Enhanced high-harmonic generation from chromium-doped magnesium oxide

High-order harmonic generation (HHG) from crystals offers a new source of coherent extreme ultraviolet (XUV) attosecond radiation.Comment: Significant change of conten

Investigating the optical behavior of electrochemically passivated highly doped n-InP with PPP nanofilm

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Spectral control of high order harmonics through non-linear propagation effects

International audienceigh harmonic generation (HHG) in crystals has revealed a wealth of perspectives such as all-optical mapping of the electronic band structure, ultrafast quantum information, and the creation of all-solid-state attosecond sources. Significant efforts have been made to understandthe microscopic aspects of HHG in crystals, whereas the macroscopic effects, such as non-linear propagation of the driving pulse and itsimpact on the HHG process, are often overlooked. In this work, we study macroscopic effects by comparing two materials with distinct optical properties, silicon (Si) and zinc oxide (ZnO). By scanning the focal position of 85 fs duration and 2.123 lm wavelength pulses inside thecrystals, (Z-scan) we reveal spectral shifts in the generated harmonics. We interpret the overall blueshift of the emitted harmonic spectrumas an imprint of the spectral modulation of the driving field on the high harmonics. This process is supported with numerical simulations.This study demonstrates that through manipulation of the fundamental driving field through non-linear propagation effects, precise controlof the emitted HHG spectrum in solids can be realized. This method could offer a robust way to tailor HHG spectra for a range ofapplications

Enhanced extreme ultraviolet high-harmonic generation from chromium-doped magnesium oxide

International audienceHigh-order harmonic generation (HHG) from crystals is emerging as a new ultrashort source of coherent extreme ultraviolet (XUV) light. Doping the crystal structure can offer a new way to control the source properties. Here, we present a study of HHG enhancement in the XUV spectral region from an ionic crystal, using dopant-induced vacancy defects, driven by a laser centered at a wavelength of 1.55 lm. Our numerical simulations based on solutions of the semiconductor Bloch equations and density-functional theory are supported by our experimental observations and demonstrate an increase in the XUV high harmonic yield from doped bulk magnesium oxide (MgO) compared to undoped MgO, even at a low defect concentration. The anisotropy of the harmonic emission as a function of the laser polarization shows that the pristine crystal's symmetry is preserved. Our study paves the way toward the control of HHG in solids with complex defects caused by transition-metal doping

Enhanced high-harmonic generation (HHG) from Cr-doped MgO crystals

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