What is the active medium used in diode lasers?

The active medium in diode lasers is a semiconductor diode. In these types of lasers, the semiconductor material serves as the medium where electron-hole pairs are created and recombine to emit photons. This process is known as electroluminescence. When current is applied to the semiconductor diode, it allows controlled emission of light, making it efficient for various applications, particularly in dentistry and periodontology.

This understanding of semiconductor diodes highlights their importance in producing coherent light effectively. Other options mentioned, like CO2 gas or nitrogen and helium, do not apply to diode lasers, which distinctly utilize semiconductor technology rather than gas mediums. Ergonomic crystals might relate to other laser types, such as solid-state lasers, but they are not involved in the operation of diode lasers.