A sensing method and apparatus using photonic band gap multilayered
material. Photonic band gap multi-layers are formed from alternating
layers of higher refractive index and lower refractive index materials,
and may be deposited or disposed on a optically transparent substrate or
a reflecting face of a prism. Light is directed into the prism, directed
to the photonic band gap multilayer, and reflected out of the prism,
where it is captured and analyzed. Various sensor configurations keep
light wavelength or coupling angle fixed, while monitoring the change in
the other parameter. Also disclosed is a microarray configuration with an
array of probe spots placed on one surface of the multilayer, which is
mounted on an x-y translation stage.