Infrared rays and their applications. Infrared radiation: influence on the human body, the effect of rays, their properties, benefits and harms, possible consequences

Infrared radiation is one of the types of electromagnetic radiation that borders on the red part of the spectrum of visible light on one side and microwaves on the other. Wavelength - from 0.74 to 1000-2000 micrometers. Infrared waves are also called “heat”. Based on the wavelength, they are classified into three groups:

shortwave (0.74-2.5 micrometers);

medium wave (longer than 2.5, shorter than 50 micrometers);

long-wavelength (more than 50 micrometers).

Infrared radiation sources

On our planet, infrared radiation is by no means uncommon. Almost any heat is the effect of infrared rays. It doesn’t matter what it is: sunlight, the warmth of our bodies or the heat emanating from heating devices.

The infrared part of electromagnetic radiation does not heat space, but the object itself. It is on this principle that the work of infrared lamps is built. And the Sun heats the Earth in a similar way.


Effect on living organisms

At the moment, science does not know any confirmed facts about the negative effects of infrared rays on the human body. Unless the mucous membrane of the eyes can be damaged due to too intense radiation.

But we can talk about the benefits for a very long time. Back in 1996, scientists from the USA, Japan and Holland confirmed a number of positive medical facts. Thermal radiation:

destroys some types of hepatitis virus;

suppresses and slows down the growth of cancer cells;

has the ability to neutralize harmful electromagnetic fields and radiation. Including radioactive;

helps diabetics produce insulin;

can help with dystrophy;

improvement of the body's condition with psoriasis.

As you feel better, your internal organs begin to work more efficiently. The nutrition of the muscles increases, and the strength of the immune system increases significantly. It is a known fact that in the absence of infrared radiation, the body ages noticeably faster.

Infrared rays are also called “rays of life”. It was under their influence that life began.

The use of infrared rays in human life

Infrared light is used no less widely than it is widespread. It will probably be very difficult to find at least one area of ​​the national economy where the infrared part of electromagnetic waves has not found application. We list the most famous areas of application:

warfare. Homing missile warheads or night vision devices are all the result of the use of infrared radiation;

thermography is widely used in science to determine overheated or supercooled parts of an object under study. Infrared imaging is also widely used in astronomy, along with other types of electromagnetic waves;

household heaters. Unlike convectors, such devices use radiant energy to heat all objects in the room. And then further, interior items give off heat to the surrounding air;

data transmission and remote control. Yes, all remote controls for TVs, tape recorders and air conditioners use infrared rays;

disinfection in the food industry

medicine. Treatment and prevention of many different types of diseases.

Infrared rays are a relatively small part of electromagnetic radiation. Being a natural way of transferring heat, not a single life process on our planet can do without it.

William Herschel first noticed that behind the red edge of the prism-derived spectrum of the Sun there was invisible radiation that caused the thermometer to heat up. This radiation was later called thermal or infrared.

Near-infrared radiation is very similar to visible light and is detected by the same instruments. Mid- and far-IR uses bolometers to detect changes.

The entire planet Earth and all objects on it, even ice, shine in the mid-IR range. Due to this, the Earth is not overheated by solar heat. But not all infrared radiation passes through the atmosphere. There are only a few windows of transparency; the rest of the radiation is absorbed by carbon dioxide, water vapor, methane, ozone and other greenhouse gases that prevent the Earth from rapidly cooling.

Due to atmospheric absorption and thermal radiation from objects, mid- and far-IR telescopes are taken into space and cooled to the temperature of liquid nitrogen or even helium.

The infrared range is one of the most interesting for astronomers. It contains cosmic dust, important for the formation of stars and the evolution of galaxies. IR radiation passes through clouds of cosmic dust better than visible radiation and allows one to see objects that are inaccessible to observation in other parts of the spectrum.

Sources

A fragment of one of the so-called Hubble Deep Fields. In 1995, a space telescope collected light coming from one part of the sky for 10 days. This made it possible to see extremely faint galaxies up to 13 billion light years away (less than one billion years from the Big Bang). Visible light from such distant objects undergoes a significant red shift and becomes infrared.

The observations were carried out in a region far from the galactic plane, where relatively few stars are visible. Therefore, most of the registered objects are galaxies at different stages of evolution.

The giant spiral galaxy, also designated M104, is located in a cluster of galaxies in the constellation Virgo and is visible to us almost edge-on. It has a huge central bulge (a spherical thickening in the center of the galaxy) and contains about 800 billion stars - 2-3 times more than the Milky Way.

At the center of the galaxy is a supermassive black hole with a mass of about a billion solar masses. This is determined by the speed of movement of stars near the center of the galaxy. In the infrared, a ring of gas and dust is clearly visible in the galaxy, in which stars are actively being born.

Receivers

Main mirror diameter 85 cm made of beryllium and cooled to a temperature of 5.5 TO to reduce the mirror's own infrared radiation.

