Measurement of Laser Generated Plasma Parameters through the Perturbation caused by the plasma in a stationary electric field

VILLAGRÁN-MUNIZ, MAYO; SÁNCHEZ-AKÉ, C.; PALLESCHI, V.; BREDICE, FAUSTO

Pîsa

Simposio; 9th Euro-Mediterranean Symposium on LIBS; 2017

When a high power pulsed laser pulse is focused in air or in solid targets placed between the plates of a planar charged capacitor, the plasma generates a transient redistribution of the electrical charges on the plates that can be easily meas-ured as a voltage drop across a resistor connected to the ground plate. This signal is proportional to the capacitor applied voltage, the distance between the plates and the total number of ions removed by breakdown which in turn is related to the laser energy deposited in the breakdown process and the electron density of the plasma. In this work we show that the electrical signal measured on the resistor is univocally related to the consumed energy during the breakdown process, the electron density of the plasma and the ablated mass from the target. Therefore, after a proper calibration depending on the material and the experimental geometry, the peak of the electrical signal can be used for real time quantitative measure-ment of the above mentioned parameters in pulsed laser generated plasma experiment