Self-healing effects in the fabrication process of photonic crystals

We demonstrate a self-healing effect of unwanted defects in the autocloning process: autocloning is a previously proposed technique to fabricate multidimensional periodic nanostructures by stacking up corrugated multilayers. With the self-healing effect, aperiodic perturbations in the initial periodic shape of the structure immediately disappear and the surface shape becomes periodic in a few cycles of stacking. If the perturbations exist in photonic crystal, they cause light-scattering loss and also make the boundaries between photonic bands and band gaps unclear. In other words, they make the attenuation of light at the frequency in photonic band gaps weak. Consequently, to attain uniformity of the shape automatically with this effect is very important in the fabrication process for practical photonic crystal devices. In this letter, we verify this phenomenon experimentally, and discuss the mechanism by comparison with process simulation.