Attractive Role of Hydrogen in TEA CO2 Lasers: Improving Discharge Stability and Output Characteristics

Abstract

Hydrogen contained in the gas mixture of transversely excited atmospheric-pressure (TEA) CO₂ lasers plays an attractive role in improving the discharge stability and output characteristics of glow discharge by suppressing arc discharge. During the excitation of TEA CO₂ lasers, hydrogen effectively relaxes the CO₂ (010) level, with the action of inhibiting the O₂ production by dissociating CO₂ molecules, thus reducing the “bottleneck” in the operation of laser systems. We propose a new method that takes into account the role of hydrogen in the whole process from pumping to output of TEA CO₂ lasers. We numerically evaluate the transition from glow to arc discharge in the discharge gap of TEA CO₂ lasers. The current and voltage (V–I) differential equations of the pumping circuit in TEA CO₂ lasers using corona pre-ionization are solved to determine the O₂ concentration produced by the change in electron density. Then, the six-temperature model is combined to simulate the dynamics of high-power TEA CO₂ lasers considering the change in gas mixtures with hydrogen. The determined discharge voltage and gas mixture are essential for designing and operating TEA CO₂ lasers for suitable applications.