<title>High-density phase-change optical recording using a solid immersion lens</title>

Abstract

ABSTRACT A near-field optical recording technique using a solid immersion tens (SIL) and a red semiconductor laser light source (X=65Onm) has been applied to the phase change optical recording. We have recorded and erased amorphous marks of 300 rimin diameter using a hemisphere SIL (n1 .84, designed effective NA1 .1).Keywords: Solid immersion lens, high density recording, phase change recording, near-field optics 1. INTRODUCTION The data density of the optical recording disk mainly depends on the focused beam spot size. In conventional opticalrecording systems, the minimum beam spot size, which is limited by diffraction, can be reduced by using a shorter wavelengthlight source or a larger NA objective lens. Recently, near-field optical techniques have been developed to overcome thediffraction limit. in particular, Betzig et al.' have applied a scanning near-field optical microscope (SNOM), which has atapered fiber probe with a sub-micron aperture, for the recording of magneto-optical (MO) media. However, the low opticalcoupling efficiency of this fiber probe needs further improvement for practical data storage application. In other research,