Single-wavelength size focusing of ultra-intense ultrashort lasers with rotational hyperbolic mirrors

Compressing all the energy of a laser pulse into a spatiotemporal focal cube edged by the laser center wavelength will realize the highest intensity of an ultra-intense ultrashort laser, which is called the λ3 regime or the λ3 laser. Herein, we introduced a rotational hyperbolic mirror—an important rotational conic section mirror with two foci—that is used as a secondary focusing mirror after a rotational parabolic mirror to reduce the focal spot size from several wavelengths to a single wavelength by significantly increasing the focusing angular aperture. Compared with the rotational ellipsoidal mirror, the first focal spot with a high intensity, as well as some unwanted strong-field effects, is avoided. The optimal focusing condition of this method is presented and the enhanced tight focusing for a femtosecond petawatt laser and the λ3 laser is numerically simulated, which can enhance the focused intensities of ultra-intense ultrashort lasers for laser physics.