Different Class of Lasers

Different Class of Lasers

Are lasers dangerous?

As mentioned, lasers can be very bright! High power lasers can burn skin and ignite clothing. Fortunately, laser pointers are medium power so they cannot burn skin or ignite clothing. Medium and high power lasers can damage your eyes before you can blink, therefore, the beam from a laser pointer should never be pointed at anyone at any time.

Lasers are classified by the radiant power and wavelength of the light they emit.

Class 1 Laser. A Class 1 laser is considered to be incapable of producing dangerous radiation levels and is therefore exempt from most control measures or other forms of surveillance.

Class 2 Laser (Low Power). A Class 2 laser emits visible radiation (400-700 nm). Eye protection is afforded by the normal human aversion response to bright radiant sources. This type of laser may present some danger if viewed directly for periods exceeding the 0.25 second aversion time. The "Class 2a" classification was developed for supermarket bar-code scanners; Class 2a lasers are not intended for viewing but are not hazardous if viewed for up to 1000 seconds. Class 2 does not apply to lasers radiating at wavelengths less than 400 nm or greater than 700 nm.

Class 3 Laser (Medium Power). A Class 3 laser is hazardous under direct beam and specular- reflection viewing conditions, but the diffuse reflection is usually not a hazard. A Class 3 laser is normally not a fire hazard. Ultraviolet (UV) and infrared (IR) lasers that emit invisible beams (<400 nm and >700 nm) are always Class 1, Class 3 or Class 4. Class 3 lasers are divided into two subclasses, 3a and 3b, each having slightly different control requirements.

Class 4 Laser (High Power). The direct beam, specular reflection and diffuse reflection from a Class 4 laser are hazardous to the eye and skin. A Class 4 laser can be a fire hazard.

When laser pointers were first introduced, they were normally class 2. During the last few years, the power of laser pointers has increased so that they are now typically class 3a. These have the potential to damage the eyes.