Effect of laser energy on laser-induced plasma confined by a hemispherical cavity

To study the influence of laser energy on the enhancement characteristics of plasma confined by a hemispherical cavity, the time-resolved spectra of the plasma with and without confinement under different laser energies were collected. When the laser energy exceeded 80 mJ, the spectral line intensity was enhanced significantly at the delay time range of 8-14 mu s. Significantly, the maximum enhanced factor increased with the increase in the laser energy, while the corresponding delay time decreased gradually. These results indicated that when a laser pulse with relatively high energy is used to ablate the sample, a strongly reflected shockwave will be generated to compress the plasma, resulting in a significant enhancement effect at an early stage. Comparing the distributions of the plasma temperature, it was found that the plasma confined by a hemispherical cavity could maintain a relatively high temperature for a long period, resulting in spectral enhancement.

Automated summary

Experimental results showed that when the laser energy exceeded 80 mJ, the spectral line intensity of confined plasma was significantly enhanced at a delay time of 8-14 μs, with a higher energy leading to a greater enhancement effect. Confined plasma within a hemispherical cavity could maintain a relatively high temperature for an extended period, resulting in prolonged spectral enhancement.