## 2 Materials and Methods  
The developed solution is based on the nematic liquid crystal (NLC) cell in a twisted nematic (TN) [37; 38] configuration placed between two crossed polarizers, as schematically shown in Figure 1c. A layer of NLC exhibits the so-called twisted nematic texture due to mechanical unidirectional rubbing of the NLC cell substrates, which are coated with a thin ZLI 2650 (Mecrk, Darmstadt, Germany) polyimide layer. We used the standard rubbing process to create the right conditions for anchoring the NLC molecules inside the NLC cells. First, we applied an alignment polyimide layer onto glass substrates using a spin-coating technique. Then, we preheated the substrates at 100 \({}^{\circ}\)C on a hot plate for 15 min to remove the solvent, followed by baking them in an oven at 230 \({}^{\circ}\)C for 2 h. After that, we rubbed the substrates using a rubbing machine we designed and manufactured in-house. The machine had a 30 mm diameter roller covered with a rubbing cloth, rotating at 400 rpm. The rubbed substrates were moved under the roller at a constant speed of 100 mm/min. For the manual cell assembly, we used a photocurable NOA68 adhesive and glass spacers (microspheres or microrods) that were sprayed over one of the substrate surfaces prior to assembly. The density of spacer deposition was approximately a few pieces per square millimeter. The final thickness of the cells was verified by interferometric technique (in the case of thin cells) or by direct gap measurement under the simple optical imaging system (CCD camera combined with a microscope objective). The orientation director of one substrate is turned by 90\({}^{\circ}\) compared to another substrate, causing a 90\({}^{\circ}\) twist in the alignment of liquid crystal (LC) molecules--as schematically sketched in Figure 1d. The LC cell with the TN LC is positioned between two polarizers that are perpendicular to each other. The first polarizer is aligned with the long axis of the molecules on the adjacent glass plate. Once the incident light passes through the polarizer, it enters the LC layer and aligns its polarization according to the twisted molecular orientation of LCs, resulting in a 90\({}^{\circ}\) rotation towards the orthogonal direction. At the exit plane of the LC cell, the polarization of the incident light becomes parallel to the analyzer's transmission axis, allowing the maximum amount of light to pass through the device. In traditional electro-optical systems, light transmission is typically controlled by an applied field across the cell electrodes using the electrically controlled birefringence effect. This effect essentially reorients the director axis to align the liquid crystals (LCs) perpendicular to the glass substrates, causing the transmission to decrease significantly when viewed through crossed polarizers. In an all-optical switching system designed for potential smart CCD protection, the incident intensity would self-attenuate through the reorientation of the director axis or the induced disorder in the order parameter. At low intensities, full transmission is possible, but higher laser intensity would be blocked or attenuated due to the laser-induced untwist of the NLC director axis or the changes of the order parameter, thus inhibiting the polarization rotation process. This means that the output's light polarisation would no longer match the second polarizer. The result would be a sharp decrease in transmission at the output. As a light source, we used a Millenia Spectra-Physics continuous-wave (CW) laser with continuously adjustable power from 0 to 3.5 W, a wavelength of \(\lambda\) = 532 nm, and a beam diameter of about 2 mm. The choice of green light was based on data showing that green lasers, compared to other wavelengths, cause the most substantial interference in the visual field, significantly impacting visual perception and leading to distraction and transient visual effects [1; 46; 47].