Optical sensing of square lattice photonic crystal point-shifted nanocavity for protein adsorption detection

摘要

We propose a point-shifted D0 nanocavity formed by locally modulating four central air holes innsquare lattice photonic crystal for optical sensing application. Three defect modes in this nanocavity,nincluding monopole, whispering-gallery, and dipole modes, are identified in experiments. We alsonapply a chemical treatment on InGaAsP surface to form a 1-octadecanethiol linking monolayer,nwhich enables the following protein adsorption. In experiments, the wavelength shifts of lasingnmodes in the D0 nanocavity due to the protein adsorption are observed and agree with the simulationnresults. This can be a practical tool for label-free molecule detection in biomedical researches.n© 2010 American Institute of Physics. u0004doi:10.1063/1.3436550