Measurement of the phase shift upon reflection from photonic crystals

The phase dependence of light reflected from colloidal photonic crystals is measured using a large resonant cavity and self-assembled colloidal photonic crystals. We measure the expected phase shift upon reflection from the photonic crystal, which varies from 0 to 180 deg across the photonic crystal stop band. These measurements are then fed directly into the design of photonic crystal cavities. We obtain a measure for the precision needed in the fabrication of photonic crystal resonant cavities.