We report a power-enhanced nitrogen laser system which utilizes an autopreionization effect at the sharp edges of the Blumlein capacitor’s electrode. The power enhancing effect of the laser is investigated at various autopreionizer gap distance and the main electrode gap distance. A 43% increase and a stability within 2% in the laser output power are achieved at the optimal configuration. The present autopreionization technique is found to be simple yet more effective.

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An injection-locked XeCl excimer laser with a modified positive-branch confocal unstable resonator was developed and the output characteristics were investigated. We utilized the hemiconfocal scheme in the line-narrowed oscillator in order to obtain a seed beam with high energy as well as narrow linewidth. In this case we obtained 0.05 cm-1 linewidth with 10 µ J output energy. The maximum output energy of the injection-locked oscillator was 110 mJ, which is 15% greater than that with free-running oscillation. We also presented a new method which can simply measure the power gain of the amplifier, by which the small signal gain coefficient of the amplifier was measured to be 10%/cm.

A simple modification of the output coupler to a standard positive-branch confocal unstable resonator (PBUR) was proposed and the output characteristics were investigated and compared with those of the standard PBUR. We utilized a small convex mirror of 1.8 mm diameter as an output coupler in order to reduce the beam divergence and to eliminate the subsidiary spot caused by the Fresnel reflection effect in the standard PBUR. We obtained a single spot in the focal plane with a nearly diffraction-limited beam divergence of 0.09 mrad.

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