Multi-wavelength enhancement of silicon Raman scattering by nanoscale laser surface ablation

In this paper, we produce nanoholes on a silicon surface by laser ablation. Those nanoholes lead to a yield enhancement of light-matter interaction. Performing Raman spectroscopy on silicon, an enhancement of its main Raman mode is observed: it is twice higher with the nanoholes compared to a flat surface. Such a feature appears whatever the excitation wavelength (488, 514.5 and 632.8 nm) and the laser power, revealing a broad band light-matter interaction enhancement. In addition, no change in the position and shape of the main Raman mode of silicon is observed, suggesting that no structural damages are induced by laser ablation. These results clearly demonstrate the potentiality of such nanostructures for the further development of silicon photonics.