  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 mm 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 ~ 30 mW laser powers. Over this tuning range, the cavity Q
decreases from 3.2\times10^5 to 1.2\times10^5. Numerical simulations model the
temperature distributions in the silicon photonic crystal membrane and the
cavity resonance shift from oxidation.
