High-harmonic generation (HHG) traditionally combines ~100 near-infrared laser photons to generate bright, phase-matched, extreme ultraviolet beams when the emission from many atoms adds constructively. Here, we show that by guiding a mid-infrared femtosecond laser in a high-pressure gas, ultrahigh harmonics can be generated, up to orders greater than 5000,… (More)
Circularly-polarized extreme ultraviolet and X-ray radiation is useful for analysing the structural, electronic and magnetic properties of materials. To date, such radiation has only been available at large-scale X-ray facilities such as synchrotrons. Here, we demonstrate the first bright, phase-matched, extreme ultraviolet circularly-polarized high… (More)
By driving the high harmonic generation process with multi-cycle mid-infrared laser pulses, we demonstrate bright isolated, attosecond soft X-ray pulses for the first time.
High-harmonic generation is a universal response of matter to strong femtosecond laser fields, coherently upconverting light to much shorter wavelengths. Optimizing the conversion of laser light into soft x-rays typically demands a trade-off between two competing factors. Because of reduced quantum diffusion of the radiating electron wave function, the… (More)
We demonstrate bright coherent X-ray supercontinua generated through fully phase-matched upconversion of mid-IR laser light into the keV spectral region. The ultrabroad bandwidths can support pulse durations of few attoseconds, scalable to zeptosecond time scales.
We model soft x-ray high harmonic generation and propagation driven by mid-infrared lasers. We find that multi-cycle laser pulses are ideal for generating shorter bright isolated attosecond pulses via time-gated phase-matching in high-density extended media.
We demonstrate the first bright circularly-polarized high-order harmonics. Using this new tabletop light source, we demonstrate magnetic circular dichroism measurements at the M-shell absorption edges of Cobalt.
We present a new regime of UV-driven high harmonic generation, where the larger refractive index of ions counterbalances the plasma dispersion. Bright harmonic emission from ions is observed for the first time that extends up to 280 eV.
PPMgSLT is used for mode-locking of a diode-pumped Nd:GdVO<inf>4</inf> laser by intracavity SHG. Stable and self-starting operation is observed achieving output powers of up to 4.7 W and pulse durations as short as 3.2 ps.