Optical resonators are devices that confine light, allowing it to bounce back and forth between mirrors. This process enhances the light's intensity and can produce specific wavelengths, making them essential in lasers. The arrangement of mirrors and the distance between them determine the resonator's properties and the types of light it can generate. These resonators are commonly found in various applications, including lasers, fiber optics, and optical communication systems. By controlling the light's behavior, optical resonators play a crucial role in improving the efficiency and performance of these technologies.