Proposal of a longitudinally pumped saturated Ni-like Mo ion x-ray laser at 18.9 nm

We reexamine the transient gain scheme in this paper and develop this scheme with a new pumping geometry for designing a compact and highly efficient Ni-like Mo ion soft-x-ray laser. Model calculations show that a saturated amplification of soft x rays at 18.9 nm can be realized by using a 1.05 mu m driving laser with only several hundred millijoule energy in a picosecond pulse. We propose a longitudinally pumping geometry for the high transient gain x-ray laser, in order to improve the pumping efficiency and to overcome some limitations of the present transient gain laser.