Improving the recording ability of a near-field optical storage system by higher-order radially polarized beams

Distributions of the optical field in a solid immersion lens recording system are calculated for higher-order radially polarized modes of the incidence. Results show that two higher-order radially polarized modes of R-TEM11* and R-TEM21* are useful to near-field optical recording, but further higher-order modes such as R-TEM31*, R-TEM41*, and R-TEM51* are not useful due to the strong side-lobe intensity. Compared with R-TEM01* beam focusing, the full width at half-maximum of the recording spot is decreased markedly and the focal depth is increased substantially by using R-TEM11* beam focusing. The effect of the beam width of the R-TEM11* mode is also discussed. (C) 2009 Optical Society of America