Uses, Applications and Hazards of Infrared Radiation
Infrared radiation is a form of electromagnetic radiation that is part of the electromagnetic spectrum and lies beyond the visible red region of the spectrum. In this hub, I have discussed in detail the uses of infrared radiation, the applications of infrared radiation and the hazards of infrared radiation. The uses and applications are wide and I have discussed as many as I could.
If you wish to read more about infrared radiation, that is: What is infrared radiation, the discovery of infrared radiation, how infrared radiation works, the different regions of the infrared, the properties of infrared radiation and the detection of infrared radiation, please follow the link below.
Uses of Infrared radiation:
Infrared radiation is used for industrial purposes, medical applications, scientific applications and experiments, etc. Some of the most prominent and important uses of Infrared radiation are:
Night Vision versus Thermal Imaging
- Used in night vision devices to observe animals or people using the phenomenon called infrared illumination. The observant will not know that they are being observed.
- Used in astronomy to observe objects that are blurred and hidden by the interstellar dust. Infrared imaging process is used here.
- Used in astronomical telescopes that are equipped with infrared sensors and these telescopes are used to detect distant planets that are in the dusty regions of space, as they cannot be viewed using a normal telescope. They are also used to detect objects that have had a high red-shift (shifting of wavelength towards the red end of the spectrum).
Note: Night vision is different from Thermal imaging.
Night vision is seeing objects at night using infrared devices, which is basically increasing the visibility in the dark without using a visible light source. These infrared devices increase the amount of available light in the night thereby increasing visibility.
Thermal imaging is a process by which thermal images are captured and the images are totally dependant on the amount of heat (infrared radiation) emitted by a body
What is Infrared Radiation?
- Used in infrared lamps (lamps that emit infrared radiation) and these lamps are used for drying paint, wallpapers and printing inks, to keep food warm, in heaters that are used during cold weather and in heat treatments in the field of medicine
- Used in infrared lasers that produce infrared beams that can be used to read information on compact discs.
- Used in Infrared imaging devices that are used to obtain images of infrared radiation that are reflected or produced by objects, for example, heat insulation in buildings, sources of thermal pollution, mapping vegetation on the earth’s surface.
- Used in the chemical industry to determine molecular structure and composition of substances by studying their infrared emission or absorption.
- Used in the medical field to locate diseased tissues (these areas emit abnormal heat compared to the other areas) and injury by analysing the body tissue and body fluid.
- Used for military purposes where infrared imaging devices are used to locate enemy troops in the dark, detect hidden mines, arm caches, to guide anti-aircraft missiles, etc.
- Infrared radiation is used to de-ice the wings of aircraft
- It is used in cooking and heating food
- In industries they are used for welding plastics, drying prints, curing (process of hardening) coatings etc.
- Used in locating missing people and people trapped under collapsed buildings (Infrared imaging devices are used)
- Used by fire-fighters to find people inside smoke filled buildings (Infrared imaging devices are used)
- Used in archaeology to study ancient civilisations
Note: Infrared imaging devices have a lot of applications in various fields and a brief working is presented here, in case anyone wondered what they are. The basic concept behind these is:
Infrared imaging cameras have a lens and detector combination very similar to the other cameras that we use, that have lens and sensors. The lens focuses the infrared waves / energy onto an infrared sensor. This infrared sensor has an array of thousands of sensors. These sensors convert infrared energy into electrical signals which are then converted into a visible image.
Applications of Infrared radiation:
Infrared radiation has a wide range of applications. They find application in instruments that use infrared radiation for various research, analysis, study, detections, etc. Some of the most important applications are:
Infrared heating – Infrared Panels are used to emit infrared radiation to heat up the room. When radiation from these panels fall on any object like wall or floor or any other objects, the radiation is absorbed by the molecules in the objects and they start oscillating / vibrating. These molecules continue to absorb energy and their frequency of oscillation increases. When this frequency of oscillation is equal to the frequency of the infrared radiation, the molecules (the object) start to reflect back the radiation towards other objects and this process continues.
Infrared radiation is emitted till all the objects in the room are warmed up and start reflecting the radiation. Thus Infrared radiation is emitted by all objects in the room and we feel the warmth. The advantage of this method is that this type of heating prevents issues due to damp and draughts. This type of heating is a modern method to old heating mechanisms where people used fire in stone, tiled or clay stoves to heat up their houses.
Infrared lamps - These are used to keep food warm. These are lamps that emit infrared radiation.
Infrared Thermography – This is a branch of science that deals with acquiring and analysing thermal information from remote thermal imaging devices. This is used to determine the temperature of the objects remotely and is used in military and industries. This works on the principle that infrared radiation is emitted by all bodies and these radiations are detected by thermography cameras.
Tracking using Infrared - This is used on missile guidance system where the target is tracked using the infrared radiation it emits. For example, an infrared emitter (transmitter) is placed on the object that needs to be tracked and signals/radiation from this emitter are received by infrared receivers that are connected to a computer system with display unit, that will display the location of the object.
Infrared in Health care – Digital Infrared Thermal Imaging (DITI) is a technique that is used for diagnosis in the medical field. This process makes use of thermal imaging cameras that are called DITI cameras that record thermograms depending on the infrared radiation emitted by the body. These are then studied by thermologists who interpret the images for health care professionals. These find application in detecting breast cancer, detecting inflammation in the body, detecting thyroid conditions, screening for viruses etc.
Infrared radiation is used in thermotherapy which finds wide application in the treatment of high blood pressure, arthritis, heart failure, chronic fatigue, stress, toxicity, insomnia, pain relief, high cholesterol, injuries, diabetes, muscular pain etc., with the help of infrared saunas. It is also used in physiotherapy and in treatments of cancer.
