Strategies for employing surface plasmons in near-field optical readout systems

The enhanced transmission of light through subwavelength-size holes in a metal plate is well-known to be associated with surface plasmons. We have undertaken a systematic theoretical study of several strategies for applying these plasmon effects in a near-field optical readout system using an exact Green's tensor formulation. Based on the results of our simulations with light of wavelength lambda = 500 nm, data structures separated by 120 nm could be clearly resolved, and asymmetries of about +/-10 nm in the optical readout system could be tolerated without serious degradation of the performance. Advantages and disadvantages of each strategy are discussed.