Physics Journal of the Indonesian Physical Society
COMPARISON OF CONFINEMENT EFFECT IN ENHANCING SHOCK WAVE PLASMA GENERATION AT LOW PRESSURE BETWEEN TEA CO2 AND ND-YAG LASERS ON QUARTZ SAMPLE
Rinda Hedwig1, Tjung Jie Lie2 and Hendrik Kurniawan2
1Hardware Laboratory, Bina Nusantara University
Jl. KH. Syahdan 9, Jakarta 11480, Indonesia
2Applied Spectroscopy Laboratory, Graduate Program in Opto-Electrotechniques and Laser Applications
University of Indonesia, Jl. Tomang Raya 51G-H, Jakarta 11440, Indonesia
An experimental study on the pre-irradiation effect observed on quartz sample reveals its origin in the failure of shock wave formation by the ablated atoms at the initial shots. The disappearance of this effect at later stages was found to be connected with the appearance of a crater of appropriate depth created by repeated irradiation on the sample surface. Experimental data show that it is the confinement effect of the crater, which is solely responsible for the generation of the secondary plasma, in conformation with the shock wave plasma model proposed earlier. Further studies show that the lateral size of the crater which is depend on the beam quality of the laser system gives prominent effect in the number of pre-irradiations before the plasma formation. It is concluded that smaller diameter and deeper crater will suppress the number of pre-irradiations.