Effects of Aperture Wall on the Readout Signal of Erasable Thermal Phase Change Super Resolution (EPSR) Disks

Abstract

A "below-diffraction-limited" aperture within the readout spot for high-density recording can be achieved on erasable thermal phase change super resolution (EPSR) disks. Compared to the large aperture wall formed by the DC detection method, the small aperture wall formed by pulse readout can not only increase the signal amplitude, but also suppress readout noise when detecting the EPSR disks. The small aperture wall width generated by pulse readout in the EPSR disk resulted in an 8 dB higher in carrier-to-noise (CNR) than that by DC readout in the conventional single-recording-layer phase change disk when reading the below-diffraction-limited marks of 0.4 µm.

High-Temperature Complex Refractive Index of Phase Change Recording Medium of Ge2Sb2Te5 Determined Using Phase Change Static Tester and Spectroscopic Ellipsometer

“…Until now, the complex refractive index of the GST at hightemperature has been measured and analyzed mainly by in situ ellipsometry. 3,4) However, the conventional in situ ellipsometry has limits in determining the high-temperature optical constants of the GST because of the following reasons. Firstly, when the GST sandwiched by different protective materials is heated, it shows a different behaviour.…”

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.…”