Highly advanced high harmonic coherent soft x-ray laser sources towards a water window region using laser-ablated solid target plasma

摘要

We have demonstrated the generation of high harmonics (HHs) by using a laser-ablation plume. As a quite novel phenomenon, a single harmonic enhancement has ob­tained by using laser-ablation plumes with a strong oscil­lator strength transition material. We attribute the strong enhancement of single harmonic to multiphoton reso­nance with a strong radiative transition of the ion. For extending cut off energy of HH, we have observed the extension of the cut off energy in HHG by using the dou­bly charged ions. This scheme looks like very much prospective to explore water window region.