What is the part of the laser that contains the active medium called?

The part of the laser that contains the active medium is referred to as the resonator cavity. This component plays a crucial role in the functioning of a laser.

Within the resonator cavity, the active medium, which can be a gas, liquid, or solid, is stimulated to emit light. The design of the resonator cavity allows for the amplification of this emitted light through repeated reflections between mirrors placed at either end of the cavity. One of these mirrors is typically partially reflective, enabling some light to escape, which forms the output beam of the laser.

This amplification process, facilitated by the resonator cavity, is essential for producing a coherent and focused beam of light characteristic of lasers. Understanding the function of this cavity is vital for grasping how lasers operate and the principles underlying their design and usage in various applications, including electrolysis and other forms of treatment.

Other terms, while related to the components of a laser, do not specifically describe the part containing the active medium in the same way that "resonator cavity" does.