What is it when the non-reflective surface changes the geometry/properties of the beam, causing the laser beam to spread, thus becoming less collimated and less hazardous?

• A. Diffuse Reflection
• B. Specular Reflection
• C. Refraction
• D. Absorption

Answer: (A)

When a beam hits a rough, non-ideal surface, the tiny facets reflect light in many different directions rather than in a single, mirrored angle. This spreading is diffuse reflection, which destroys collimation and disperses energy, making the beam less hazardous at a distance because its intensity becomes more spread out. If the surface were smooth and reflected light like a mirror, it would be specular reflection, preserving direction and collimation. Refraction would bend the beam as it enters a new medium, not spread it at the surface, and absorption would simply remove energy rather than scatter it.