Design of high-performance supersphere solid immersion lenses

Two types of novel solid immersion lens are designed and investigated theoretically using the vector diffraction theory. The advantages of these so-called high-performance supersphere solid immersion lenses (HPSILs) are that they can improve the Strehl ratio of the focused spot and increase the focal depth of near-field optical systems. Both the spot size and the sidelobe intensity are not increased, however, compared with those of the standard Weierstrass solid immersion lens. These HPSILs will be useful for near-field optical data storage and photolithography.