The telescope was launched in August 2003 under the program NASA's four great observatories, including:

  • Compton Gamma-ray Observatory (1991–2000, 20 keV-30 GeV), see Sky at 100 MeV gamma rays,
  • Chandra X-ray Observatory (1999, 100 eV-10 keV),
  • Hubble Space Telescope (1990, 100–2100 nm),
  • Spitzer infrared telescope (2003, 3–180 µm).

The Spitzer telescope is expected to have a lifespan of about 5 years. The telescope received its name in honor of astrophysicist Lyman Spitzer (1914–97), who in 1946, long before the launch of the first satellite, published the article “Advantages for Astronomy of an Extraterrestrial Observatory,” and 30 years later convinced NASA and the American Congress to begin developing a space telescope. Hubble."

Sky Reviews

Near-infrared sky 1–4 µm and in the mid-infrared range 25 µm(COBE/DIRBE)

In the near-infrared range, the Galaxy is visible even more clearly than in the visible.

But in the mid-IR range the Galaxy is barely visible. Observations are greatly hampered by dust in the solar system. It is located along the ecliptic plane, which is inclined to the galactic plane at an angle of about 50 degrees.

Both surveys were obtained by the DIRBE (Diffuse Infrared Background Experiment) instrument on board the COBE (Cosmic Background Explorer) satellite. This experiment, begun in 1989, produced complete maps of infrared sky brightness ranging from 1.25 to 240 µm.

Terrestrial Application

The device is based on an electron-optical converter (EOC), which allows one to significantly (from 100 to 50 thousand times) amplify weak visible or infrared light.

The lens creates an image on the photocathode, from which, as in the case of a PMT, electrons are knocked out. Then they are accelerated by high voltage (10–20 kV), are focused by electron optics (an electromagnetic field of a specially selected configuration) and fall onto a fluorescent screen similar to a television. On it, the image is viewed through eyepieces.

Acceleration of photoelectrons makes it possible in low light conditions to use literally every quantum of light to obtain an image, but in complete darkness a backlight is required. In order not to reveal the presence of an observer, they use a near-infrared illuminator (760–3000 nm).

There are also devices that detect objects’ own thermal radiation in the mid-IR range (8–14 µm). Such devices are called thermal imagers; they allow you to notice a person, animal or heated engine due to their thermal contrast with the surrounding background.

All the energy consumed by an electric heater ultimately turns into heat. A significant part of the heat is carried away by air, which comes into contact with the hot surface, expands and rises, so that mainly the ceiling is heated.

To avoid this, heaters are equipped with fans that direct warm air, for example, to a person’s feet and help mix the air in the room. But there is another way to transfer heat to surrounding objects: infrared radiation from a heater. The hotter the surface and the larger its area, the stronger it is.

To increase the area, radiators are made flat. However, the surface temperature cannot be high. Other heater models use a spiral heated to several hundred degrees (red heat) and a concave metal reflector that creates a directed stream of infrared radiation.

> Infrared waves

What's happened infrared waves: Infrared wavelength, infrared wave range and frequency. Study infrared spectrum patterns and sources.

Infrared light(IR) - electromagnetic rays, which in terms of wavelengths exceed the visible (0.74-1 mm).

Learning Objective

  • Understand the three ranges of the IR spectrum and describe the processes of absorption and emission by molecules.

Basic moments

  • IR light accommodates most of the thermal radiation produced by bodies at approximately room temperature. Emitted and absorbed if changes occur in the rotation and vibration of molecules.
  • The IR part of the spectrum can be divided into three regions according to wavelength: far infrared (300-30 THz), mid-infrared (30-120 THz) and near-infrared (120-400 THz).
  • IR is also called thermal radiation.
  • It is important to understand the concept of emissivity to understand IR.
  • IR rays can be used to remotely determine the temperature of objects (thermography).

Terms

  • Thermography is the remote calculation of changes in body temperature.
  • Thermal radiation is electromagnetic radiation generated by a body due to temperature.
  • Emissivity is the ability of a surface to emit radiation.

Infrared waves

Infrared (IR) light is electromagnetic rays whose wavelengths exceed visible light (0.74-1 mm). The infrared wavelength range converges with the 300-400 THz frequency range and accommodates enormous amounts of thermal radiation. IR light is absorbed and emitted by molecules as they change in rotation and vibration.

