Year: 1950
Type: article
Abstract: The design and operation of an interferometer of the Michelson type at a wavelength of 12.5 mm. is discussed. The required frequency stabilization of the 12.5 mm. source is achieved by using a high Q cavity as an R.F. discriminator. Wavelength measurements have been made with various spacings of the interferometer, the measured wavelength increasing as the spacing is reduced. Results indicate that the interferometer gives more accurate measurements of the wavelength when operated well in the Fraunhofer region of diffraction. The operating frequency has been measured using a calibrated frequency meter, and hence the velocity of electromagnetic waves deduced. The value obtained for this velocity agrees, within the accuracy attempted with the present instrument, viz. one part in 10 4 , with the generally accepted value for this velocity. The possibilities of increasing the accuracy of its determination with the interferometer are discussed. Measurements of the dielectric constants of low-loss materials by means of the interferometer have been made. Results obtained using ordinary commercial sheets of materials agree within a few per cent with values obtained otherwise. The use of the interferometer as a substandard of length is also discussed.
Author: W Culshaw
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2055410399