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Liquid crystals can help divert the laser pointer attacks on the aircraft



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Liquid crystals can help divert the laser pointer attacks on the aircraft

The liquid crystals interspersed between two-inch squares of glass disperse green and blue light on a wall when the cells are activated by a laser illumination (right panels). Credit: Daniel Maurer

Going to a laser beam on an airplane is not a harmless joke: the sudden glow of bright light can disable the pilot, risking the lives of passengers and the crew. But since attacks can occur with lasers of different colors, such as red, green, or blue, scientists have had difficulty developing a single method to prevent all lengths of laser light. Today, researchers describe liquid crystals that could someday be incorporated into the aircraft screens to block any bright and focused light color.


The researchers will present their results today at the National Meeting and Exhibition of the Chemical Society of the United States (ACS).

According to the Federal Aviation Administration, in 2017 6,754 laser strikes were reported on the aircraft. "We have collaborated in the aviation department of our university on the growing problem that happens in airports around the world, where people shot lasers on boarding planes during takeoff and landing, the critical phases of the flight" says Jason Keleher, PhD in Investigation, the main researcher of the project. These attacks, which cause bright lightning in the cabin, may distract the pilots or inflict temporary or permanent visual damage, depending on the wavelength and the intensity of the laser.

"We wanted to propose a solution that does not require us to completely engineer the windshield of an aircraft, but adds a layer to the glass that takes advantage of the existing electrical system for defrosting the windshield," says Daniel Maurer, a undergraduate student. Keleher and Maurer are at the University of Lewis.

Instead of joining the windshield, previous approaches have included windshields or drop-down glasses that pilots give during take-off and landing. However, these may be uncomfortable, as they require the flight crew to take these precautions if they are really targeted or not. An even bigger problem is that these strategies only work for specific wavelengths of laser light. "Do not block everything," says Maurer. "Normally they are directed to green lasers because they are used for most attacks."

To develop their new approach, the researchers took advantage of liquid crystals: materials with properties between liquids and solid crystals that make them useful on electronic screens. The team placed a solution of liquid crystals called N– (4-methoxybenzylidene) -4-butylaniline (MBBA) between two 1-inch square crystals. MBBA has a transparent liquid phase and an opaque crystalline phase that disperses light. Through the application of a voltage to the device, the researchers made the crystals align with the electric field and move to a phase change towards the crystal state More solid.

The lined crystals blocked up to 95 percent of the red, blue and green beams, by means of a combination of dispersion of light, absorption of the energy of the laser and cross polarization. The liquid crystals could block the lasers of different powers, simulating different distances of lighting, as well as the light glowed in different angles on the glass.

Additionally, the system was fully automatic: a photo camera detected laser light and then triggered the power supply system to apply the voltage. When the beam was removed, the system turned off the feed and the liquid crystals returned to its transparent liquid state. "We just want to block the point where the laser is hitting the windshield and then returning it quickly to normal after the laser has been switched off," Keleher says. The rest of the windshield, which was not affected by the laser, would remain transparent at all times.

Now that the researchers have shown that their approach works, they plan to scale it from squares of one inch to the size of an entire aircraft screens. The initial results have shown that a pattern of the 2-inch glass square sensor sensors will respond only to the illuminated glass section. The team is also testing different types of liquid crystals to find them even more efficient and versatile that return to the transparent state more quickly once the laser has been removed.


New phenomenon discovered that solves a common problem in the lasers: division of the wavelength


More information:
Analyzing the molecular structure of liquid crystals to develop independent wavelength films to mitigate aircraft laser attacks, the American Chemical Society (ACS) Spring 2019 National Meeting & Exposition.

Provided by
American Chemical Society

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Liquid crystals can help deviate laser pointer attacks on aircraft (2019, March 31)
recovered on March 31, 2019
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