Absorbed laser energy appears in the target material as heat. Absorption and transmission are functions of the chemical and physical characteristics of the target material and the wavelength of the incident radiation. At visible wavelengths laser radiation impinging on the eye is focused on the retina and , if sufficient energy is absorbed, can cause cell destruction. At longer and shorter wavelengths, such as the far infrared and the ultraviolet, radiation striking the eye is absorbed in the cornea and the lens rather than being focused on the retina. Although these structures are less easily damaged than the retina, excessive energy absorption can cause cell damage and impairment of vision.
Reflection is primarily a function of the physical character of the surface of the target material.
A reflector such as a flat mirror changes the direction of an incident beam with little or no absorption. A curved mirror or surface will change the divergence angle of the impinging laser beam as well as its direction. For a diffuse reflection, the reflected energy is scattered in all directions thereby reducing the energy or power density. Generally, diffusely reflecting surfaces are favored when designing a laser experiment since their use reduces the likelihood of a specular reflection and hence enhances the safety of the experiment. Policy It is the policy of UMR to protect personnel and property from harmful exposure to laser radiation.