History of high-intensity interactions: Physics of the power scaling of the 2.9 Angstrom Xe(L) X-ray amplifier to the multi-petawatt level

The article presents experimental results demonstrating Xe(L) spectral hole-burning and corresponding saturated amplification on the X
^e31+
transition array. Xe(L) single-pulse spontaneous emission spectrum was recorded with a CCD equipped von Hamos mica spectrograph. A spectral comparison of the amplified spectrum with the spontaneous emission profile is also presented.