Nanometer-Sized Phase-Change Recording Using a Scanning Near-Field Optical Microscope with a Laser Diode

Abstract

We present for the first time a nanometer-sized phase-change recording using a scanning near-field optical microscope (PC-SNOM recording). The recording experiments were performed with a SNOM using a 785-nm-wavelength semiconductor laser diode, shear force detection for gap control and reflected light detection for observing the domains (reading). The recording media of ZnS·SiO2(20 nm)/GeSbTe(30 nm)/ZnS·SiO2(150 nm)/polycarbonate substrate were used. The writings were done at laser powers of 8.4–7.3 mW in the probe for pulse widths of 5 or 0.5 ms. As a result, we obtained a minimum recorded domain size of 60 nm in diameter. This size shows a potential to achieve an ultrahigh density PC-SNOM recording with about 170 Gb/in2. A possibility of achieving high speed readout for the future data storage is also discussed.

Sub-wavelength grid patterns on silicon surface by pulsed CO 2 laser irradiation

“…As reported in our earlier paper [4], the morphology of the periodic structures on silicon irradiated by a pulsed CO2 laser depends on the incident laser energy. The structures formed at lower laser energies near the threshold consists of a relatively flat profile of two annular regions of fringes parallel to the laser polarization direction, such as that of Fig.…”

“…Our previous paper [4] reported on periodic microstructures with parallel and circular fringes on the top surface of silicon substrates which were coated with a thin layer of paints or Au at the bottom to promote optical absorption.…”

Influence of pulse duration on the amorphization of GeSb thin films under ultrashort laser pulses

“…1 Current trends in the development of this technology include the use of short wavelength laser systems, 2 multilevel recording, 3 or nearfield concepts 4,5 in order to increase the storage density. Along with these, the optimization of recording materials for achieving increased recording speeds and data transfer rates is a topic of great interest.…”

Multi-Functional Probe Recording: Field-Induced Recording and Near-Field Optical Readout

“…However, contact problems such as tip instability, bit erasure caused by damage to the tip, or degradation of the media, still remain in realizing reliable and practical data storage using local probe technology [1]- [3]. Near-field scanning optical microscopy (NSOM) appears to be an alternative technology because sub-100-nm bits can be optically recorded and read in a non-contact mode [4], [5]. However, due to the low-light throughput of an NSOM probe and the resultant low-data recording rate, it is still far from being practically used.…”