Efficient extreme ultraviolet emission from one-dimensional spherical plasmas produced by multiple lasers.

We demonstrate high conversion efficiency for extreme ultraviolet (EUV) emission at 6.5–6.7 nm from multiple laser beam-produced one-dimensional spherical plasmas. Multiply charged-state ions produce strong resonance emission lines, which combine to yield intense unresolved transition arrays (UTAs) in Gd, Tb, and Mo. At an optimum laser intensity of 1 × 10¹² W/cm², which is estimated to yield an electron temperature of around 100 eV, the maximum in-band EUV conversion efficiency (CE) was observed to be 0.8%, which is one of the highest values ever reported due to the reduction of plasma expansion loss. [ABSTRACT FROM AUTHOR]