A diode laser is a type of laser that uses a semiconductor as its gain medium. It works by passing an electric current through the semiconductor material, which causes it to emit light. This light is then amplified and focused to produce a coherent beam. Diode lasers are commonly used in various applications, including optical communication, laser printers, and barcode scanners. These lasers are compact, efficient, and relatively inexpensive compared to other types of lasers. They can emit light in different wavelengths, making them versatile for different uses. Diode lasers are also found in medical devices and consumer electronics, highlighting their importance in modern technology.