High-order harmonics generation under quasi-phase matched conditions in silver, boron, and silver sulfide plasmas of different configurations

The application of advanced methods for high-order harmonics enhancement allows the formation of conditions for phase matching of the generated harmonics in different ranges of extreme ultraviolet. We demonstrate quasi-phase matching (QPM) of the high-order harmonics generated in the plasmas containing silver microparticles and atoms, and silver sulfide molecules. The groups of harmonics in the range of 30th to 40th orders at QPM conditions prevail over the lower orders of harmonics. In most cases, the lower-order harmonics disappeared from the generated spectra at QPM conditions. The 22x enhancement factor of QPM harmonics and the 3 x 10(-5) conversion efficiency for a maximally enhanced harmonic were demonstrated in the case of silver microparticle-contained plasma in the 47-67 eV energy range. Published under license by AIP Publishing.