The laser plasma behavior of the RF exited CO2 laser in a pulse operation: an acoustic approach

Abstract

An acoustic wave changes, by definition, the pressure of the gas medium. The power delivered to the pulsed gas laser changes the pressure (and temperature) of the laser medium. The monitoring of the acoustic wave in the laser cavity, taken as a specific acoustic resonator, can be an easy measure of the local changes of the laser gas pressure. The changes of the pressure involve changes of the laser gas density, and changes of the refractive index, as a consequence. It leads to a frequency tuning of the laser optical resonator. In the case of the CO2 laser a rotational line hopping phenomenon is observed as a result. In other words, a single frequency operation of the RF excited CO2 laser with a pulsed plasma is problematic. The main goal of the experiment is to give a picture of the laser plasma behavior during the pulsed excitation of the CO2 laser medium.