Laser diodes are the most common type of lasers produced, with a wide range of uses that include fiber-optic communications, barcode readers, laser pointers, CD / DVD / Blu-ray disc reading/recording, laser printing, laser scanning, and light beam illumination. A laser diode is a small semiconductor gadget that produces strong and precise light emissions through a cycle called stimulated emission. In a semiconductor material, like gallium arsenide (GaAs), an electric current excites electrons, causing them to move to higher energy states. The emitted light waves have the same wavelength, frequency, and.