Soft X-ray emission from molybdenum plasmas generated by dual laser pulses

We demonstrate efficient enhancement of soft X-ray (SXR) emission from molybdenum plasmas produced using dual pulse irradiation, in which 10-ns and 150-ps pre-pulses were followed by a 150-ps main pulse. The number of photons was observed to be 5.3 × 10¹⁶ photons/sr, which corresponded to a conversion efficiency of 1.5%/sr in λ = 2.34-4.38 nm region at a pulse separation time of 1 ns with the 150-ps pre-pulse. The conversion efficiency became 1.3 times as large as that produced by a single pulse. The results indicate the advantage of dual pulse irradiation using sub-ns pre-and main pulses to produce the bright plasmas required for applications such as laboratory based SXR microscopy.