IR (infrared) is our middle name. Well, technically, it’s our first name. When I say middle name, I mean we know a lot about it. If that seems confusing, ask 10 people what IR is. You will probably get 11 different definitions.
Many words have a common definition and a technical definition. In the military, it gets particularly confusing, so I hope I can clarify some things for you.
Common Speech
IR (infrared): The near infrared energy
Technically correct:
IR (infrared): The near, mid, and far infrared energy
Thermal Infrared: The mid and far infrared energy
Night Vision: A device using near infrared energy for imaging, commonly called NVG (night vision goggles)
Thermal Imaging: A device using mid or far infrared energy for imaging
Years ago, the military released night vision goggles(NVG) to its soldiers. The night vision goggles were sensitive to near infrared energy so they were often called “IR” goggles. We only cared about the near infrared energy so that worked fine.
The near infrared energy behaves more like visible red light except that you can’t see with the naked eye. There are LEDs (your TV remote control) and LASERs that emit near infrared. Near infrared is used EXTENSIVELY in fiber optic communications. Most likely, the data for you to read this was sent to you as tiny pulses of near infrared energy.
Mid and far infrared are similar to each other, but very different from near infrared and visible energy. The warmth you feel when you stand next to a wood stove or radiator is comprised of mid and far infrared. All objects in the world are continually giving off and receiving mid and far infrared. If I am near a wall, I will radiate energy in the form of mid and far infrared to the wall and the wall will do the same to me. However, if I am warmer than the wall, the amount I transmit to the wall will be more than what the wall transmits to me. Therefore, the wall will cool me off some.
So let me be clear
Infrared is more than Near
Mid and Far are close by
But never seen by the naked eye
Be assured these three are one
The infrared spectrum gets the job done!