To push the generation of isolated attosecond pulses towards shorter XUV wavelengths (0.3 to 1 keV), intense few-cycle driving pulses are required whose center frequency is significantly red shifted compared to established Ti-Sa technology. A simple route for generating these pulses is demonstrated using an optical parametric amplifier (OPA). Its infrared (IR) multi-cycle laser pulses with millijoule of energy are spectrally broadened by nonlinear propagation in a hollow-core fiber (HCF) filled with Argon. For the OPA Signal wavelength (\u3bb = 1.4 micron), chirped mirrors were used for dispersion compensation with a resulting pulse duration of 13.1 fs. For the OPA Idler wavelength at 1.8 micron, a new compression scheme has been developed with which 11.2 fs laser pulses have been characterized (1 cycle= 6 fs). Here, pulse compression is achieved through the combined effects of self-steepening during nonlinear propagation in the HCF followed by anomalous dispersion during linear propagation in fused silica.Peer reviewed: YesNRC publication: Ye
