Riki Matsuda

A retinal scanning display with a wavefront curvature modulator

A retinal scanning display with a wavefront curvature modulator (WCM) has been developed and demonstrated. The WCM dynamically modulates the divergence of laser beams to produce multiple focal planes in synchronization with 2-D laser scanning. The produced images have given real stereoscopic feelings to observers because two focal planes are created in a frame. In addition, a motion parallax has been also observed. It has greatly emphasized stereoscopic effects.

RF Magnetron-Sputtered Si-Rich SiO2 Films on GdTbFe

Si-rich SiO2 films have been produced by magnetron sputtering using a composite target. The magneto-optical properties in GdTbFe were successfully improved by using Si-rich SiO2 as a protective layer. In order to characterize the Si-rich SiO2 films and the interface in a Si-rich SiO2/GdTbFe structure, X-ray photoelectron spectroscopy (XPS) and Auger depth profiling were employed. Any excess Si in Si-rich SiO2 plays an important role in the improvement of the magneto-optical properties. It was revealed that Si-rich SiO2 comprised three components: elemental Si, SiO2 and SiO-like suboxide. The chemical shift of Si2p form the SiO2 component was measured with values of 3.25 eV. Auger and XPS measurements revealed that FeSi2 was formed at the interface. The FeSi2 layer works as a blocking layer against oxygen penetration.

High-Track-Density Flattened Magnetooptical Disks with Low Crosstalk

The carrier-to-noise ratio (CNR), crosstalk and noise levels have been investigated for flattened and semiflattened magnetooptical disks with narrow track pitches of 1.2 and 1.0 µm. The track pitch of the flattened and semiflattened disks can be reduced to less than the laser spot size under the condition that the laser spots irradiated on the adjacent recording regions overlap each other only on the spiral guiding band. The CNR of 48.3 dB and low crosstalk of less than -36 dB were achieved for the track pitch of 1.2 µm when the domains of 0.76 µm length were recorded. Crosstalk of less than -30 dB was obtained for the track pitch of 1.0 µm with the conventional optical head having an objective lens of 0.53 NA and a 780-nm laser.