Diode lasers utilize which type of active medium?

Diode lasers utilize a semiconductor as their active medium. In a diode laser, the gain medium consists of a p-n junction made from semiconductor materials such as gallium arsenide (GaAs). These materials enable electron-hole pair generation when an electric current is applied. When electrons recombine with holes in the semiconductor material, they emit photons in a process called spontaneous emission.

The properties of semiconductors allow for efficient confinement of carriers and photons, which is essential for laser operation. In diode lasers, the engineered layers of materials can be manipulated to achieve desired optical properties and wavelengths, making them versatile for various applications, from telecommunications to consumer electronics.

In contrast, the other options indicate different types of active media. Solid-state lasers rely on crystals or glasses, gas lasers use gas as the medium, and liquid lasers utilize liquid gain media. Understanding the unique characteristics of semiconductor lasers helps highlight their importance in modern technology and their specific operational principles compared to these other types.