Temperature dependence of voltage-controlled polarization plane rotation in a magnetic and electro-optic heterostructure

We propose a theoretical study of the influence of temperature on the state of polarization of a near-infrared light beam reflected from or transmitted through a voltage-controlled nematic liquid crystal (LC) cell deposited on a magnetic film. In both cases, the change in polarization with respect to that of the incoming beam originates in the linear Kerr or Faraday effects taking place in the magnetic layer, but the overall value of the polarization plane rotation depends on the reflectivity and transmittivity of the whole heterostructure. Temperature manifests itself in all layers of the structure through both thermal expansion and the thermo-optic effect when it varies between room temperature and the temperature of nematic-isotropic phase transition in the LC. The thermo-optic effect is strongest in the LC cell, where it is shown to induce noticeable variations of the polarization plane rotation of both reflected and transmitted light beams in that temperature range. Such temperature-dependent changes of the magneto-optical response can be compensated for by adjusting the dc voltage applied to the LC. On the other hand, we show that they may be exploited for sensitive temperature monitoring.