Oxford Centre for High Energy Density Science (OxCHEDS)

Abstract:

A high harmonic optical generator comprising a laser arrangement for emitting a beam of polarized radiation at a fundamental frequency and an optical waveguide having a hollow core for a gaseous harmonic generation medium for the generation of high harmonics of the fundamental frequency, the optical waveguide having an optical propagation axis along the hollow core, the laser arrangement is configured to couple the beam of polarized radiation along the propagation axis of the hollow core optical waveguide to provide a beam of optical driving radiation for the high harmonic generation, the optical driving radiation having a plane of polarization that rotates about the propagation axis.

Abstract:

A scheme for quasi-phase-matching high-harmonic generation is proposed in which polarization beating within a hollow core birefringent waveguide modulates the generation of harmonics. The evolution of the polarization of a laser pulse propagating in a birefringent waveguide is calculated and is shown to periodically modulate the harmonic generation process. The optimum conditions for achieving quasi-phase-matching using this scheme are explored and the growth of the harmonic intensity as a function of experimental parameters is investigated.

Abstract:

A high harmonic optical generator comprising a laser arrangement and an optical waveguide, wherein the laser arrangement is configured to couple a beam of linearly polarized radiation at a fundamental frequency into the optical waveguide to provide a beam of optical driving radiation that propagates along a propagation axis of the optical waveguide, the optical waveguide has a hollow core for a gaseous harmonic generation medium for generation of high harmonics of the fundamental frequency, and the generator is configured for the driving radiation to have a polarization ellipticity that periodically varies along the propagation axis of the optical waveguide.