NEAR-FIELD OPTICAL-DATA STORAGE USING A SOLID IMMERSION LENS

A near-field optical technique, using a new type of solid immersion le ns (SIL), has been developed and applied to the writing and reading of domains in magneto-optic material. The SIL is a truncated glass spher e which serves to increase the numerical aperture of the optical syste m by n2, where n is the index of refraction of the lens material. Usin g a SIL made from n = 1.83 glass and illuminating with 780 nm light, w e have achieved a 317 nm spot size. We have resolved a 500 nm period g rating, and written and read 350 nm diameter magnetic domains. The tec hnique should be capable of a 125 nm focused spot size using blue ligh t.