Gain and saturation energy characteristics in transversely excited N2 lasers

Abstract

Measurements for laser parameters (i.e., small signal gain, g0, and saturation energy density, Es) have been carried out in a transversely excited N2 laser with a variable electrode gap separation, using an arrangement based on an oscillator-amplifier laser system. Our measurements indicate that the measured g0 and Es parameters depend on the electrode gap separation, and thereby the relevant characteristic curves showing this dependency, and consequently the g0 and Es dependencies on the E∕p value or electron temperature in the laser amplifier are introduced. It was also found experimentally that in the present system with the corona preionization, the product of the optimum N2 gas pressure and the gap separation is a constant value of 54Torrcm, where it is valid only for a system operating in a rather small range of electrode gap separation where the laser output power is maximized. Therefore, we show that the pd product is playing an important role for optimized performances of transversely excited N2 lasers. At last, the g0 and Es measurements across the amplifier discharge width have shown that the g0 parameter is not uniformly distributed within the discharge electrode gap separation, while the Es parameter has a minimum at the gap center with a symmetrical distribution of the output energy density.