Efficient picosecond x-ray pulse generation from plasmas in the radiation dominated regime
Date
2017-10-27
Authors
Hollinger, Reed, author
Bargsten, Clayton, author
Shlyaptsev, Vyacheslav N., author
Kaymak, Vural, author
Pukhov, Alexander, author
Capeluto, Maria Gabriela, author
Wang, Shoujun, author
Rockwood, Alex, author
Wang, Yong, author
Townsend, Amanda, author
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Abstract
The efficient conversion of optical laser light into bright ultrafast x-ray pulses in laser created plasmas is of high interest for dense plasma physics studies, material science, and other fields. However, the rapid hydrodynamic expansion that cools hot plasmas has limited the x-ray conversion efficiency (CE) to 1% or less. Here we demonstrate more than one order of magnitude increase in picosecond x-ray CE by tailoring near solid density plasmas to achieve a large radiative to hydrodynamic energy loss rate ratio, leading into a radiation loss dominated plasma regime. A record 20% CE into hν > 1 keV photons was measured in arrays of large aspect ratio Au nanowires heated to keV temperatures with ultrahigh contrast femtosecond laser pulses of relativistic intensity. The potential of these bright ultrafast x-ray point sources for table-top imaging is illustrated with single shot flash radiographs obtained using low laser pulse energy. These results will enable the deployment of brighter laser driven x-ray sources at both compact andlarge laser facilities.
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Subject
laser light
laser materials
laser plasmas
pulse generation
radiative processes
x ray lasers