Planar photonic crystals have been used as the basis of many biological sensing devices. Here, we successfully demonstrated that the combination of a photonic crystal structure and a dielectric nanorod coating prepared by the glancing angle deposition technique can lead to significant increases in the device sensitivity. By incorporating a high refractive index dielectric nanorod coating onto label-free photonic crystal biosensor structures, the surface area of the device is increased. Results for detection of polymer films, proteins, and small molecules indicate up to a seven-fold enhancement of detected adsorbed mass density. When a nanorod coating is applied on top of the high index layer of an enhanced fluorescence photonic crystal biosensor, the emission intensity of a fluorescent dye on the device is increased by over one hundred times compared to a reference glass slide. Photonic crystal surfaces have also been combined with a SiO2â��Ag â��post-capâ�� nanostructure for applications in surface-enhanced Raman spectroscopy (SERS). It has recently been demonstrated that the resonant near fields of the photonic crystal can be used to efficiently couple light from a laser to isolated Ag nanoparticles to achieve a high SERS enhancement factor.
1000 MNTL, University of Illinois, Urbana-Champaign, IL