The phase contrast method has initiated much work in microscopy, and outside this field we have applied it in the design of a differential refractometer for gases and liquids. This instrument has undergone modifications during the last few years and is now applicable for registration of streaming liquids and measurements of stationary fluids (E. Djurle). With the electronics operating as a null indicator the analysis of heavy water in ordinary water is made possible within 0.001%. For phase gradients within a cell containing liquids the phase contrast method presents some difficulties; an ideal solution is the birefringence interferometer proposed by Jamin but in the shape now advised by Françon. It is shown how this method is applied for accurate registration of a gradient by means of an electronic null method, and for the specific information required for obtaining diffusion constants with extremely simple methods. An isotropic compensator for microscopy has been introduced (L. Johansson), by means of which measurements are made on biological specimens rapidly and accurately that the accuracy by a color-matching method based on this compensator comes out to plus or minus 10 A (L. Johansson-B. Afzelius).
© 1957 Optical Society of AmericaFull Article | PDF Article
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