Letter | Published:

A Direct Method for Determining the Index of Refraction of Thin Films

Nature volume 158, pages 703704 (16 November 1946) | Download Citation



IN working with high-frequency discharges obtained in air, at a pressure of about 1 mm., by the use of external electrodes surrounding a glass tube, an interference pattern was observed after a run of twenty hours or more. The pattern was visible both inside the tube at the edges of the electrodes and on glass strips placed under the electrodes within the tube. Patterns were obtained on clear strips of glass and on strips previously coated with thin metallic layers. Fig. 1, an enlarged photograph taken by sodium light reflected from the surface of a strip, shows a characteristic pattern which was formed on that portion of the strip immediately under one of the electrodes. The pattern appears to be similar in nature to those observed by Bochstahler and Overbeck1, Nathanson2, Nathanson and Bartberger3 and others, in sputtering discharges, and is due apparently either to the deposition of a thin layer of some transparent material, or to some action of the discharge on the surface of the glass. If we assume the first hypothesis, the maximum thickness of the deposit can be shown to be of the order of 5 wave-lengths (in the medium). Since this thickness is attained only very near the edge of the deposit, where it is a maximum, the total amount of material in a deposit must be very small and analysis by ordinary methods extremely difficult. It was thus thought advisable to obtain some clue as to the nature of the deposit by determining its index of refraction by means of what seems to be a new method.

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  1. 1.

    , and , J. Phys. Rev., 37, 465 (1931).

  2. 2.

    , Phys. Rev., 41, 373 (1932).

  3. 3.

    , and , J. Opt. Soc. Amer., 29, 417 (1939).

  4. 4.

    , Proc. Roy. Soc., A, 184, 41 (1945).

  5. 5.

    , Can. J. Res., 16, 191 (1938).

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  1. Queen's University, Kingston, Canada. Sept. 25.

    • , R. W. STEWART
    •  & J. I. LODGE


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