Optics.org April 2, 2019
Researchers at Lewis University, Illinois, focused on the polarization and absorbance properties of liquid crystal materials to block incoming laser light. To decrease the intensity of incoming laser light, the liquid crystal N-(4-Methoxybenzylidene)-4-butylaniline was deposited between two pieces of conductive indium tin oxide-coated glass. The test cell can decrease up to 80 percent of incoming laser light by transitioning from its transparent, liquid phase to its opaque, pseudo-crystalline phase, with the cell being able to return to its transparent phase in less than three seconds. The phase change is controlled by an electric current applied to the liquid crystal layer, causing a realignment of the molecules for as long as the current is flowing. In trials using small one-inch squares of material, the aligned crystals blocked red, blue and green laser beams, through a combination of light scattering, absorption of the laser’s energy and cross-polarization, successfully blocked lasers of different powers, simulating various distances of illumination and light shone at different angles onto the glass. They are working to block the spot where the laser is hitting the windshield and then have it quickly go back to normal after the laser is gone. The rest of the windshield, which was not hit by the laser, would always remain transparent…read more.
Pilot protection: liquid crystals block laser light. Credit: The article