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Pulse compression based on non-linear propagation in a gas-filled hollow core fiber (HCF) is amongst the common techniques to generate few-cycle laser pulses [1]. Although very efficient, the major disadvantage of this method is the need to use expensive noble gases like krypton or xenon to compress low energy pulses [2–4]. Our latest results confirm that certain molecular gases, hydrofluorocarbons, represent an affordable and efficient alternative to the traditional atomic gases [5,6]. Such gases bear the potential to generalize HCF compression to high repetition rate, low intensity laser systems [7].

We study high-order harmonic generation from laser ablated Indium plumes below the ionization potential at various driving laser wavelengths. Apart from intense harmonic from the autoionizing state, we also observe enhanced harmonic generation below the ionization potential.

Using a non-collinear FOPA, a source delivering 1.8 μm, 30 mJ, 13 fs laser pulses is demonstrated. This is the first step towards 100 mJ for ∼10 TW. This laser opens the way for high brightness soft X-ray attosecond pulses.

General restrictions arising from gain-narrowing and phase-matching are circumvented by employing parametric amplification in the frequency rather than the time domain. Frequency-domain OPA has been used for amplifying few-cycle pulses and for high gain amplification.

Recent advances in optical parametric amplification (OPA) based few-cycle pulse generation at 1.8 µm wavelength led to the discovery of multi-electron correlation effects in high harmonic generation (HHG), in particular the giant resonance in Xe. The novel scheme for sub-two cycle pulse generation rests upon nonlinear propagation of OPA pulses in a hollow-core fiber and subsequent compression solely by linear propagation through Fused Silica which exhibits anomalous dispersion [1]. The spectral phase introduced by self-phase modulation and self-steepening cancels material dispersion up to third order to provide an ideal laser source for HHG in gases with low ionization potential.

The generation of isolated 80 attosecond laser pulses has almost reached its physical limitation when using established Ti:Sa schemes at 800 nm of the driving field [1]. Further shortening of attosecond pulse duration utilizing high harmonic generation (HHG) can be achieved by using few cycle pulses at longer wavelengths because the HHG cut-off shifts towards higher photon energies proportional to the square of the laser wavelength [2]. In this paper, we present (1) a simple and robust experimental approach to generate carrier envelope phase (CEP) stable quasi single cycle laser pulses at 1.8 µm and (2) HHG from Argon using those pulses.