High-Q cavities in photosensitive photonic crystals

We propose a novel concept for creating high-Q cavities in photonic crystal slabs (PCSs) composed of photosensitive material. To date, high-Q cavities have been realized through the use of double heterostructures where the lattice geometry is altered via nanolithography. Here, we show that selective postexposure to light of a uniform PCS composed of photosensitive material, altering the refractive index permanently, can also yield high-Q microcavities. We show theoretically that high-Q cavities (up to Q = 1 x 10(6)) can be achieved with photoinduced index changes that are well within what can be achieved in chalcogenide glasses.