DIVERGENCE

摘要

It is not just the power of a laser that will dictate how it behaves; the collimation plays a significant role as well. Collimated light is light whose rays are parallel and show little divergence over distance; light from a laser is therefore highly collimated. When looking at the safety implications of a laser beam one important parameter to consider is the amount of power in the beam divided by the cross-sectional area of the beam. This parameter is referred to as the irradiance of the beam and is measured in watts per square metre or Wm-2.