We explain what infrared rays are, their types, history and characteristics. In addition, its uses and main applications.
What are infrared rays?
Infrared radiation, popularly known as infrared rays, is a form of radiation that is part of the electromagnetic spectrum, but it has a shorter wavelength than the light visible (although greater than microwaves). These are electromagnetic waves whose lengths of wave they are between 0.7 and 1000 microns.
Since it is not part of the visible spectrum, our eyes are unable to perceive infrared radiation, although we can detect it as a sensation of heat on the skin, for example, when we are exposed to the sun's radiation.
Also, any kind of matter to present a temperature above 0 degrees Kelvin (that is, -273.15 degrees Celsius, the so-called "absolute zero") emits a certain level of radiation of this type. In fact, living beings we emit a significant amount of infrared radiation due to our body heat.
On the other hand, depending on their location within the wavelength range, infrared rays can be of three types:
- Near infrared. They are between 0.78 and 2.5 micrometers (it is the range closest to the visible spectrum).
- Mid infrared. They are between 2.5 and 50 microns.
- Far infrared. They are between 50 and 1000 microns.
Infrared rays have an important presence in the nature. In addition, they have various applications in industry.
Infrared ray characteristics
The characteristics of infrared radiation are as follows:
- They are a form of electromagnetic radiation that is outside the visible spectrum (we cannot see it with the naked eye).
- Their wavelengths vary between 0.7 and 1000 micrometers and their frequency values are between 3 x 1011 and 3.84 x 1014
- It is emitted by all bodies whose temperature is above absolute zero, in particular, by living beings, and is perceived as a form of surface heat.
History of infrared rays
The existence of infrared radiation was discovered at the beginning of the 19th century, by the British-German musician and astronomer William Herschel (1738-1822), also discoverer of the planet Uranus.
Herschel used a thermometer of mercury to measure the temperature of light in the visible spectrum, emitted through an optical prism. Thus he discovered that the values were higher towards the red side of the spectrum and that, even when it left it (that is, when it went beyond the visible red), the registered heat continued to increase. This led him to conclude that he was in the presence of an invisible form of light, which he called "heat rays."
This experiment was replicated in the first bolometers (devices for measuring electromagnetic radiation) with which the infrared spectrum began to be studied, measuring the temperature values of light.
Uses of infrared rays
Infrared radiation has many human applications today:
- Night vision equipment. Through infrared light detectors, optical devices are manufactured that translate it into the visible spectrum, and allow us to "see" in the dark, being guided by the heat emitted by objects. These implements are widely used in the war industry.
- Remote controls. The use of infrared emitters in remote controls and other remote devices is common, which would otherwise have to use radio waves and generate “ambient noise” for other more important forms of transmission of radio waves. data, As the Wifi.
- Infrared digital transmission. This type of technology data transmission (between computers or between computers and their peripherals nearby) uses infrared signals to transmit data over a short distance.
- Spectroscopic study in astronomy. By measuring the infrared radiation in the atmosphere of cool stars, astronomers are able to study the chemical elements present in them. These rays are also used to study molecular clouds in space.
- Surveillance and security. Measuring temperature levels in a closed environment allows new forms of surveillance and security, such as that applied at airports during periods of pandemic, to detect abnormal temperature levels in a mass of people in movement.