The improved scheme of data recording process on an optical disc based on a substrate made of high-stable materials has been proposed. Information layer with depth of 115nm and width of 600nm has been obtained on sapphire substrate by ion-beam etching using improved scheme. These experimental results allow to create the sapphire optical discs for long-term data storage.
The non-homogeneous multilayer medium was proposed for laser thermal recording. The mathematical model of laser thermal recording based on the phase transition of non-homogeneous medium (such as melting, ablation, evaporation) to simulate and optimize was developed. It was shown that in multilayer recording medium can be performed narrower structures than in monolayer films on similar conditions. It was shown that for getting small structures the thermoconduction of recording medium should be much smaller than the thermoconduction of substrate on which a medium is deposited. It was demonstrated that in the case of strong light absorption in recording layer its thermal conductivity must be sufficiently large to ensure the transfer of heat on a distance that equals to the thickness of the layer during a time interval equals to the difference in time for warming up to the phase transition temperature of the central part of the light spots and area that separated from a center of light spot on a distance equals to the thickness of layer.
KEYWORDS: Interferometers, Semiconductor lasers, Semiconductors, Signal processing, Temperature metrology, Michelson interferometers, Digital signal processing, Distance measurement, Helium neon lasers, Algorithm development
The possibility of using semiconductor laser interferometers to measure displacements at the nanometer scale was demonstrated. The creation principles of miniature digital Michelson interferometers based on semiconductor lasers were proposed. The advanced processing algorithm for the interferometer quadrature signals was designed. It enabled to reduce restrictions on speed of measured movements. A miniature semiconductor digital Michelson interferometer was developed. Designing of the precision temperature stability system for miniature low-cost semiconductor laser with 0.01ºС accuracy enabled to use it for creation of compact interferometer rather than a helium-neon one. Proper firmware and software was designed for the interferometer signals real-time processing and conversion in to respective shifts. In the result the relative displacement between 0-500 mm was measured with a resolution of better than 1 nm. Advantages and disadvantages of practical use of the compact semiconductor digital interferometer in seismometers for the measurement of shifts were shown.
The method of high-density data recording by laser thermo-lithography with ion-beam etching was proposed. The
nanocomposite films were created by the spin-coating method on basis of organic positive photoresist and added
synthesized dyes characterized by absorption in the spectral region 390-410 nm and which are able to be evaporated by
405 nm laser radiation. The pits with 250 – 300 nm width were performed on the thin organic nanocomposite films by
405 nm laser beam focused by 0.85 NA lens. The organic nanocomposite film with obtained pits was used as a mask for
reactive ion-beam etching of glass substrate. The 150 nm pits were performed on the substrate surface in the result of the
laser thermo-lithography with ion-beam etching.
Optical discs are widely used for storage of archival data represented in a digital form. Long-term storage of information
recorded on standard CDs is provided by periodical rewriting (once in 3-5 years) on the new carriers. High-stable lightsensitive
materials and special reflective metal coatings are proposed to use for increasing the information storage terms
of the optical discs. The conducted researches have showed that the application of vitreous chalcogenide semiconductors
in optical WORM discs assures the data storage terms up to 30 years. Substantially larger terms of data storage can be
realized on the optical ROM carriers. Attainment of the guaranteed data storage terms within several hundreds years is
provided in such carriers by applying high-stable materials substrates and information should be represented in the form
of a micro-relief structure on the substrate surface. Sapphire, quartz, silicon, glass-ceramics and other materials can be
utilized for manufacturing substrates of optical BD discs (and other subsequent high-density disc formats). These materials
allow creating substrates characterized with increased melting temperature, chemical and mechanical resistance.
Furthermore, using the mentioned materials for substrates production permits applying high temperature materials, such
as chrome and nickel, to creation of high-stable refractive layers and demonstrating the sufficient mechanical adhesion
between the refractive layer and the substrate. Modern methods of thermo-lithography offers creating of nano-size images
on photo-resist layer deposited on the substrates. Those images can be transformed to the nano-size relief structures
on the surface of the high-stable materials substrates by techniques of reactive ion-beam etching.
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