma induced by surface discharge. The intense shockwave results in the turbulence of homogeneity and refractive index of active medium, and impacts on the output of XeF laser consequently. Therefore, it is important to study the properties of generation and propagation of the shockwave. By employing a pressure sensor, properties of the shockwave measured at various spots and discharge voltages are analyzed. The results indicate that the duration of the shockwave, followed by a relatively weaker pressure wave, is in the ms range. The higher the charge voltage and the more the released energy, the higher the peak pressure of the shockwave with the maximum pressure of up to 1 MPa, the more the peak position delayed, and the longer the duration. The research points out a direction for improving the output stability of XeF(CA) laser at relatively high repetition rate.