Self-assembled perfect absorber for laser-driven flyer

Abstract

In this work, we experimentally demonstrate a high-performance laser-driven flyer (LDF) by introducing a perfect absorber in the ablation layer to improve the energy utilization efficiency, where the perfect absorber is composed of a layer of silver nano-triangular array, a dielectric layer, and a layer of silver film. The perfect absorber was realized by the simple and low-cost colloid lithography technique, and the maximal absorbance can reach to about 95% at 1064 nm under an optimization condition. The in-depth electromagnetic simulation indicates that the perfect absorber can greatly improve the energy absorbance in the ablation layer at the beginning of laser illumination, and thus the temperature and pressure of the subsequently generated plasma. In experiment, this improved plasma was used to launch a 25 µm thick Al flyer, and the flyer velocity was measured using a photonic Doppler velocimetry. A maximum speed of about 2140 m s − 1 was achieved in experiment, which is about 1.3 times larger than that (1650 m s − 1 ) of pure Al foil flyers. The extracted transient accelerated speed indicates that the absorber improved LDF owns higher accelerated speed at the beginning 20 ns, especially for the beginning 5 ns. The striking experiment indicates that the flyers formed in the improved LDF own a larger averaged striking depth, and some flyers give a striking depth in 80 µm that is twice larger than that formed in the normal LDF. The electromagnetic properties of the perfect absorber, the transient speed of flyer, and the striking morphology have been systematically investigated.