Luminescence

Luminescence

Luminescence is a physical phenomenon where a substance emits light without being heated to a high temperature. It is a type of cold light generated by absorbing energy from external sources such as light, electricity, or chemical reactions.

In everyday use, such as choosing a flashlight, luminescence is most commonly associated with LED (Light Emitting Diode) technology. This allows for compact, energy-efficient, and high-performance lighting solutions.

The intensity of emitted light is measured in lumens (lm). The more lumens, the greater the luminous flux—and the longer the beam distance. For instance, a tactical penlight rated at 140 lumens can illuminate up to 70 meters.

There are several types of luminescence depending on the excitation method, including photoluminescence, chemiluminescence, bioluminescence, and electroluminescence.