A combination of a diffraction grating and a mirror integrates a hollow waveguide and a photonic-bandgap structure into a compact optical element, offering a simple new structure for various applications in nonlinear and ultrafast optics. The main features of transmission spectra observed in experiments performed with such waveguide structures are qualitatively interpreted in terms of the coupled-mode theory. Localization of light near the surface of a metal-coated grating in lowest-order TM modes in the created waveguide enhances effects related to the photonic-bandgap structure. 2002 Optical Society of America.
