Täysheijastuspeilit

Täysheijastuspeilit, also known as total internal reflection mirrors, are optical devices designed to reflect almost all incident light. This is achieved by utilizing the phenomenon of total internal reflection. When light travels from a denser medium (like glass or plastic) to a less dense medium (like air) at an angle greater than the critical angle, it is completely reflected back into the denser medium instead of refracting out. Täysheijastuspeilit are constructed so that this condition is met for the light that enters them.

Unlike metallic mirrors which absorb a small percentage of light and can degrade over time, täysheijastuspeilit can offer very high reflectivity, often exceeding 99%. This makes them ideal for applications where light loss must be minimized. They are commonly found in optical instruments such as binoculars, telescopes, and cameras, where they redirect light paths efficiently. In laser systems, they are crucial for guiding the laser beam with minimal power reduction.

The critical angle, which determines when total internal reflection occurs, depends on the refractive indices of the two media involved. For a glass-to-air interface, the critical angle is around 42 degrees. Täysheijastuspeilit are designed with specific geometries, often right-angled prisms, to ensure that light strikes the internal surface at an angle greater than this critical angle, thereby achieving total internal reflection. They are robust and do not require reflective coatings that can be easily damaged.