Incoherent and coherent extreme ultraviolet emission from boron plasma

The search for reliable sources of incoherent and coherent extreme ultraviolet (XUV) radiation in different spectral ranges is an important task in laser physics. Here we report on the incoherent emission of XUV radiation in the region of 6 nm from boron plasma. The optimization of target ablation allowed the generation of XUV emission mainly originated from a single B IV transition (lambda = 6.03 nm). We also demonstrate the generation of the 806 nm radiation harmonics up to the 55th order (lambda = 14.6 nm) and of tunable near infrared radiation (1280-1400 nm) up to the 35th order (lambda=38 nm), during the propagation of femtosecond pulses through boron plasma. The incoherent and coherent emissions from this target were compared and analyzed considering the influence of ionic transitions on the B IV emission and harmonic efficiency. We present different schemes of laser-plasma interaction (two-color pump of B plasma, generation of tunable harmonics in XUV range, formation of structured extended plasma, ablation of boron nanoparticles, laser-induced breakdown spectroscopy, overheating of boron targets, quasi-phase matching of plasma harmonics, etc.) during the ablation of boron-containing targets.