Analysis of the discharge plasma impedance of copper vapor laser

Abstract

In the pursuit to analyze the impedance of copper vapor lasers (CVLs) in different conditions, a novel approach has been proposed in this paper. The underdamped behavior of the voltage waveform across the CVL is leveraged to compute the impedance of high-voltage discharge plasma in the laser. This methodology provides an accurate idea of the discharge plasma resistance and inductance as it is calculated on the basis of experimental voltage waveforms obtained from the laser system. The laser head inductance remains almost fixed and equivalent to ∼0.47 µH whereas the laser resistance changes between 34 Ω and 11 Ω depending on the discharge condition and its constituents. A critical evaluation of CVL impedance is done in all experimentally possible conditions, and a methodology has been proposed to maintain the CVL impedance, which results in the power stability of the laser in oscillator–amplifier configuration. The laser impedance variation w.r.t. time, pressure, operating voltage and electrode pin configuration has been investigated. The impact of the localized electric field at the electrode on the laser resistance has also been emphasized in this paper. A good concurrence exists between the calculated laser impedance and its experimental behavior.