Total internal reflection (TIR) plays a key role in laser technologies by helping to confine and guide light within specific components of laser systems.
In solid-state and semiconductor lasers, TIR is used to keep light trapped within the gain medium or optical cavity. The light reflects back and forth between mirrors or between surfaces designed to cause TIR, allowing it to pass repeatedly through the gain medium. This repeated passage amplifies the light through stimulated emission, which is essential for laser operation.
In optical fibers used to deliver laser beams (e.g., in surgery or communication), TIR keeps the laser light confined within the fiber core. This ensures minimal loss of energy and precise delivery of high-intensity laser beams over long distances or to specific target areas.
In laser resonators, angled surfaces or prism-like geometries can use TIR to direct the beam along a controlled path, contributing to beam shaping and alignment.
TIR also enables compact laser designs, reducing the need for mirrors or coatings that might degrade under high intensities. Since TIR has nearly 100% reflectivity under ideal conditions, it ensures maximum efficiency and stability of the laser system.