Transient gain phenomena and gain enhancement in a fast-axial flow CO2 laser amplifier

The transient gain phenomena observed in a fast-axial flow CO2 laser amplifier are theoretically explained by taking into account a gas temperature T and an inverted population ratio n2/n1 as a function of discharge time. Expressing the transient gain as a function of the gas-flow velocity v and the discharge current Idis including their spatial distribution along the radial direction of a plasma tube , both the transient power-decrease jP and transient time required to be a stable value are formulated with respect to a plasma length tst and an input probe power P , being well consistent with the corresponding experiments . Possibilities of improving these transient behavior are also demonstrated by cooling a plasmatube wall and a gold catalyst.