The given beam of elliptically polarized light traverses a phase compensator plate and rotating analyzer and enters a photoelectric cell suitably connected to an amplifier circuit and detecting device. The azimuth γ, of the polarizer producing the elliptically polarized light, and ϕ, that of the planes of polarization of the compensator (or the azimuth ϕ, and α, the phase difference introduced by the compensator) are adjusted until the detector (headphones) shows no modulation of the cell current. Tan γ, the ratio of the components of the elliptically polarized light, and Δ, the phase difference between them, can be calculated from the formulae; cos 2γ=±sin α sin 2ϕ and cot Δ=tan α cos 2ϕ. The method has been tested in the visible spectrum through a wide range of intensities. The sensitivity increases with the light flux in the cell and is practically independent of stray light. An accuracy of 1 part in 4000 or 5000 or less than 1 minute of arc in azimuthal readings is easily obtained. Polaroid plates can be used instead of Nicol prisms with no serious loss in sensitivity.
© 1937 Optical Society of AmericaFull Article | PDF Article