Laser; Beams / Pens / Pointers

Laser beams (color: red, green, & blue)

A laser is a device that emits light through a process of optical amplification or in general terms, the amplification of a light signal.  Laser beams are famously employed as advanced weapon systems in science fiction flicks, but today’s actual laser weapons are still in the experimental stage. The general idea behind laser-beam weaponry is to hit a target with a short train of brief light pulses. The resulting rapid evaporation and expansion of the surface causes shockwaves that damages or destroys the target. But, the power needed to project a high-powered laser beam of this kind is beyond the limit of current modern mobile powered technology.

A laser pointer or laser pen is a small portable device which has a power source, most usually one or more AAA batteries, with a laser emitting a very narrow low-powered beam of visible light, intended to highlight something of interest with a small bright spot of colored light that is some distance away. Its power is typically restricted in most jurisdictions so as not to exceed 5 milliwatts (mW) or 5 thousandths of a watt, and yes devices such as these are available in today’s market place which display colors that include: Red, red-orange, blue, yellow, violet and green.

The small width of the beam coupled with the low power of a typical laser pointer makes the beam itself invisible when displayed in a reasonably clean atmosphere; a point of light is shown or illuminated when striking a solid surface, otherwise you wouldn’t know it was there.  However, higher-power and higher-frequency green or blue lasers may produce a beam that is visible to the unaided eye even in clean air because of the process known as “Rayleigh Scattering” (the elastic scattering of light ) of air molecules through which the beam passes, especially if viewed in moderately or dimly lit environments.  Rayleigh scattering is also demonstrated by the blue hue of the daytime sky and the reddening of the sun at sunset.

Green laser light beams appear brighter than other colors, red or blue for example, because the human eye is more sensitive at low light levels in the green region of the light spectrum which has a wavelength of 520 to 570 nanometers (one nm = 1 billionth of a meter); all visible light ranges from 400 nm to 710 nm but human sight sensitivity progressively decreases for redder and bluer wavelengths.    

      

Laser pointers are typically used as a signaling tool, even in daylight, and are able to produce a bright signal for potential search and rescue vehicles by using an inexpensive, small and lightweight device of the type that can readily be carried in an emergency kit or even a shirt pocket.  The down side is that if aimed at a person’s eyes the result may cause temporary disturbances to vision; there is limited evidence of rare though minor permanent harm, however, low-powered laser pointers (5 mW or less) are not considered to be seriously hazardous to anyone’s health.

Accurately aligned laser pointers are now often used as laser gun sights, wherein “red” marks the deadly spot; a low-powered laser is known to scare away wild animals for those confronted by such beasts during a leisurely hike in the woods or may serve as an excellent detection or locator device in the event that you find yourself on the wrong end of a hunt and rescue mission. Add to those obvious benefits the ever popular “laser” amusement shows or the curious fact that for some reason, housecats and even servals (medium sized African wild cats), are attracted to the motion of the dot produced by laser pointers.

Laser pointers have become readily available, so naturally they have been misused, which has led to the development of laws and regulations specifically addressing the use of such lasers, but the long range of the devices makes it very difficult to find the source of a laser spot. 

Currently there is legislation limiting the power output of laser pointers in some countries, but higher-power devices are presently produced in other regions like China and Hong Kong that are frequently imported by customers who purchase them directly via e-mail orders from on-line stores. The legality of such transactions are not always clear and to make matters worse, such high powered lasers are frequently sold in packaging similar to that for low-powered laser pointers.

There have been numerous villous incidents regarding such devices, in particular, those involving aircraft, and as should be the case, the authorities in many countries take them extremely serious. Many people have been convicted and sentenced, sometimes to several years’ imprisonment; in fact in the United States shining a laser pointer of any class (low / high powered) at an aircraft is illegal and punishable by a fine of up to $11,000.

It has been established that at around 200 to 300 milliwatts, the beam from a laser can be felt on the skin; at roughly 500 milliwatts, the laser’s beam begins to be a skin burn hazard, but only if the person is within a few meters or yards of the beam.  Incidentally, even powerful industrial lasers cannot cause deep burns or severed limbs; create gun-type injuries or other adverse effects as is often seen in science fiction movies. Although multi-watt laser beams are most definitely serious eye hazards, they are ineffective at causing debilitating bodily injuries.

This easily explains why laser pointer sales are restricted, but why would anyone want a laser pointer with high powered capability in the first place? Brightness of the light / beam is typically the answer. However, anything above a 50 milliwatts pointer is over shadowed by the potential hazards from the general use benefits one gains from a brighter beam / light.

Surprisingly, there is not a generally accepted definition of a laser “pointer” and there is no “maximum” power in the U.S. as is the case in many other countries. A person can buy a laser of whatever power they want, even tens of watts.  Prior to 2010, in the U.S., the FDA described pointers as “hand-held lasers that are promoted as those for pointing out objects or locations” with output power of 5 milliwatts or less. Some folks considered this to be a “loophole” by making the argument that if a hand-held laser is not promoted or advertised for pointing or amusement purposes, then it can legally be sold.

So, beginning in 2010, the FDA started classifying handheld portable lasers as “surveying, leveling and alignment” (SLA) lasers, and will be trying to further restrict sales of lasers above 5 milliwatts based on this new rules interpretation.

There apparently is no federal law against an individual owning a laser, regardless of power in the U.S.; in spite of this, some states and localities may have their own laws that do just that. Therefore, at the federal level, an “illegal laser pointer” is illegal only from the manufacturer's or seller's standpoint. An “illegal” laser may be too powerful to be sold or promoted for pointing purposes, or it may be lacking in some required safety feature(s), and that only applies to the seller or manufacturer of the product; not the individual.

Although it is sometimes argued that an individual residing in the United States is required by law to report to the federal government the ownership of any type of laser product; this is in all likely-hood a fallacy.  Otherwise that MP3 player or the CD player you have tucked away in your room which utilizes a type of laser would undoubtedly constitute guilt for most all of us. In any event, perhaps the best way to determine if you have in your possession a laser product that places you outside the law, the advice of an attorney with valid experience in the field is called for.

Sources:

http://en.wikipedia.org/wiki/Laser_pointer                                            http://laserpointersafety.com/FAQ/FAQ.html                                      http://en.wikipedia.org/wiki/Laser_cutting                                                               http://www.fda.gov/Radiation-EmittingProducts /RadiationEmittingProducts /sandProcedures/HomeBusinessandEntertainment/LaserProductsandInstruments/ucm116373.htm