An Approach to the Generation of Uniform Line Foci for Use in X-Ray Laser Experiments

Abstract

We report on the results of an investigation into the generation of uniform line foci suitable for use in the generation of X-ray lasers. Our approach involves the use of specially designed apertures, whose shape depends on the beam profile and the focussing optics, the apertures limit the intensity to a predetermined level at each point along the line focus, thus generating a uniform line focus at the expense of some of the overall beam energy. A ray tracing code was written specifically to find the required aperture shapes. The code currently supports only line foci generated by off-axis spherical mirrors but is able to accommodate arbitrary beam profiles. As high energy lasers become more accessible (and hence pump energy becomes less of an issue), then due to their low cost and ease of implementation, these apertures are an appealing method of controlling the intensity profile of a line focus when overall efficiency of the pump system is not a governing factor.