紫外レーザー導光システムの開発

Abstract

The suitable tools for the UV laser power delivery have not been developed yet. In an effort to make efficient delivery of UV laser, we have proposed the hollow light guide which consists of an aluminum-phosphor bronze reflector and a teflon E-type rail spacer. The delivery characteristics of the hollow light guide have been investigated using the ArF and KrF excimer lasers. In case of the KrF laser, the transmittance and delivery energy reached 78%/m and 100mJ/pulse, respectively. In the ArF laser, the transmittance and delivery energy were obtained to be 56%/m and 40mJ/pulse, respectively. It is known that 193nm radiation by the ArF laser are absorbed by the air. The transmittance and the delivery energy were obtained to be 72%/m and 45mJ/pulse using helium-filled hollow light guide, which were greatly improved for comparison with the case of the air. In this reports, the method of manufacture of the reflectors was improved. We have also tried the quartz fiber with OH ion doped core. In the initial and several pulse operation, the transmittance was obtained over 80%/m. The transmittance was decaying with the repetitive pulse delivery until about 35%/m. But, the transmittance was recovered under the room temperature