The paper describes an interference refractometer for liquids and gases which operates automatically and reads out in digital or analog form. A compensating technique using white light is used for measurement. Zero adjustment is achieved by rotating the compensator and capturing the zero-order white light fringe by photoelectric means. Measurement of the path difference compensated by the compensator is based on electronic interpolation and counting of interference fringes by optointerferometric means, a time division multiplex technique with pulse amplitude modulation being used to obtain the electrical fringe signals.
© 1968 Optical Society of America
Original Manuscript: July 11, 1967
Published: February 1, 1968
W. Kinder, J. Neumann, H. Plesse, and R. Torge, "Automatic Interferometer with Digital Readout for Refractometric Analysis," Appl. Opt. 7, 341-342 (1968)