Pulse–read on erasable thermal phase-change superresolution disks

Abstract

New erasable thermal phase-change superresolution (EPSR) disks composed of mask and recording layers can increase recording density by the detection of the below-diffraction-limited marks within the readout spot. The formation of the aperture and the readout signal on the EPSR disk were analyzed. The feasibility of optically designed EPSR disks was evaluated by thermal simulation. A carrier-to-noise ratio of 32 dB at a mark size of 0.4 mum, 8 dB higher than that of a conventional disk, was obtained by application of a pulse-read method to the EPSR disks at a wavelength of 780 nm and a numerical aperture of 0.55.

Readout Power Dependence of Signal Distribution Observed in Fourier Plane of Focus Spot

“…This thermal effect in our super-resolution method is similar to that in conventional super-resolution methods, such as magnetically-induced super-resolution (MSR) and phase-change super-resolution (PSR) methods. [11][12][13][14] In particular, the disk structures of PSR and super-RENS superficially resemble each other. Therefore we simulated the signal property in the Fourier plane depending on the PSRs of the front-aperture-detection (FAD) and rear-aperturedetection (RAD) models.…”

Mask Films for Thermally Induced Superresolution Readout in Rewritable Phase-Change Optical Disks

“…Recently, the superresolution technique has been successfully demonstrated in several types of optical disks, such as magnetically induced superresolution (MSR), 1) premastered optical disk by superresolution (PSR), 2) super-resolution near-field structure (Super-RENS) 3,4) and thermally induced superresolution rewritable optical disks. 5,6) However, superresolution techniques in nonmagnetic media have a particularly critical problem: readout cycle is limited.…”