A word of caution: DANGEROUS PRODUCTSClass3B lasers are not considered pointers often used for fun, amusement and entertainment such as the lower power Class 3A. Class3B lasers emitting over 50 milliwatts can burn objects and possibly cause fires when used at close range. Lasers over 100 milliwatts are especially dangerous in this respect. Never point in the direction of people or animals as these devices can cause blindness and burn skin!
Laser Beam Visibility Information
Laser pointers are battery powered hand held visible laser light sources capable of projecting a narrow beam of light over considerable distances. There are three views of interest, the first is the view of the user where one sees the beam traversing to the impact point. This view shows the actual ray and the impact point appearing as a bright dot on the target. The actual visibility of the ray will vary depending on the color, power, moisture and dust content in the air. Range can be miles depending on the absorption of the medium. Note that the brighter the ray, the less power at the impact point. This is why on a foggy night the ray can be strikingly visible but the impact point will be of limited range.
The second view of interest is from the target point. This is where when looking towards the source the laser appears as the brightest object on the horizon and on a clear night can be visible to a distance limited only by the curvature of the earth! If one were to compute the color temperature of a omnidirectional monochromatic source necessary to produce this effect would quickly find astronomical temperature values to millions of degrees!
The third view is from the side where visibility will vary as the angle varies from the impact position. Minimum brightness being at right angles to the ray. Again as in the first view absorption plays a significant part where heavy moist and dusty air will enhance this viewing angle.
A major factor in visibility is the acuity of the human eye. You will note the above optical curve as shown where the visibility factor is the “y” axis plotted against the laser color wave length being the “x” axis. You immediately see that the green is far brighter than the red or blue to the human eye with yellow close behind. This graph explains why a greeen laser of 532 nm compared to an equal powered red laser of 650 nm is 10 times brighter to the human eye. You can use the graph to find the relative powers of any visible laser in question.
Note: The color green is the most perceptible color to the human eye. Green lasers now appear as ultra bright light sources when compared to other colors of equal power. As an example a 5 mw green laser will appear many times brighter than a 5 mw red laser. A 5 mw green laser beam (ray) will be visible in low light where a red laser is only visible as the impact point on the target. A great advantage is that you get this brightness without exceeding the 5 mw Class3a compliance regulation as required by the FDA.
Classification of Power Output for all Lasers
CLASS 3AEmits a power level of between 2 and < 5 milliwatts (.005 watt). This may seem minuscule but when contained in a narrow beam can be very optically impressive being able to illuminate an object over several miles under dry clear conditions. Observer visibility can be limited by the curvature of the earth!! These lasers operate from a push button and require labelling as shown. Laser pointers fall into this category.
CLASS 3BLaser systems emit a power level of between >5 and < 500 milliwatts (.5 watt). This power level can produce some real neat optical effects and is often used for star pointing. The ray of the laser is usually quite visible dependent on power level and color. Output powers over 50 milliwatts can burn objects and human flesh. These lasers require a key switch with non removable key in the “on” position, emission indicator lamp, remote control access port and an aperture shutter.
CLASS 4Laser systems emit a power level of between >500 milliwatts (.5 watt) and upwards. These power levels can burn, cut and fabricate most materials including metals. These higher powered laser systems are the candidates for directed energy beam weapons. Class4 lasers require a key switch with non removable key in the “on” position, emission indicator lamp, remote control access port, time delay and an aperture shutter.
Hand Held Laser Pointers All Colors CLASS 3A Power Levels
Laser pointers are battery powered hand held visible laser light sources with maximum power outputs of 5 milliwatts capable of projecting a narrow beam of light over considerable distances. These devices are intended for fun and amusement purposes and are not that particularly dangerous. They are great for playing with cats, attracting attention, highlighting, pointing, alignment.
Portable Laser Systems All Colors CLASS 3B Power Levels
Portable battery powered Class3B lasers products with power outputs over 5 milliwatts are not intended for directing towards people or animals. They are not considered to be laser pointers often used for fun and amusement devices. Class3B lasers pose a severe eye hazard and can burn skin.
Laser pointers with power outputs over 50 milliwatts can melt plastic. Lasers over 100 milliwatts can cause materials to actually burn. These lasers are intended to allow the researcher or serious experimenter the option of portable field use with built in power and complete portability. They are not intended to be pointed in the direction of people as at these power levels, serious eye and skin damage can occur.