Ridge Waveguide for Thermally Assisted Recording - Optimization, Scaling, and Wavelength Dependence

Here, we will present FETD modeling results which optimize peak power absorption in the disk media. We have used plane-wave illumination (which can approximate the wavefront from a laser cavity or thin-film waveguide). The aperture and slider material are assumed to be quartz. We have found globally optimized ridge waveguide designs as a function of wavelength and fly-height. For optimized structures, we do find clear resonant behavior in the near field pattern although the resulting near-field "spectra" bear little resemblance to the calculated far field transmission spectra. That is, high far-field transmission does not indicate a good design for data recording. We will also present modeling results on the effects of fly-height variation for fixed design, how dielectric overcoats influence ridge waveguide efficiency, and the effects of media thickness and the presence of a heatsink. Results for various metals will be shown.