Selective tuning of high-Q silicon photonic crystal nanocavities via laser-assisted local oxidation

We examine the cavity resonance tuning of high-Q silicon photonic crystal heterostructures by localized laser-assisted thermal oxidation using a 532 nm continuous wave laser focused to a 2.5 mu m radius spot-size. The total shift is consistent with the parabolic rate law. A tuning range of up to 8.7 nm is achieved with similar to 30 mW laser powers. Over this tuning range, the cavity Qs decreases from 3.2x10(5) to 1.2x10(5). Numerical simulations model the temperature distributions in the silicon photonic crystal membrane and the cavity resonance shift from oxidation. (C) 2011 Optical Society of America