Light carries information in ways you may not realize. Cell phones use light to send and receive calls and messages. Car radios use light to receive music from nearby radio stations. Even in nature, light carries many kinds of information.
The electromagnetic spectrum describes all the wavelengths of frequency, both seen and unseen. The light we can see, made up of the individual colors of the rainbow, represents only a very small portion of the electromagnetic spectrum. Most of the light in the universe is invisible to our eyes.
Light travels in waves, much like the waves you find in the ocean. As a wave, light has several basic properties that describe it. One of which is frequency.
On one end of the electromagnetic spectrum are radio waves, which have wavelengths billions of times longer than those of visible light. On the other end of the spectrum are gamma rays, with wavelengths billions of times smaller than those of visible light.
In between these are what’s known as the “terahertz” frequency range, or “THz Gap”. It is called a “gap” because the technology for its generation and manipulation is still in its infancy. This band of electromagnetic frequency lies within the region between microwave and far- infrared.
Almost every molecule has a 'fingerprint' spectrum in the terahertz frequency range. Terahertz frequency is non-ionizing, meaning it doesn’t cause harm like ionizing radiation.