Demonstration of enhanced Raman scattering in high-Q silicon nanocavities operating below the silicon band-gap wavelength

We experimentally determined the quality factor (Q) and the intensity of the Raman scattered light for different silicon photonic-crystal nanocavities operating at wavelengths shorter than the silicon band-gap wavelength. Despite the relatively large absorption of silicon in this wavelength region, we observed Q values greater than 10,000 for cavities with a resonance wavelength of 1.05 mu m, and Q values greater than 30,000 for cavities with a resonance wavelength of 1.10 mu m. Additionally, we measured the Raman scattering spectra of cavities with resonance wavelengths of 1.10 mu m and 1.21 mu m. On average, the generation efficiency of the Raman scattered light in a 1.10-mu m nanocavity is 6.5 times higher than that in a 1.21-mu m nanocavity. These findings suggest that silicon nanocavities operating below the silicon band-gap wavelength could be useful in the development of silicon-based light sources.

Editors' Pick in Optics Express