Abstract
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. 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.
Original language | English |
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Pages (from-to) | 257-262 |
Number of pages | 6 |
Journal | Optica |
Volume | 5 |
Issue number | 3 |
DOIs | |
State | Published - Mar 20 2018 |
Funding
U.S. Department of Energy (DOE), Office of Science (SC), Basic Energy Sciences (BES) (DE-FG02-04ER15592). We acknowledge the use of the CUCSU Summit Computer Facility to conduct the simulations, NSF (ACI-1532235). M. Berrill acknowledges Oak Ridge National Laboratory. This paper has been authored by UTBattelle, LLC, under contract DE-AC05-00OR22725 with the U.S. Department of Energy (DOE). Funding. U.S. Department of Energy (DOE), Office of Science (SC), Basic Energy Sciences (BES) (DE-FG02-04ER15592). Acknowledgment. We acknowledge the use of the CU-CSU Summit Computer Facility to conduct the simulations, NSF (ACI-1532235). M. Berrill acknowledges Oak Ridge National Laboratory. This paper has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the U.S. Department of Energy (DOE).