Note: Measurement for the disturbance of discharge medium in pulsed gas laser

Abstract

In this paper, a single-filament schlieren system equipped with a four-element photodiode was developed to investigate the disturbance in the discharge region of a pulsed gas laser. This method showed a high sensitivity in measuring weak disturbance left in the test region. Therefore, it was applied in a discharge-pumped ArF excimer laser for the acquiring of optical disturbance of the gas medium in the directions of pulsed discharge and gas flow simultaneously. Time-resolved signals of the optical disturbance were recorded for each pulse. A quantitative evaluation for the strength of residual disturbance was obtained from the differential output of the four-element photodiode, and the influence of the disturbance on the pulsed energy was also analyzed. It showed that this method can be easily applied in pulsed gas laser to study the effect of the gas non-uniformity on beam parameters.

A single-filament schlieren method for flowing characteristic measurements in the pulsed gas lasers

“…With the increase of the repetition rate, the possible time for gas restoration is reduced and the excimer laser is working on the condition of higher non-uniformity. So the non-uniformity of gas density would increase with repetition rate and it would reduce the output energy [18]. …”

“…In this paper, we demonstrate a single-filament schlieren method using four-element photodiode to measure the flowing characteristics of the high-repetition-rate ArF excimer laser [18]. The effects of electromagnetic interference (EMI) and the vibration of the blower on the output of the photodiode were investigated in detail.…”