Stabilized porous silicon optical superlattices with controlled surface passivation

We report on very effective stabilization of porous silicon optical devices through a chemical surface modification technique. Such a chemical treatment proves to alter the growth of native silicon oxide on pore surfaces and thus prevents the optical device from chemical aging. As an example, we apply this technique to one-dimensional freestanding optical superlattices made of five coupled microcavities. We demonstrate how the transmission resonances of the superlattice stabilize after treatment, which implies that refractive indices in the multilayer structure remain constant. The effectiveness of the chemical surface modification technique guarantees a long-life functionality of porous silicon-based optical devices.