Advantage of a disposable focusing lens in petawatt laser for inertial confinement fusion

Abstract

The inertial confinement fusion laser facility usually has several hundred large-aperture laser beams. A focusing off-axis parabolic (OAP) mirror combined with a debris shield to focus the petawatt lasers must be placed outside the target chamber for target space limitation. Further increasing the focusing power density of ps-petawatt lasers for large F-number focusing is difficult. However, a disposable lens with a smaller F-number that is used to simultaneously replace the parabolic mirror and debris shield can be placed inside the chamber by an extension pipe. The lens only needs a small target space and can increase the focusing power density of the petawatt laser over 35 times more than an OAP mirror under a 20° solid angle. The nonlinear effect of self-phase modulation may decrease the quality of the spot distribution, but under the correction of a deformable mirror with νcutoff = 0.0625 mm−1, a better focusing spot distribution can be obtained.