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Primary growth zoning and oscillatory zoning of Iceland spar from the Razlom deposit (Siberia, Russia)
Published in Vladimir Litvinenko, Innovation-Based Development of the Mineral Resources Sector: Challenges and Prospects, 2018
M.N. Logunova, J. Götze, M.A. Ivanov, G. Heide
Iceland spar is a transparent coarse-crystalline variety of calcite (trigonal CaCO3, space group 3/2 m), it is a rare and scarce type of mineral raw material. It has unique properties that determine its wide application in optics: good light transmission in the range from ultraviolet to near infrared, large birefringence and high degree of polarization of the light beam. Crystals of Iceland spar or their parts that meet the technical requirements are called optical calcite and are used in the production of polarizing prisms, laser-cutting elements, laser gates, etc. These devices are an integral part of lasers, optoelectronic and computing machines and other systems that are of paramount importance for modern technology and space exploration.
Fresnel–Arago fifth law of interference: the first description of a geometric phase in optics
Published in Journal of Modern Optics, 2021
In the second experiment, proposed by Arago, they used polarizers in combination with the slits. They took a pile of 15 thin mica plates and bisected them, so that they obtained two piles of plates of the same thickness. Then they placed a pile behind each one of the slits. The piles where oriented so that they made an angle of incident of 60. In this arrangement, the stack of plates of mica was acting as a linear polarizer since each reflection depleted the incident beam of s-polarized light, leaving a greater fraction of p-polarized light in the transmitted beam. They adjusted the orientation of the mica plates so that, in the slits, orthogonal polarizations were produced. Finally, they mounted a doubly refracting Iceland spar rhomboid behind them, acting as an analyzer, with its principal section at an angle of 45 with respect to the planes of polarization. This crystal resolved each of the two polarized beams in its ±45 components. In this case, as opposed to the previous experiment, they found no traces of interference between any of the four resulting light pencils, despite there were pairs sharing the same polarization.
Interactions between apolar, basic and acidic model oils and a calcite surface
Published in Journal of Dispersion Science and Technology, 2019
Xiaoyan Liu, Karen L. Feilberg, Wei Yan, Erling H. Stenby, Esben Thormann
Thermally oxidized silicon wafers with a 100 nm thick SiO2 layer were purchased from WaferNet, Inc., USA. Silica particles with a diameter of approximately 20 μm were purchased from Kisker Biotech, Germany. Rectangular cantilevers, CSC38/tipless/Cr-Au, purchased from MikroMasch, Germany, with the approximate dimensions of 250 μm in length and 32.5 μm in width, were used for the AFM force measurements. The spring constants of the cantilevers were determined by the Sader method.[27,28] After calibration, a silica particle was glued to the end of the cantilever with the assistance of an Eppendorf Micromanipulator (PatchMan NP 2), a Nikon Eclipse LV100ND microscope and a small amount of epoxy glue (Araldite, Rapid).The exact size of the particles was determined by using the microscope, employing image analysis with Infinity Analyzer (Lumenera Corporation). The prepared cantilevers with silica particles were cleaned using a plasma cleaner (Harrick PDC-3XG, New York) for 40 seconds. After plasma cleaning, the cantilevers with silica particles and the silica surfaces were modified by trimethoxy(octyl)silane (96%), (3-aminopropyl)trimethoxysilane (APTES, 99%), and (3-mercaptopropyl)trimethoxysilane (95%), purchased from Sigma-Aldrich, Denmark, by vapor phase silanization.[29–32] The silane based monolayers on the AFM probes and on flat silica substrates (for contact angle measurements)were prepared using a similar procedure as described in detail in our previous work.[29] Hereafter, we will refer to the modified probes as apolar, basic and acidic model oil probes, respectively. The prepared model oil probes were used for AFM force measurements immediately after preparation. A calcite crystal (Iceland spar, Ward’s science, Brazil) was cleaved from a cleaned, optical sample. The calcite crystal was rinsed with Milli-Q water, followed by blow-drying with compressed air. The sample was used for the AFM force measurements immediately after cleaning.