Attosecond soft X-ray high harmonic generation

• Published in: Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences Vol. 377; no. 2145; pp. 1 - 12
• Main Authors: Johnson, Allan S., Avni, Timur, Larsen, Esben W., Austin, Dane R., Marangos, Jon P.
• Format: Journal Article
• Language: English
• Published: Royal Society 20-05-2019
• ISSN: 1364-503X; 1471-2962

High harmonic generation (HHG) of an intense laser pulse is a highly nonlinear optical phenomenon that provides the only proven source of tabletop attosecond pulses, and it is the key technology in attosecond science. Recent developments in high-intensity infrared lasers have extended HHG beyond its traditional domain of the XUV spectral range (10–150 eV) into the soft X-ray regime (150 eV to 3 keV), allowing the compactness, stability and sub-femtosecond duration of HHG to be combined with the atomic site specificity and electronic/structural sensitivity of X-ray spectroscopy. HHG in the soft X-ray spectral region has significant differences from HHG in the XUV, which necessitate new approaches to generating and characterizing attosecond pulses. Here, we examine the challenges and opportunities of soft X-ray HHG, and we use simulations to examine the optimal generating conditions for the development of high-flux, attosecond-duration pulses in the soft X-ray spectral range.
This article is part of the theme issue ‘Measurement of ultrafast electronic and structural dynamics with X-rays’.