Research progress in fabrication technology of polymer-based perturbation targets

An accurate evaluation of the growth rate of the Rayleigh-Taylor (R-T) instability is a critical issue for inertial confinement fusion (ICF). By means of the face-on radiography technology, perturbation targets are usually adopted to investigate the Rayleigh-Taylor instability in ICF resolved experiments. This paper provides a comprehensive review of recent advances in the fabrication technology of polymer-based perturbation targets, which are essential experimental targets for studying hydrodynamic instabilities in ICF. The review systematically covers three major aspects: target design configurations, polymer material systems, and fabrication methodologies. For target design, both single-layer planar targets and dual-layer composite targets (film-foam structures) are discussed in terms of their structural characteristics and physical experiment requirements. Regarding material systems, the properties and preparation methods of two dominant polymers, namely polystyrene (PS) and poly(4-methyl-1-pentene) (PMP) foam, are elaborated, including doped PS films and ultra-low-density PMP porous materials. With respect to fabrication techniques, conventional methods such as laser interference process, single-point diamond turning (SPDT) and femtosecond laser machining are compared, and emerging additive manufacturing technologies represented by two-photon polymerization 3D printing are highlighted for their unique advantages in fabricating complex configurations such as composite planar and spherical targets. Furthermore, the key technical bottlenecks currently limiting target performance, including fabrication accuracy and consistency as well as interface quality control in film-foam composites, are analyzed. Finally, future research directions for high-precision, complex-configuration perturbation targets are proposed to meet the demands of next-generation ICF experiments.