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Papas Fritas writes:
"Scott Smith reports at AP that 26-year-old Sergio Patrick Rodriguez has been convicted of pointing a green laser at a Fresno Police Department helicopter and sentenced to spend 14 years in federal prison. 'This is not a game. It is dangerous, and it is a felony,' says US Attorney Benjamin B. Wagner. 'Those who aim lasers at aircraft should know that we will seek to convict them, and we will seek to send them to prison. The safety of aircraft and the people in them demands no less.' According to evidence presented at trial, Rodriguez and his girlfriend, Jennifer Lorraine Coleman, 23, used a high-powered green laser pointer 13 times more powerful than common pointers to repeatedly strike the cockpit of Air 1 during a clear summer night in 2012. In imposing the sentence, Judge O'Neill considered not only the severity of the offenses but Rodriguez's criminal history, numerous probation violations, and Bulldog gang affiliation. An expert said that the laser pointer that Rodriguez used was an instrument capable of inflicting serious bodily injury and death due to a high potential for crash caused by visual interference. A jury found Rodriguez guilty of attempting to interfere with safe operation of aircraft and aiming a laser pointer at an aircraft. 'Lasing aircraft is not a joke or a casual prank,' says Special Agent in Charge Monica M. Miller of the FBI's Sacramento field office. 'Rodriguez's sentence clearly demonstrates the seriousness of his actions and that the FBI will work with its law enforcement partners to locate and arrest those who engage in dangerous, improper use of hand-held lasers that puts us all at risk.'
On February 11, 2014, in 12 cities, the FBI, in collaboration with the Air Line Pilots Association International and the FAA, announced the Laser Threat Awareness campaign, a nationwide effort to alert the public to the threat that aircraft laser illumination poses and the penalties for such activity. The FBI will offer up to $10,000 for information leading to the arrest of any individual who intentionally aims a laser at an aircraft. The program is being rolled out in Albuquerque, New Mexico; Houston and San Antonio, Texas; Los Angeles and Sacramento, California; Philadelphia; Phoenix, Arizona; Cleveland, Ohio; Washington, D.C.; Chicago; New York; and San Juan, Puerto Rico."
(Score: 3, Informative) by Foobar Bazbot on Tuesday March 11 2014, @05:28PM
This isn't the only (or even the main) spreading effect involved -- the beam itself diverges significantly over such such ranges, so the beam from a very high-powered pointer at long range may have much lower power density than an alread "safe" <5mW pointer at short range. Typical divergence values for laser pointers are on the order of 1 milliradian, so over a range of 1 km, the beam expands to 1m. Compared to a perhaps 5mm beam at short ranges, that's 200^2= 40000x the area, so even a full 1W laser has 1/40th the power density of a 1mW laser at short range. There's essentially no risk of eye damage from anything that can reasonably be called a laser pointer at these ranges. You need more power and/or a larger aperture to have sufficient power density to be a credible direct* hazard.
But that part's wrong, because as above, the beam is pretty big at typical airplane ranges, so you've got a decent chance of momentarily catching the pilots eyes with some part of your big, low-density, beam, and probably making him blink.
* This is not to deny the existence of indirect hazards, such as the possibility that dazzling/momentarily blinding the pilot (or even just inducing a reflexive blink) could, under the right circumstances, cause him to crash the plane, just as high-beams could, in just the right circumstances, cause a driver to crash a car. I'm just talking about the direct hazard of eye damage.
(Score: 2) by Foobar Bazbot on Tuesday March 11 2014, @05:44PM
I realized after posting, from other comments, that this case involved a police chopper, not an airliner. In light of that, the 1km distance for which I ran numbers may not be typical. Still, the point stands, and anyone may easily do the math for any range they deem representative...
(Score: 2) by hubie on Tuesday March 11 2014, @08:07PM
You also have to take into consideration that the eye is about 50 times more sensitive in the green than it is in the red, which is why I generally hate when a speaker uses a green laser pointer during a presentation because they appear to be much brighter (in fact, depending upon the laser pointer they use and the properties of the wall/screen, I will look away from where they are pointing because it is discomforting to stare at the laser spot). Also, an idealized nice, clean cockpit window may act as a weakly powered optic to spread out the light some more, but a real cockpit window has all sorts of scratches, microbubbles, etc. in them that will cause all sorts of annoying glinting.