What is the purpose of a laser's output coupler?

The purpose of a laser's output coupler is to allow a portion of the amplified light to escape from the laser cavity while reflecting the remaining light back into the gain medium. This component is crucial because it achieves the balance between generating a coherent and intense beam of light while maintaining the necessary feedback that promotes further amplification within the laser cavity.

The output coupler typically has a partially reflective coating that permits some of the light to exit, forming the laser beam, while still reflecting enough light back into the laser medium to sustain the amplification process. This design is vital for ensuring that the laser produces a stable output of light with the desired properties, such as coherence and directionality.

In contrast, other options pertain to different aspects of laser operation that do not specifically describe the function of the output coupler. For instance, increasing the power of the laser relates more to the gain medium and pumping energy rather than the output coupler. Temperature stabilization and vibration prevention are factors that may affect laser performance but are not direct functions of the output coupler itself. Therefore, understanding the role of the output coupler is essential for comprehending how lasers produce their characteristic beams.