A laser diode is a semiconductor device that emits coherent and monochromatic light through the process of stimulated emission. It comprises a p-n junction with additional layers to create a laser cavity. When a forward voltage is applied, it allows current to flow across the junction, stimulating the emission of photons. These photons then undergo amplification through reflections between the mirrored ends of the cavity, resulting in a concentrated, high-intensity laser beam. The symbol for a laser diode is similar to that of a regular diode but with the addition of two arrows indicating the emission of light, typically labeled “LD” or “L”.
Also, see the complete list of Electrical and Electronics Engineering Symbols here.
The figure below displays the LASER diode symbol:
