Applications of high-field lasers in x-ray imaging and ultrafast plasma nonlinear optics

At the high-field laser facility of National Central University intense electromagnetic radiation of 1020 W/cm2 can be produced at the focus of a 100-TW laser pulse. Such an intense electromagnetic radiation is utilized for the development of tabletop particle accelerators and ultrafast plasma nonlinear optics in extreme-UV/soft x-ray and mid-infrared. Schemes of electron and proton acceleration are being explored by utilizing the tremendous longitudinal quasi-static electric field produced by engineered laser-plasma interaction. Interaction between accelerated electrons, transient plasma structures, high-Z ions, and intense laser pulses has opened new playgrounds for ultrafast extreme-UV and mid-IR plasma nonlinear optics and hard x-ray/gamma ray generation. Space-time structure and evolution of laser wakefield is resolved for the first time by probing it synchronously with 2-fs accelerated electron pulses. High resolution phase-contrast x-ray imaging is achieved by utilizing the high spatial coherence x-ray produced from betatron oscillation in the laser wavefield. Sub-terawatt tunable mid-infrared pulses is produced for the first time by photon deceleration in the laser wakefield.