## 3 Results
### Repeatability, Field of View, and Climate Tests  
In order to thoroughly assess the repeatability, reliability, and stability of the suggested optical power limiter for optoelectronic devices (e.g., photodetectors and/or digital cameras), a set of 24 nematic liquid crystal (NLC) cells with a twisted nematic (TN) configuration and internal plastic polarizers arranged in a crossed alignment were prepared. Each cell had a uniform thickness of 12 \(\upmu\)m. Measurements were performed for 6 CHBT NLC doped with 1% SBII \(w/w\). The results depicted in Figure 5a exhibit high reproducibility in optical performance. Transmittance measurements performed on the entire series show excellent repeatability, with the mean transmittance value (below the threshold power) at the level of 54% with a notably low standard deviation of under 2% throughout a power range of 0 to 200 mW. These results confirm the device's consistency and emphasize the effectiveness of the proposed NLC TN configuration in providing reliable protection across various samples. To determine the effectiveness of the proposed optical power limiter, it is important to test its ability to function well at various angles of the laser beam. We conducted tests to evaluate the angular tolerance of the device by measuring light transmittance at different angles of incidence. This helped us determine the sensitivity of the device to the angle of incidence of the laser beam. The main results obtained and the definition of the angle of incidence (AOI) of the beam are shown in Figure 5b. The successive data sets correspond to the AOI of \(\alpha\) = 0\({}^{\circ}\), \(\alpha\) = 10\({}^{\circ}\), \(\alpha\) = 20\({}^{\circ}\), \(\alpha\) = 25\({}^{\circ}\), and \(\alpha\) = 30\({}^{\circ}\), yellow to green markers in Figure 5b, respectively. In this experiment, a liquid crystal cell was analyzed by exposing it to a light beam at different angles of incidence (AOIs). The beam was first directed at a normal incidence angle, represented by \(\alpha\) = 0\({}^{\circ}\), and the average transmittance for the beam power below the threshold value was approximately 55%. This study showed that the threshold power levels remained constant across all angles tested, confirming the device's stable performance. However, we noted some variations in the transmission coefficient: it remained within 45% to 55% for AOIs between 0\({}^{\circ}\) and 20\({}^{\circ}\), then decreased to approximately 35% at an AOI of 30\({}^{\circ}\). Nevertheless, the results of this study demonstrate the device's ability to maintain optimal performance under various operational conditions, a critical factor for its usefulness in situations where laser beams may not always be directed at a perpendicular angle. \begin{table}
\begin{tabular}{c c c} \hline
**Cell Thickness** & **P\({}_{\text{in}}\) = 100 mW** & **P\({}_{\text{in}}\) = 200 mW** \\ \hline
12 \(\upmu\)m & T\({}_{1}\) = 18 ms; T\({}_{2}\) = 410 ms & T\({}_{1}\) = 12 ms; T\({}_{2}\) = 300 ms \\
30 \(\upmu\)m & T\({}_{1}\) = 19 ms; T\({}_{2}\) = 335 ms & T\({}_{1}\) = 15 ms; T\({}_{2}\) = 320 ms \\ \hline \end{tabular}
\end{table} 
Table 1: Response times of nematic liquid crystals optical power limiters with integrated foil film polarizers (NLC: 6 CHBT doped with 1% \(w/w\) of SBII dye). In order to investigate how high temperature affects the NLC power limiter's performance, we placed the NLC cell (which included foil polarizers and 6 CHBT NLC + 1% SBII \(w/w\)) in a climate chamber with simulated environmental conditions for one hour. The temperature was increased to +70 \({}^{\circ}\)C, while the humidity was maintained at 50%. After completing the cycle, the sample was removed from the climate chamber and tested for its transmittance characteristics (Figure 5c). In the same way, we also tested the effect of a low temperature (\(-5\)\({}^{\circ}\)C) and high and low humidity (10% and 80%, at room temperature), and the obtained results were close to the one presented in Figure 5c (for a high temperature).