Dresden 2017 – wissenschaftliches Programm
CPP 18.3: Poster
Montag, 20. März 2017, 18:30–21:00, P1C
Optical contrast factor measurements of ternary mixtures with a multi-wavelength Michelson interferometer — •Marcel Schraml and Werner Köhler — Physikalisches Institut, Universität Bayreuth, 95440 Bayreuth, Germany
Non-isothermal diffusion in ternary mixtures is extensively studied both on ground and under microgravity conditions on the Internation Space Station ISS (ESA/Roscosmos, DCMIX3). In most cases are optical, contactless techniques the method of choice. These methods have the disadvantage that the measured data need to be transformed from the refraction index space into the concentration space. Therefor the contrast factor matrix aij = ( ∂ ni / ∂ cj)p,T,ck≠ j has to be inverted. At least two different wavelengths are necessary to provide sufficient information for ternray mixtures. We have designed a multi-wavelength Michelson-Interferometer to get precise refraction index values over the whole spectral range measured simultaneously with the same specimen. The Michelson interferometer uses optical fibers to couple the four lasers (406nm, 543 nm, 632 nm, 934 nm) into the experimental setup. The number of wavelengths can easily be extended. The geometrical path is varied and the optical path is measured. At the moment there is no commercial setup available. On the poster we will discuss the present state of the instrument, its design and the achievable accuracy.