ellipsometer a birefringent in its application in the photo - elasticimetrie

摘要

P the present invention relates to an ellipsometer to the plane of the rotating / p & & p & an ellipsometer according to the present invention receives a light wave 10, the polarization states are to be studied, the incident beam passes successively through a quarter wave plate oriented it, a birefringent plate 12 which rotates at constant speed and a polarizer 14 in order to achieve a photoreceiver 15. A synchronous detection of the output signals 16 of the photodetector 15 is carried out with the aid of reference signals at frequencies 2w and 4w. The reference signal at frequency 2w is obtained at the output of a photodetector 22 receiving a light signal having in succession through a circular polarizer 21, the rotating elements 12, and the polarizer 14. The reference signal at frequency 4w is obtained at the outlet 33 of a photoreceiver 32 receiving a light signal having in succession through a polarizer 31 of the same orientation as the quarter-wave plate 11, the rotating elements 12 and the polarizer 14. A suitable electronic processing of the output signal 16 makes it possible to obtain directly the parameters α and λ of a polarized light wave by measurements of phase. / p & & p & the present invention applies in particular to the photoelasticimetry / p