Near-Field Radiation from a Ridge Waveguide Transducer in the Vicinity of a Solid Immersion Lens

A near-field optical system is investigated to improve the transmission efficiency of near-field transducers. A ridge waveguide is placed adjacent to a solid immersion lens (SIL) but separated by a low-index dielectric layer. The incident electric field near the focus of the SIL is determined by the Richards-Wolf vector field equations. The finite element method is used to solve Maxwell's equations. A spot size of 31 nm is obtained. The maximum value of the absorbed optical power density in the recording medium is $7.51\times {10}^{-4}\mathrm{m}\mathrm{W}/{\mathrm{n}\mathrm{m}}^3$ for a 100 mW input power.