The problem of strong laser light directed against airplanes exists throughout the world, but is most prevalent in USA. In Sweden, more than 20 cases have been reported and these have primarily occurred during approaches to Bromma and Arlanda. In Malmö, a 19-year-old man has now been charged with having attacked a police helicopter by directing green laser light against it. Some of the attacks on Swedish planes may have been accomplished using legal laser pointers with strengths of up to 5 milliwatts. However, it is not difficult obtain stronger laser pointers – it is possible to buy laser bulbs that are several hundred milliwatts over the Internet.

"Laser light blinds pilots, making it very difficult for them to land the aircraft. So far, there haven't been any accidents. But overseas, it has been necessary to terminate some landings and there have even been cases where pilots have suffered eye injuries," says Cesar Lopes, lead researcher in the FOI laser protection project called, "Skydd mot laser".

For some time now, FOI, on assignment by the Swedish Armed Forces, has been working with laser protection for sensors – the human eye is also a type of sensor – and at present, FOI is a leader in this area. FOI has also been monitoring the trend of mischievous use of lasers and the problem of using lasers to blind pilots. In 2005, FOI organized a workshop on these issues with participants from the Swedish Civil Aviation Authority, the Swedish Civil Aviation Administration (LFV), and the Swedish Airline Pilots Association (SPF). Now, FOI researchers are working on protection that is based on LC technology, which can be activated to block laser light during an attack.

"The filter, which is transparent, blocks the wavelength range that is sent out by the laser, but is still able to let in other wavelengths, so that pilots are able to continue the flight without becoming blinded," says Cesar Lopes.
However, a finished product that can by used by airlines is still several years away.

"The difficulty lies in achieving an optimal mixture of liquid crystals in the LC screen, such that the laser's wavelengths are significantly filtered, without affecting other wavelengths so much that visibility becomes impaired. Also, it is necessary for the protective shield to activate quickly ¬¬– which means as little as a thousandth of a second – in order to avoid eye damage," says Cesar Lopes.