A ridge waveguide having a recessed ridge forming an isolated tip at a
terminal end of the waveguide's aperture efficiently couples light into a
spot adjacent to the tip in a medium below the terminal end of the
waveguide which is significantly smaller than the light's wavelength. The
waveguide is used to heat a recording medium via the small spot for heat
assisted recording or to pattern substrates by photolithography with line
width exposures that are significantly smaller than the wavelength of
light. The body of the waveguide may also be recessed away from the
medium in an area surrounding the waveguide's aperture to further confine
the energy emerging from the waveguide to the small spot adjacent the tip
in the medium.