The laser beam is focused onto the surface of the disc, where it reads tiny pits and lands that represent binary data. The precision of the laser diode allows for high-density data storage, as the laser can accurately detect even the smallest differences in the disc's. A laser diode is a semiconductor device that converts electrical energy into coherent light through the process of stimulated emission. In a semiconductor material, like gallium arsenide (GaAs), an electric current excites electrons, causing them to move to higher energy states. It works on the same basic principle as an LED, but with an internal structure that forces photons to align in phase and direction, producing coherent laser light instead of the. A laser diode (semiconductor laser) is an electronic component that generates laser light by converting electric current into light using a semiconductor p-n junction. SEM (scanning electron microscope) image of a commercial laser diode with its case and window cut away. This article discusses the characteristics common to laser.