What is a laser?

A laser is defined as a device that amplifies electromagnetic radiation, which is key to its function. The term "laser" actually stands for "Light Amplification by Stimulated Emission of Radiation." In this process, atoms or molecules in a medium are energized, leading to the emission of photons. These photons then stimulate further emissions, resulting in a coherent beam of light with specific properties such as monochromaticity and collimation.

Electromagnetic radiation encompasses a range of wavelengths, including visible light, ultraviolet, infrared, and more. In the context of lasers, the amplification process allows a focused, high-intensity beam to be directed towards a target for various applications, such as medical treatments, industrial cutting, or communication technologies. This essential mechanism sets lasers apart from other optical instruments and devices, which do not have the capacity for such amplification of light.