Determination of the Polarization Plane Specific Rotation in Gyrotropic Crystals of the Middle Category by the Spectrophotometric Method

• Published in: Russian microelectronics Vol. 52; no. 8; pp. 757 - 763
• Main Authors: Zabelina, E. V., Shahin, R., Kozlova, N. S., Kasimova, V. M.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.12.2023; Springer Nature B.V
• Subjects: Crystals; Electrical Engineering; Engineering; Luminous intensity; Parallel plates; Polarization; Polarizers; Prisms; Rotation; Silicon dioxide; Single crystals; Spectrophotometry; spectrophotometry; uniaxial single crystals; optical properties; optical axis; single crystals; optical anisotropy; polarization plane rotation
• ISSN: 1063-7397; 1608-3415
• DOI: 10.1134/S1063739723080103

— A large number of modern functional single crystals of the middle category belong to gyrotropic media. In these crystals, when light propagates along the optical axis, rotation of the plane of its polarization is observed. In this study a spectrophotometric method is used to obtain the dispersion dependences of the rotation angle of the polarization plane. This method is based on measuring the intensity of the light passing through the polarizer–crystal–analyzer system. The crystal is a polished plane-parallel plate of a uniaxial gyrotropic crystal cut perpendicularly to the optical axis. Measurements are carried out on a Cary-5000 UV-Vis-NIR spectrophotometer in the wavelength range of 200–1200 nm using polarizers Glan–Taylor prisms. Polished plane-parallel plates of known SiO 2 and α-LiIO 3 crystals are used as samples. The obtained dispersion dependences of the spectral transmission coefficients have an oscillating character. The discrete values of the specific angles of rotation of the plane of polarization of light are calculated from the extrema on these dependences. These discrete values can be approximated by the Drude, Chandrasekhar, and Vyshin formulas, depending on what determines the nature of the rotational ability of the plane of polarization of light in each particular material. For the studied crystals the dependences of the modified Drude formula of the form 1/ρ = f (λ 2 ), which should have a linear character in the case of an ideal crystal, are plotted. The obtained experimental results are closely correlated to the available published data. The advantages of this method lie in its efficiency, the possibility of obtaining dispersion dependences of the specific rotation angle of the polarization plane, the need for a single sample, the possibility of assessing the nature of the rotational ability of specific crystals, and the possibility of evaluating the structural perfection of the studied crystals.