Retrorefraction

Retrorefraction is a phenomenon in optics where light is reflected back in the exact opposite direction of its incoming path. This occurs due to the specific arrangement of reflective surfaces within a retroreflector, which is a device designed to reflect light back to its source. The most common type of retroreflector is the corner cube retroreflector, which consists of three mutually perpendicular mirrors. When light enters the corner cube, it is reflected off each of the three mirrors and exits in a direction that is parallel to the incoming light but in the opposite direction. This property makes retroreflectors highly useful in various applications, including road signs, reflective markers, and laser ranging systems. The efficiency of retroreflection is typically measured by the retroreflective coefficient, which quantifies the fraction of incident light that is reflected back to the source. Retroreflectors are valued for their ability to provide a strong, directional reflection, making them indispensable in fields that require precise optical feedback.