What is Infrared and how does it work?

When we see the light, we can imagine a hot sunny day or the soothing glow of a nightlight. However, visible light, which is the only light that our eyes can perceive, makes up for only a small fraction of all the light in the universe. Not only visible and infrared light are present in the spectra but other lights are also observed. It includes gamma rays, ultraviolet, x-rays, radio, and microwaves.

Infrared is the portion of the electromagnetic spectrum starting from the end of the visible range to the microwave range with a wavelength range 700 nm-1 mm. The wavelength of infrared is longer than visible light and shorter than radio waves. Infrared radiation, being invisible to the human eyes, gives a warm sensation to the skin. Correspondingly, the frequency ranges from 300 GHz to 400 THz, lower than the visible range but higher than those of microwaves.

Wavelength and frequency

Based on wavelength, the infrared region can be further divided into multiple portions or bands. However, there are no definite boundaries between bands. Infrared is separated into 3 types of radiation:

· Near-infrared

· Mid-infrared

· Far-infrared


The range of near-IR wavelength begins from the red end of the visible light spectrum. The range of its wavelength measures from 750 nanometers to 1,300 nanometers. The frequency of near-infrared radiation ranges from 215 THz to 400 THz. This group of infrared has the shortest frequency, longest wavelength range, and produces a very low quantity of heat.


The mid-IR band is also called an intermediate-infrared band. It comes after the near-IR band, which covers wavelengths ranging from 1300 nm to 3,000 nm or (1.3-3 microns). The frequency range of mid-IR is from 20 THz to 215 THz.


Far-infrared wavelength is closest to microwaves, having a range between 3,000 nanometers to 1 millimeter. This infrared group has the shortest wavelength ranging 3-1,000 microns, has the longest frequency of about 0.3 THz to 20 THz and produces more heat as compared to near-IR.

How does infrared work?

Infrared technology is found in everyday life and on every household device. For example, the television has an infrared sensor that sends the signals from the remote to control the motion on the TV. The passive IR sensor is for the movement detection system and the LDR sensor (light dependent resistor) is for outdoor lighting. When infrared radiation emits from the IR transmitter, it reaches the body and some of it reflects the receiver. The output of the sensor is determined by the intensity of the IR receiver.

In simple words, infrared radiation is emitted from a body when it is heated. The IR radiation is converted into heat, resulting in the vibration of atoms and molecules in the body. The object produces infrared radiation when it is not heated enough to radiate visible light. Infrared sensors are very beneficial due to their portable features, low power requirement, and simple circuitry.

The working principle of infrared sensors is governed by 3 laws:

Planck’s law of radiation – The temperature T of every object not equal to 0 Kelvin emits radiation

Boltzmann law – The total energy emitted by a black body is linked to the absolute temperature T at all wavelengths

Wein’s law of displacement – Different temperature of objects at different wavelength emits spectra

Infrared sensors are used in LED lights and lasers with a specific wavelength of IR working on these principles of radiation. The sources of infrared radiation are tungsten lamps, silicon carbide, and blackbody radiators. These devices are available at Healthy Line for PEMF therapy and far-infrared therapy.

Other applications of infrared

The infrared sensors are used in many other devices such as:

· Radiation thermometers

· Night vision devices

· Infrared imaging devices

· Gas detectors

· Moisture Analyzers

· Flame monitoring devices

Here in this article, we have explained the details of infrared and its working. Various infrared-oriented devices are manufactured by Healthy Line for household use and also for IR therapy to provide relaxation to the body to enjoy a healthy lifestyle.

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