Abstract

High harmonic generation (HHG) in gas occurs when atoms are excited by an intense laser field. This technique enables to generate short coherent and directional extreme UV (XUV) radiation. Due to these unique properties, HHG presents a promising source for many applications such as time-dependent XUV spectroscopy. So far, mainly high energy systems such as Ti-sapphire laser amplifier have been used but are associated with a low repetition rate (a demonstration has been still reported at 100 kHz [1]). However, some applications require detecting in practice one event per 10 shots or less [2]. With low repetition rate systems, acquisition times may become unacceptable for recording exploitable statistics. Fiber laser-based HHG technology offers now the possibility to drive such experiments at high repetition rate. Indeed, it has been demonstrated that Yb-doped fiber chirped-pulse amplification (FCPA) systems can deliver both high average power and high energy subpicosecond laser pulses at higher repetition rate (100 kHz – 1 MHz) with good enough characterization for HHG [3,4]. Very high harmonics were recently observed despite moderate conversion efficiency [5].

© 2011 Optical Society of America