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Unraveling the “Switching” Mechanism of Liquid Crystals for Laser Mitigation to Advance Aviation Safety

Tuesday, 15 May 2018
Ballroom 6ABC (Washington State Convention Center)
D. Santefort (Lewis University, Department of Phsyics), S. A. Smyth (Lewis University), J. Hofmann (Lewis University, Department of Phsyics), C. D. Crowder (Lewis University, Department of Physics), and J. J. Keleher (Lewis University, Department of Chemistry)
Laser light illuminations threatened the commercial and private aviation industry for the last decade, with attacks having doubled over the past five years. Furthermore, the intensity of the incoming laser light can distract, or even flash blind, pilots during critical phases of flight. To decrease the intensity of incoming laser light, the liquid crystal (LC) N-(4-Methoxybenzylidene)-4-butylaniline was deposited between two pieces of conductive Indium Tin Oxide coated glass. Data have shown that the test cell is capable of decreasing up to 80% 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. This research proposes that the test cell uses a mechanism which reduces the intensity of laser light by increasing the spread of the light, making the cell look opaque. To further investigate this mechanism, the cells were analyzed using polarization microscopy, which allowed for the pseudo-crystalline regions of the liquid crystals to be observed. The constant formation and motion of these regions result in dynamic light scattering within the cell due to the LC’s orientation-dependent index of refraction. This mechanism will be used to further increase the mitigation of laser light and the responsiveness of the LCs to an applied voltage.