Enhancing Thermal Dissipation in Amorphous Silicon Metasurfaces via Laser-Induced Crystallization

Amorphous silicon (a-Si) metasurfaces demonstrate remarkable light manipulation capabilities owing to their high refractive index and low loss characteristics. However, the low thermal conductance intrinsic to a-Si leads to substantial heat accumulation during beam modulation, which may cause thermal damage and limit the permissible intensity of the incident beam. Here, laser-induced crystallization to improve the thermal transport properties of the a-Si-based metasurface is proposed. Raman spectroscopy analysis identifies the crystallization thresholds of a-Si at 1.10 × 10 5 and 9.78 × 10 4 W/cm 2 , corresponding to laser spot radii of 1.30 and 0.54 μm, respectively. The maximum temperature rise in the crystallized silicon metasurface is 52% lower than that in the a-Si one under the identical incident power intensity. Furthermore, the crystallized polycrystalline silicon metasurface still maintains excellent optical response with high transmission and 2π phase control. These findings provide an effective strategy for augmenting heat dissipation in amorphous metasurface systems, potentially extending their utility at high laser fluence.