The frequency of a laser depends on the type of material that is stimulated. The properties of lasers are similar to those of the other members of the electromagnetic spectrum. However, lasers can achieve great power densities which, along with operating at a single wavelength, has made them indispensable in today's marketplace. Lasers can also present a serious danger to the eyes and skin. Care must be taken to assure the safe operation of lasers.
Federal regulations require that all laser products.
The Standards created by the FDA divide laser products into four separate classes, based on the biological effect produced by the laser and the intensity of the radiation in the laser beam. Class I lasers produce radiation that causes no biological damage. The continuous output of Class I laser is not more the 0.39 m W. 2. Class II lasers produce radiation that can cause eye damage if exposures are direct and prolonged. Such laser devices can emit a power that exceeds the appropriate P exempt for the classification duration, but not exceeding P exempt for a 0.25-second exposure.