What happens at the critical angle in fiber optics?

At the critical angle in fiber optics, light undergoes total internal reflection. This phenomenon occurs when light traveling through a medium, such as the glass of an optical fiber, hits the boundary with another medium (like air) at an angle that is greater than the critical angle. When this happens, the light does not pass into the second medium; instead, it is completely reflected back into the fiber. This is essential for the efficiency of optical fibers, allowing them to conduct light over long distances with minimal loss.

The concept of critical angle is fundamental to the design and functionality of optical fibers. It ensures that light signals can be transmitted efficiently, without escaping the fiber into the surrounding environment. Hence, total internal reflection maximizes the amount of light that remains in the fiber and travels along its length, which is crucial for applications in telecommunications and imaging.