Title :
Theoretical analysis of transient gain phenomena in a fast-axial flow type CO/sub 2/ laser amplifier
Author :
Tsuchida, Eiichi ; Sato, Heihachi
Author_Institution :
Dept. of Electr. Eng., Nat. Defense Acad., Yokosuka, Japan
Abstract :
A decrease of output power observed after discharging plasma tubes in a fast-axial flow CO/sub 2/ laser amplifier with a short dwell time of about 1 ms is discussed. For the 10P(18) line at 50 torr pressure, the small-signal gain goes from 1.308/m to 1.068/m within 135 s after discharging the plasma tubes, for a gas-flow velocity of 180 m/s and discharge current of 60 mA. The fraction of power decrease is about 15% for the plasma length of 80 cm and the input power of 5 W. Dependences of the observed fraction of power-down and the transient time to reach a stable power on input power and plasma length are theoretically analyzed by introducing the CO/sub 2/ dissociation factor as a function of gas-flow velocity, discharge current and plasma length, and gain saturation, resulting in good agreement between the experimental results and computation.<>
Keywords :
carbon compounds; discharges (electric); gas lasers; 5 W; 50 torr; 60 mA; 80 cm; CO/sub 2/ dissociation factor; CO/sub 2/ laser amplifier; discharge current; fast-axial flow; gain saturation; gas-flow velocity; output power; plasma length; plasma tube discharging; small-signal gain; transient gain phenomena; Electron tubes; Gas lasers; Laser theory; Plasma stability; Plasma temperature; Power amplifiers; Power generation; Power lasers; Thermal conductivity; Transient analysis;
Journal_Title :
Quantum Electronics, IEEE Journal of
