Pre-Compensation Design and Verification of Flexure-Backed Support for Transport Mirrors

In inertial confinement fusion (ICF) facilities, the surface figure of large-aperture optical elements directly affects the transmission quality and pointing accuracy of high-power laser beams. As a key component in the target area, the transport mirror redirects the parallel laser beams from the amplifiers into radial incidence onto the target sphere. It must maintain both stability and surface figure control under extreme conditions such as large self-weight deformation, inclined installation, and array configurations. This work proposes a gravity pre-compensation design based on a flexure-backed support. A pre-compensation structure is designed according to the deformation characteristics of remote-center flexure mechanisms, and an integrated opto-mechanical simulation framework is established for parameter optimization. Simulations show that, at a 45° inclined posture, the additional peak-to-valley (PV) deformation of the transport mirror is about 130 nm, while the discrepancies between prototype testing and simulations in terms of PV and Grms remain within 3%. This study provides a feasible approach for surface figure control and optimization of large-aperture optical elements.