High Efficiency Laser-Sustained Plasma Source

Laser-sustained plasma (LSP) featured by high radiance in the ultraviolet (UV) spectral range is found to be powerful in high resolution inspection and spectroscopy applications. In this paper, we demonstrate significant enhancement of power conversion efficiency in LSP excited by focused orthogonal laser beams. The "reservoir" boundary formed by the laser field traps the high temperature zone of the plasma. LSP with UV radiance >20% conversion efficiency has been achieved experimentally, which is the highest reported value to our knowledge. This work paves a novel way of generating high radiance UV sources by spatial manipulation of excitation laser beam.