What is the main output of a laser diode?

The main output of a laser diode is coherent light. Laser diodes function based on the principles of stimulated emission, which leads to the generation of light that has a very specific wavelength and phase relationship. This coherence results in light waves that travel in unison, making laser light well-defined in both frequency and direction.

In contrast to incoherent light, which is produced by typical light sources like incandescent bulbs and consists of waves that are not in phase and have a range of wavelengths, the coherent light produced by laser diodes is highly focused and can travel over long distances with minimal divergence. This property is crucial for applications in communication, medical devices, and various optical systems.

While ultrasound waves and heat energy can be associated with other forms of energy conversion or emission, they do not represent the primary output of laser diodes, which is specifically the coherent light.