Статья

Experimental and theoretical studies of two-color-pump resonance-induced enhancement of odd and even harmonics from a tin plasma

R. A. GaneevBlackett Laboratory, Imperial College London, London SW7 2BW, United KingdomV. V. StrelkovA. M. Prokhorov General Physics Institute of RAS, Vavilova street, 38, Moscow, RussiaC. HutchisonBlackett Laboratory, Imperial College London, London SW7 2BW, United KingdomA. ZaïrBlackett Laboratory, Imperial College London, London SW7 2BW, United KingdomDeirdre KilbaneSchool of Physics, University College Dublin, Belfield, Dublin 4, IrelandMargarita KhokhlovaA. M. Prokhorov General Physics Institute of RAS, Vavilova street, 38, Moscow, RussiaJ. P. MarangosBlackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom

2012en

ABI

Аннотация

We study high-order harmonic generation from a laser-produced tin plasma using 780 and 390 nm, 40 fs, 1 kHz pulses. Varying the chirp of the laser radiation, we observe variation of the harmonic frequency and intensity. The enhanced 16th and 17th harmonics are attributed to the influence of the strong ionic transitions of tin. Theoretical calculations of the photoabsorption spectra reveal the decisive role of Sn ii and Sn iii transitions in the enhancement of single harmonics. Varying the fundamental frequency we study numerically the spectral width where the harmonic is enhanced. We find, both theoretically and experimentally, that this width is wider than the one of the corresponding resonance in the photoabsorption spectrum. The resonance line modification can be explained by the Stark shift of the autoionizing state in the laser field, as well as the photoionization of this state.

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Идентификаторы

DOI: 10.1103/physreva.85.023832

Цитирования и источники

Цитирований: 12Использованных источников: 0

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