Thermoelectric PbTe thin film for superresolution optical data storage

Abstract

To find its practical use in ultrahigh density optical data storage, superresolution (SR) technique needs a material that can render a high SR capability at no cost of durability against repeated readout and write. Thermoelectric materials appear to be promising candidates due to their capability of yielding phase-change-free thermo-optic changes. A feasibility study was carried out with PbTe for its large thermoelectric coefficient and high stability over a wide temperature range as a crystalline single phase. Under exposure to pulsed red light, the material was found to display positive, yet completely reversible changes of optical transmittance regardless of laser power, fulfilling basic requirements for SR readout and write. The material was also shown to have a high endurance against repeated static laser heating of up to 10(6)-10(7) cycles tested. A read only memory disk with a PbTe SR layer led to the carrier to noise ratio value of 47 dB at 3.5 mW for 0.25 mum pit; below the optical resolution limit (similar to0.27 mum) of the tester. (C) 2004 American Institute of Physics.