Semiconductor lasers, also known as laser diodes, are devices that convert electrical energy into light through a process called electroluminescence. They are made from semiconductor materials, typically gallium arsenide or indium phosphide, which allow for efficient light emission when an electric current passes through them. These lasers are compact, energy-efficient, and widely used in various applications, including optical communication and consumer electronics. The operation of semiconductor lasers relies on a p-n junction, where positive and negative charge carriers recombine to produce photons. The emitted light is then amplified within a resonant cavity, creating a coherent beam. Their small size and ability to be integrated into circuits make them essential in modern technology, including fiber optic networks and laser printers.