A method and apparatus for installing seals in an interference fit with a comating sealing surface by initially stretching the seal installed in a groove to reduce its cross-sectional thickness perpendicular to a comating sealing surface. A preferred embodiment comprises a cathode, an anode, and one or more links formed between the cathode and the anode. The contact layer has a stacked structure formed by alternately stacking a plurality of nitride semiconductor layers having a wider bandgap and a plurality of nitride semiconductor layers having a narrower bandgap. A sample value is determined which corresponds to the obtained intermediate bit sequence. Thus, it is possible to prepare 2 or 3 dimensional colloidal photonic crystals of large scale with no defects in less time.