## 3 Results and Discussion
It follows from Equation (5) that the amplitude values of the complex transmission coefficients \(t_{\rm p}\) and \(t_{\rm s}\) can be determined using:  
\[\eta_{\rm x}(\alpha,\Phi)=\ \eta_{\rm x}(\alpha,\Phi=0)\cos^{2}, \tag{2}\]6  
\[\eta_{\rm x}(\alpha,\Phi)=\ \eta_{\rm x}(\alpha,\Phi=0)\cos^{2}, \tag{2}\]7  
The amplitudes of the \(p\)- and \(s\)-components of the electric field vector of the refracted beam \(\mathbf{E}^{(t)}\) describing the ellipse in the x\"y coordinate system can be found using the equations:  
\[\eta_{\rm x}(\alpha,\Phi)=\ \eta_{\rm x}(\alpha,\Phi=0)\cos^{2}, \tag{2}\]8  
respectively, where x\"y is the coordinate plane perpendicular to the wave vector \(\mathbf{k_{\rm t}}\) of the refracted beam, axis x\" is in the plane of incidence \(\sigma\), and the axis y is perpendicular to \(\sigma\). In this case, the equation of the polarization ellipse in the refracted beam depending on the ratio of the \(p\)- and \(s\)-components of the vector \(\mathbf{E}^{(t)}\) and the phase shift \(\delta_{t}\) can be written as follows:  
\[\eta_{\rm x}(\alpha,\Phi)=\ \eta_{\rm x}(\alpha,\Phi=0)\cos^{2}, \tag{2}\]9  
The polarization ellipses are characterized by the angle \(\psi\) between the semi-major axis \(a\) of the ellipse and the x\" axis lying in the incidence plane \(\sigma\) of radiation on the film (see Figure 6a,b right insets), as well as the degree of circular polarization \(P_{\rm dir}=\gamma 2 ab/\left(a^{2}+b^{2}\right)\) and degree of linear polarization \(P_{\rm lin}=\left(a^{2}-b^{2}\right)/\left(a^{2}+b^{2}\right)\), where \(b\) is the semi-minor axis of the ellipse, \(\gamma\) is the sign of circular polarization, and \(\gamma=1\) and \(\gamma=-1\) denote the rotation of the electric field vector to the right and to the left, respectively. Expression (14) makes it possible to calculate the angle \(\psi\), as well as the length of the minor \(b\) and major \(a\) semiaxes of the refracted beam polarization ellipse using the following Equations:  
Figure 1:0  
Figure 1:1  
Figure 1:2  
Equations (16) and (17) were used to calculate \(P_{\rm dir}\) and \(P_{\rm lin}\). Figure 6a,b shows the calculated values of \(\psi\), \(P_{\rm dir}\), and \(P_{\rm lin}\) for different angles \(\alpha\), for which the waveforms of the photovoltage pulses were recorded for circular and linear polarizations (\(\Phi=-45^{\circ}\)) of the incident radiation, respectively. It can be seen that when the incident beam is circularly polarized at large angles \(\alpha\), there is a significant change in the parameters \(\psi\), \(P_{\rm dir}\), and \(P_{\rm lin}\) characterizing the polarization ellipse in the refracted beam. However, at \(\alpha<20^{\circ}\), the refracted beam remains virtually circularly polarized, i.e., at small angles of incidence, the polarizations of the incident and refracted beamsvirtually coincide. It should be added that at all \(\alpha\), the signs of the circular polarization of the incident and refracted beams coincide, i.e., for both beams \(\gamma=1\). It follows from Figure 6b that with linear polarization of the incident light at \(\Phi=-45^{\circ}\) the refracted beam is also elliptically polarized, but in this case \(\gamma=-1\) (see upper inset). In addition, when changing \(\alpha\) in the range of 0-85\({}^{\circ}\), the modulus \(P_{\rm cir}\) of the refracted beam changes insignificantly from 0 to 0.32. At small angles \(\alpha\), the changes in the polarization state of the refracted beam are minimal. It is known that the transverse photocurrent \(j_{y}\) for elliptical excitation beam polarization consists of a CPC (\(j_{y,{\rm cir}}\) ) and an LPC (\(j_{y,{\rm lin}}\) ), i.e., \(j_{y}=j_{y,{\rm cir}}+j_{y,{\rm lin}}\).