Compact gain-saturated x-ray lasers down to 685 nm and amplification down to 585 nm

Alex Rockwood, Yong Wang, Shoujun Wang, Mark Berrill, Vyacheslav N. Shlyaptsev, Jorge J. Rocca
2018 Optica  
Plasma-based x-ray lasers allow single-shot nano-scale imaging and other experiments requiring a large number of photons per pulse to be conducted in compact facilities. However, compact repetitively fired gain-saturated x-ray lasers have been limited to wavelengths above λ 8.85 nm. Here we extend their range to λ 6.85 nm by transient traveling wave excitation of Ni-like Gd ions in a plasma created with an optimized pre-pulse followed by rapid heating with an intense sub-picosecond pump pulse.
more » ... second pump pulse. Isoelectronic scaling also produced strong lasing at 6.67 nm and 6.11 nm in Ni-like Tb and amplification at 6.41 nm and 5.85 nm in Ni-like Dy. This scaling to shorter wavelengths was obtained by progressively increasing the pump pulse grazing incidence angle to access increased plasma densities. We experimentally demonstrate that the optimum grazing incidence angle increases linearly with atomic number from 17 deg for Z 42 (Mo) to 43 deg for Z 66 (Dy). The results will enable applications of sub-7 nm lasers at compact facilities.
doi:10.1364/optica.5.000257 fatcat:qpobwohckjhsna5zci6f7rmoii