A semiconducting thermooptic material for potential application to super-resolution 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 read/write. Thermoelectric materials are proposed as candidates capable of yielding solid state SR effects in the absence of phase changes that are detrimental to durability. As a prototype material, PbTe is selected due to a large thermoelectric Seebeck coefficient and a high stability of a crystalline single phase state up to its melting temperature of 924 °C. A preliminary study of Pb 51Te 49 thin films was carried out with the following findings: Firstly, under exposure to pulsed light, completely reversible changes in transmittance take place regardless of power. Secondly, light transmittance grows with increasing laser power and this is not due to melting except at relatively high powers. By way of optical calculations using the measured reflectance and transmittance values combined with thermal calculations, a temperature variation of effective optical constants ( n, k) was also estimated to find that both of them decrease with increasing temperature.