Abstract

Generally, the small size, stabilization of laser output, high repetition rate and long life operation are required in the laser sources for lidar application.¹ For this purpose, we have developed a compact discharge pumped KrF laser. Figure 1 shows the schematic diagram of the laser. It consists of a compact laser vessel, gas circulation system, and the driving circuit. Charge transfer circuit is used for driving of the laser. The low inductance of main discharge loop is very important for designing the compact laser. The inductance of main discharge loop is designed to 7 nH. Laser discharge volume is about 2 × 1.2 × 54 cm³ and internal gas volume is ~8 liter, which volume is smaller than the volume of other repetition excimer lasers.^2–3 The materials used in its construction have been selected with considerable care for the long life operation. The SUS-304, Alumina Ceramic, and PVDF are used for protecting the reactions with fluorine gas in the chamber. Specially, Alumina Ceramic inserted to block the UV light in reaching on PVDF. A line flow fan (9 × 60 cm²) and a ferro-fluidic seal (3000 rpm Number of maximum rotation) are built for gas circulation. Peacking capacitor is set for obtaining the smooth gas flow at the outside of laser chamber and vane is used for eliminating the whirlpool. The flow loop of laser gas is improved from these results. Flow velocity of 6.3 m/s is obtained at the fan rotation of 3000 rpm in case the laser⁴ which peacking capacitor is inside of chamber. The main reason of slow velocity is due to the disturbance of flow loop by the peacking capacitor. But, The newly developed laser is obtained the fast flow velocity of 13 m/s in which peacking capacitor is set at the outside of the chamber.

© 1995 IEEE