Medical Definition of Immersion medium
1.
In microscopy the medium used to immerse the specimen, the space between the objective lens and coverslip, or the condenser lens front element and the slide. For the latter purposes, cedar or synthetic oils with refractive indices and dispersions approximating the front elements of the lens are used for homogeneous immersion. Homogeneous immersion provides high numerical aperture, less light loss and depolarisation, and generally improved correction of aberrations. Glycerol or water may be used for immersion of particular lenses, but for high-numerical aperture lenses designed to be used with a variety of immersion media, proper adjustment of the correction collars is necessary, the refractive index, thickness, and dispersion of the immersion media and coverslips all enter into the corrections for aberrations of high-numerical aperture objective and condenser lenses.
(05 Aug 1998)
Lexicographical Neighbors of Immersion Medium
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