What does it mean if a laser beam is described as collimated?

A laser beam described as collimated means that it remains parallel as it travels through space. This characteristic allows the beam to maintain a constant diameter over long distances, minimizing divergence. This quality is essential for various applications of lasers, such as in medical treatments and manufacturing, where precision and focus are crucial for effectiveness.

In contrast, other descriptions such as spreading out quickly would imply that the light diverges over distance, which is not true of a collimated beam. Similarly, fluctuations imply variations in the beam's intensity or direction, which is not representative of a collimated laser. The production of multiple colors would refer to spectral characteristics, which is unrelated to the beam's collimation. This clarity in direction and focus is what makes collimation beneficial in most laser applications.