| 摘要 |
PURPOSE:To permit pulsed gas laser to transmit between one pair of the two pairs of discharging electrodes arranged in the oscillation direction of the pulsed gas laser and provide uniform preionization effects by permitting the other pair of discharging electrodes to generate pulse discharge in advance. CONSTITUTION:Discharging electrodes 21 and 22 are permitted to generate pulse discharge by a discharge controller 33 and the other discharging electrodes 23 and 24 are permitted to generate pulse discharge after a certain time within the pulse discharge width. Thus, uniform preionization is allowed between the discharging electrodes 23 and 24 by the previous excimer laser oscillation and high preionization density and uniformity are ensured between the discharging electrodes 23 and 24 and high conversion efficiency of the excimer laser is provided even when it is operated by high repeating number. Since the timing of the succeeding pulse discharge is set in the previous pulse discharge width, the succeeding pulse discharge is generated in a stabilizing area even when the pulse discharge previously generated becomes unstable, and the excimer laser can generate a laser pulse by stable operation. |
