Lasers, LEDs and light sources are devices that create light. LEDs (light emitting diodes) convert an electrical current into light using spontaneous emission in optically active semiconductors.

The emergence of convenient sources of broadband light spanning the visible and near-infrared is proving increasingly useful for applications involving spectroscopy, imaging and metrology ...

Lots of different sources produce light. Earth's main source of natural light is the Sun. At night, moonlight is created by the moon reflecting the Sun's light. This allows us to see at night ...