Light propagation in a resonantly absorbing waveguide array

Photonic crystal enhancement of Raman scattering

Thin films of photonic crystals with inverse opal structure were prepared from opal-type templates by photocurable resin polymerization, and methylene blue dye was embedded into them as an analyte. Raman spectra were recorded at different angles of light incidence for samples with different positions of the stop band. A pure effect of the photonic stop band on the amplitude of spontaneous Raman scattering peaks for inverse opal samples without metallic nanoparticles was established for the first time. A great enhancement of the Raman spectra due to the coincidence of the stop band center with the laser wavelength was shown; the enhancement factor was estimated to be more than 50.

Diffractive properties of imaginary-part photonic crystal slab

The diffraction spectra of Imaginary-Part Photonic Crystal (IPPC) slabs are analyzed by using Scattering-Matrix Method. By investigating the thickness dependence of the diffraction, we find the remarkable red shift of central wavelength of diffraction spectrum, which obviously distinguishes from the phenomenon of spectral hole. We observe that diffraction efficiency can be enhanced more than twentyfold by optimizing the geometry parameters. These imply that the diffraction spectra of the IPPC slab can be controlled at will and used to guide the design to achieve useful nanoscale devices.