In laser safety, what does "beam divergence" refer to?

Beam divergence describes how much a laser beam spreads out as it propagates through space. This phenomenon is crucial in laser safety because a laser with high divergence will spread out rapidly, reducing its intensity over distance and making it less hazardous compared to a laser with low divergence that retains its intensity over a longer range.

Understanding beam divergence is essential for assessing potential hazards associated with laser use, as it directly impacts the area that might be exposed to laser light and the necessary safety precautions that must be implemented in a controlled environment. Factors influenced by beam divergence include the design of laser safety measures, determining safe distances for operation, and assessing the risk of eye exposure.

While the speed of a laser beam is constant (the speed of light) and does not relate to divergence, and while the power and energy emitted by a laser relate more to its output characteristics than to how the beam physically behaves in space, beam divergence essentially focuses on the geometric spread of the beam over distance. This makes it a critical concept for effectively managing laser safety protocols.