Development of short-wavelength soft-X-ray lasers with a high repetition rate

Optimizing the target design in order to make use of the maximum gain region is very important in view of improving the overall efficiency of a soft-X-ray laser. The required density profile good for minimizing refraction and amplification losses is difficult to achieve in laser-heated blow-off plasma from planar targets. In order to exploit the peak gain region in a transient collisional excitation scheme (TCE) laser system, we have proposed a simple longitudinal pumping scheme. High repetition rate is therefore possible due to its low energy consumption in the design. This pumping mode has several merits: the high pumping efficiency inherent from the longitudinal pumping geometry, the perfect travelling wave pumping which is vital for the TCE laser and the directly sampling the desired gain region of a suitable density.