## 3 Results and Discussion
The amplitude of the front negative pulse increases with increasing the angle of incidence, while the amplitude of the positive tail of the pulse decreases. At large angles of incidence (\(\alpha=\) 79.5\({}^{\circ}\) and 82.5\({}^{\circ}\)), the positive part of the pulse completely disappears and the photovoltage is generated in the form of a negative unipolar pulse. It should be added that when the direction of rotation of the electric field vector of the incident radiation changes (i.e., at left-hand circularly polarized laser beam) the polarities of the pulses shown in Figure 5 change to the opposite ones. Thus, the waveforms of the transverse photovoltage pulses at circular polarization strongly depend on the angle of incidence, which is not typical of the longitudinal photovoltage pulses at different polarizations (see Figure 3) and the transverse photovoltage pulses at linear polarization (see Figure 4). The unusual dependence of the waveform of the transverse photovoltage pulses on the angle of incidence at circular polarization can be explained on the basis of the interaction of linear and circular photocurrents arising in the surface layer of the film as a result of the transformation of the incident circular polarization into elliptical polarization upon the refraction of light at the air/film interface. Figure 4: The waveforms of the transverse photovoltage pulses normalized to their extreme values at linear polarization (\(\Phi=-45^{\circ}\)), recorded at positive (solid lines) and negative (dashed lines) angles of incidence \(\alpha\). The upper inset shows the dependence of the recorded pulses duration \(\tau\) on the angle of incidence. The bottom inset shows the sketch of the experimental setup. To determine the polarization of the refracted beam, one can use the complex Fresnel refractive indices \(t_{\rm p},\ t_{\rm s}\) for \(p\)- and \(s\)-polarizations, respectively, at the air/semitransparent film interface given in [66]:  
\[t_{\rm p}=\frac{2\hat{n}\cos\alpha}{\hat{n}^{2}\cos\alpha+\sqrt{\hat{n}^{2}-\sin ^{2}\alpha}},t_{\rm s}=\frac{2\cos\alpha}{\sqrt{\hat{n}^{2}-\sin^{2}\alpha}+ \cos\alpha}, \tag{5}\]  
where \(\hat{n}=n+i\kappa\) is the complex refractive index, \(n\) is the real refractive index that determines the phase velocity (\(n=1.64\)), and \(\kappa\) is the absorption coefficient (\(\kappa=2.14\)) that determines the attenuation of light in the film itself. From expression (5), the phase shift \(\delta_{\rm t}\) between the components of the refracted beam with \(p\)- and \(s\)-polarizations is determined by the formula:  
\[\eta_{\rm x}(\alpha,\Phi)=\ \eta_{\rm x}(\alpha,\Phi=0)\cos^{2}, \tag{2}\]0  
where:  
\[\eta_{\rm x}(\alpha,\Phi)=\ \eta_{\rm x}(\alpha,\Phi=0)\cos^{2}, \tag{2}\]1  
\[\eta_{\rm x}(\alpha,\Phi)=\ \eta_{\rm x}(\alpha,\Phi=0)\cos^{2}, \tag{2}\]2  
\[\eta_{\rm x}(\alpha,\Phi)=\ \eta_{\rm x}(\alpha,\Phi=0)\cos^{2}, \tag{2}\]3 The waveforms of the transverse photovoltage pulses normalized to their extreme values for circularly polarized incident radiation, recorded for different angles of incidence \(\alpha\). The inset shows the sketch of the experimental setup. \[\eta_{\rm x}(\alpha,\Phi)=\ \eta_{\rm x}(\alpha,\Phi=0)\cos^{2}, \tag{2}\]4  
\[\eta_{\rm x}(\alpha,\Phi)=\ \eta_{\rm x}(\alpha,\Phi=0)\cos^{2}, \tag{2}\]5  
\(\delta_{\rm tp}\), \(\delta_{\rm ts}\) are the phase shifts of the \(p\)- and \(s\)-beam components, respectively, resulting from refraction at the interface between two media with a complex refractive index, and \(\delta_{0}\) is the initial phase shift between the \(p\)- and \(s\)-components before refraction. For the circular polarization of the incident radiation \(\delta_{0}=\pi/2\), where the signs \"+\" and \"\(-\)\" are the opposite of the sign of circular polarization.