Photobiomodulation – This is also called Low Level Laser Therapy (LLLT) where the patient’s affected area is exposed to low-level laser light or light emitting diodes which stimulate the function of the cell. This finds extensible use in healing oral ulcers that result from Chemotherapy and is also used to heal sport injuries, joint pains, neck pains, back pains, tissue repair, reduce inflammation etc.
Communications using Infrared – Infrared data transmission is used for short range communications, for example between computer peripherals to transfer files, remote controls. These devices make use of Infrared light emitting diodes that emit infrared radiation. This radiation is received at the receiving end by a silicon photodiode that converts infrared radiation into binary data that will be read by the receiving device. Infrared lasers are also used in optical fibre communication.
Infrared Spectroscopy – Infrared radiation is used in spectroscopy to study organic compounds and also to identify molecules by analysing their bonds.
The concept behind this is: Atoms in molecules are in their continuous state of vibration. When these molecules absorb infrared radiation, they become hot and the vibration increases. The wavelength of infrared radiation absorbed depends on the chemical bonds between atoms in molecules.
For example absorption for C-Cl bond will be different from C-C or C-O or C=O or C-H bond. All these combinations have Carbon (C) in them, but since they form a bond with a different element in each case, the bond is different. By analysing the Infrared spectrum of these substances, their composition can be determined.
In the spectrum to the right, each trough represents an absorption due to a different bond.
Infrared in Meteorology – In the field of meteorology, satellites (Geo stationary or polar orbiting) that are fitted with scanning radiometers that have infrared sensors are used to produce infrared images of clouds, land and sea on the basis of their temperatures. The images produced are in grey scale (colder areas are white or lighter shades of grey and warmer areas are black or darker shades of grey). These are used to monitor the climate and weather of earth. This helps with the study of land and water temperatures and features of the ocean and clouds too.
(Scanning Radiometers are devices that collect visible and infrared images and radiometric images of sea, land, the clouds or the atmosphere etc.)
Since infrared images do not need a source of light for the image to be recorded, the scanning process continues without interruption during the night too, allowing meteorologists to monitor and study the weather continuously. The only disadvantage is that similar temperatures show up as similar colours.
For example, a cloud and fog with the same temperature as surrounding area will create similar colours on the images.
The scanning of the ocean and its behaviour helps the shipping industry and other studies related to land and water help farmers and fishermen. Infrared sensors in satellites help detect and study pollution, fire, deforestation, volcanoes and their ash clouds, ice mapping, sandstorms, auroras, snow, ocean and air currents, etc.
Infrared in Climatology – This is the study of climates and completely different from meteorology (weather forecast for a brief period of time). The infrared radiation of the atmosphere is monitored using a pyrgeometer (an instrument that is designed to measure infrared radiation for atmospheric and material testing applications) and this helps with long term data related to earth’s climate. These data help with long term planning of so many things from building designs to farming.
Infrared Astronomy – This field deals with the study of infrared radiation emitted by objects in the Universe. In the field of astronomy, infrared telescopes are used to detect protostars and study the cores of galaxies that usually have high dust content. Since infrared telescopes are sensitive to heat, the sensors in the telescope need to be cooled and other parts shielded from heat.
(Protostars are a cloud of gas and dust in the galaxies that gradually collapse to form a hot dense core and become a star when favourable conditions and reactions take place)
History of Art (Infrared reflectography) – Infrared reflectograms (used by art conservators to see the various layers in a painting) are used to find out the basic steps involved in a painting, like its outline and other layers beneath the top paint. It will also reveal if the painting is original or a duplicate copy.
Infrared reflectography is a study of paintings by looking deep into the different layers of painting and was introduced in the late 1960s by the Dutch physicist J. R. J. Van Asperen De Boer. Infrared radiation are incident on the painting and the degree of penetration into the layers of the painting depends on the thickness and type of paint used and the wavelength of radiation.
An infrared camera is used to record the infrared radiation reflected by the painting and this generates an image called the infrared reflectogram. This reflectogram is converted to a digital format (this is black and white) on a computer, that reveals so many details about the painting that are invisible to the human eyes.
Recently laser scanning techniques have been developed and used, but the infrared reflectography has been the best one as it reveals more details of the deeper layers than the laser scanning technique.
Infrared imaging cameras – Infrared imaging is also called thermal imaging and it is the process in which infrared energy is converted into an image that the human eye can see. The warmest regions are red and then the colour changes to yellow, green, blue, violet as the temperature decreases.
Infrared imaging is used to detect heat loss in insulating systems, to monitor or detect change in blood flow in the skin and to detect overheating problems in any apparatus. They are also used for military purposes like monitoring (military surveillance), target attainment, night vision, homing, tracking.
In industries they are used to analyse the thermal efficiency of systems, to monitor the environment, for inspection in industries, for remote sensing of temperatures for predicting climate changes, for wireless communication, in spectroscopy (to study the absorption and transmission of photons in the infrared energy range), for weather forecast, etc.
Hazards of Infrared radiation:
- Strong infrared radiation can cause blindness to the eye by damaging the retina or cornea depending on the intensity of radiation and hence Infrared proof goggles need to be worn while working with them as one will not be aware of these radiations as they are invisible.
- When using infrared radiation for therapy where muscle pain and other pains are treated, care has to be taken to regulate the intensity of the radiation, otherwise it can cause severe burns.
- Elderly people can be prone to low blood pressure if exposed to infrared radiation.
- If exposed to infrared radiation for a long time, the body can lose fluid or water and this can result in dehydration.
To read more about what infrared radiation is, discovery of infrared radiation, working of infrared radiation and properties of infrared, please follow the link below.
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Thank you for reading,