Blue-Laser Readout Properties of Super Resolution Near Field Structure Disc with Inorganic Write-Once Recording Layer

Abstract

A novel inorganic write-once recording material SbNx (antimony nitride) was proposed for super resolution near field structure (super-RENS) discs. The layer structure is polycarbonate substrate (0.6 mm)/ZnS–SiO2 (170 nm)/AgOx (15 nm)/ZnS–SiO2 (40 nm)/SbNx (25 nm)/Ag (100 nm)/UV-curing resin/dummy PC substrate (0.6 mm). The recording layer with high-contrast characteristics enhanced the readout signal, which was compared with that of conventional phase-change materials. The carrier-to-noise ratio (CNR) of 150 nm mark length was about 44.2 dB at a readout power of 2.5 mW using blue laser. A below-diffraction-limited mark length as short as 60 nm can be readout using blue laser of 405 nm with a lens having a numerical aperture of 0.65.