Employing the inner-shell transition mechanism is a potentialway to obtain ultra-short wavelength lasers. It is not a hopeless dream to produce an ultra-short wavelength hard X-ray laser using thismechanism, in light of the recent great developments in ultra-fast and ultra-intense laser technology as well as experimental X-ray laser research. In this paper the principle of inner-shell X-ray lasers is introduced and some possible approaches to the realization of such lasers are discussed in detail.

从泵浦光与腔模的空间匹配函数出发，讨论了泵浦光的发散角、焦点位置等因素对激光系统效率的影响。发现在旁轴近似下，匹配函数的最大值随泵浦光发散角的增大而增大，在考虑到像散的影响后，得到泵浦光发散角的参考值。