Ultrafast coherent XUV radiation from a laser-plasma-accelerated electron beam

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This project aims toward developing an ultrafast (femtosecond), coherent, extreme ultraviolet (XUV) radiation source using beams produced by a laser-plasma-based accelerator. Coherent radiation can be generated via the free-electron laser (FEL) mechanism by coupling the ultra- short laser-plasma-accelerated electron beam into a conventional magnetic undulator, provided the e-beam quality is sufficientThe project consists of three phases: (1) measurement of undulator radiation to characterize electron beam properties (energy spread and emittance) for demonstrating their suitability as FEL drivers, (2) development of beam transport system to match the electron beam from the plasma accelerator to the magnetic undulator, and (3) measurement of FEL radiation gain. This work has direct implications for radiation source development for, compact, next-generation light sources. The proposed work will demonstrate for the first time an FEL driven by a laser-plasma accelerated electron beam, enabling extremely compact sources of coherent, high peak power, radiation. The traditional approach to drive an FEL is to use a conventional RF accelerator. Since the accelerating gradient in an RF linac is typically limited to tens of MV/m, the size and cost of a GeV-class accelerator is large. Plasma accelerators, on the other hand, can support accelerating gradients greater than 100 GV/m. Consequently, the size and cost of a laser-driven accelerator can be relatively small, e.g., the size of the accelerating plasma structure required to reach GeV energies is only several centimeters in length. In addition, the electron bunches emerging from a laser-plasma accelerator are naturally short (of the order of ten femtoseconds, determined by the plasma wavelength), and intrinsically synchronized to the laser driver, making such a source ideal for ultrafast science applications. Understanding the structural dynamics of materials on fundamental atomic timescale represents an important research frontier. Development of a compact source of femtosecond, energetic XUV radiation would allow novel experiments exploring chemical reactions and phase transitions of materials, as well as nanoscale physics and ultrafast phenomena. The grant will support two graduate students and one post-doctoral Research Associate.