Here are the main categories of electromagnetic waves. Dividing lines differ in some places, and other categories may overlap. Microwaves occupy the high-frequency portion of the radio section of the electromagnetic spectrum

Subcategories of IR waves

The IR portion of the electromagnetic spectrum occupies the range from 300 GHz (1 mm) to 400 THz (750 nm). There are three types of infrared waves:

  • Far IR: 300 GHz (1 mm) to 30 THz (10 µm). The lower part can be called microwaves. These rays are absorbed due to rotation in gas-phase molecules, molecular motions in liquids and photons in solids. Water in the earth's atmosphere is absorbed so strongly that it becomes opaque. But there are certain wavelengths (windows) used for transmission.
  • Mid-IR range: 30 to 120 THz (10 to 2.5 µm). The sources are hot objects. Absorbed by molecular vibrations (various atoms vibrate in equilibrium positions). This range is sometimes called a fingerprint because it is a specific phenomenon.
  • Nearest IR range: 120 to 400 THz (2500-750 nm). These physical processes resemble those that occur in visible light. The highest frequencies can be found with a certain type of photographic film and sensors for infrared, photography and video.

Heat and thermal radiation

Infrared radiation is also called thermal radiation. IR light from the Sun captures just 49% of the Earth's heating, with the rest being visible light (absorbed and re-reflected at longer wavelengths).

Heat is energy in a transitional form that flows due to differences in temperature. If heat is transferred by conduction or convection, then radiation can propagate in a vacuum.

To understand IR rays, we need to take a close look at the concept of emissivity.

IR Wave Sources

Humans and most of the planetary environment produce heat rays at 10 microns. This is the boundary separating the mid- and far-IR regions. Many astronomical bodies emit detectable amounts of IR rays at non-thermal wavelengths.

IR rays can be used to calculate the temperature of objects at a distance. This process is called thermography and is most actively used in military and industrial applications.


Thermographic image of a dog and cat

IR waves are also used in heating, communications, meteorology, spectroscopy, astronomy, biology and medicine, and art analysis.

Light is the key to the existence of living organisms on Earth. There are a huge number of processes that can occur due to exposure to infrared radiation. In addition, it is used for medicinal purposes. Since the twentieth century, light therapy has become a significant component of traditional medicine.

Features of radiation

Phototherapy is a special section in physiotherapy that studies the effects of light waves on the human body. It was noted that the waves have different ranges, so they have different effects on the human body. It is important to note that radiation has the greatest penetration depth. As for the surface effect, ultraviolet has it.

The infrared spectrum range (radiation spectrum) has a corresponding wavelength, namely 780 nm. up to 10000 nm. As for physiotherapy, a wavelength that ranges in the spectrum from 780 nm is used to treat a person. up to 1400 nm. This range of infrared radiation is considered normal for therapy. In simple words, the appropriate wavelength is used, namely a shorter one capable of penetrating three centimeters into the skin. In addition, the special energy of the quantum and the frequency of radiation are taken into account.

According to many studies, it has been found that light, radio waves, and infrared rays have the same nature, since they are types of electromagnetic waves that surround people everywhere. Such waves power televisions, mobile phones and radios. In simple words, waves allow a person to see the world around him.

The infrared spectrum has a corresponding frequency, the wavelength of which is 7-14 microns, which has a unique effect on the human body. This part of the spectrum corresponds to radiation from the human body.

As for quantum objects, molecules do not have the ability to vibrate arbitrarily. Each quantum molecule has a certain complex of energy and radiation frequencies that are stored at the moment of vibration. However, it is worth considering that air molecules are equipped with a wide range of such frequencies, so the atmosphere is capable of absorbing radiation in a variety of spectra.

Radiation sources

The sun is the main source of IR.

Thanks to it, objects can be heated to a specific temperature. As a result, thermal energy is emitted in the spectrum of these waves. The energy then reaches the objects. The process of transferring thermal energy is carried out from objects with a high temperature to a lower one. In this situation, objects have various radiating properties that depend on several bodies.

Sources of infrared radiation are present everywhere, equipped with elements such as LEDs. All modern TVs are equipped with remote controls, since they operate in the appropriate frequency of the infrared spectrum. They contain LEDs. Various sources of infrared radiation can be seen in industrial production, for example: in the drying of paint and varnish surfaces.

The most striking representative of an artificial source in Rus' were Russian stoves. Almost all people have experienced the influence of such a stove and also appreciated its benefits. That is why such radiation can be felt from a heated stove or radiator. Currently, infrared heaters are very popular. They have a list of advantages compared to the convection option, as they are more economical.

Coefficient value

There are several types of coefficient in the infrared spectrum, namely:

  • radiation;
  • reflection coefficient;
  • throughput factor.

So, emissivity is the ability of objects to emit radiation frequency, as well as quantum energy. May vary according to the material and its properties, as well as temperature. The coefficient has such a maximum cure = 1, but in a real situation it is always less. As for low emission ability, it is endowed with elements that have a shiny surface, as well as metals. The coefficient depends on temperature indicators.

The reflectance coefficient shows the ability of materials to reflect the frequency of study. Depends on the type of materials, properties and temperature indicators. Reflection occurs mainly on polished and smooth surfaces.

Transmittance shows the ability of objects to transmit the frequency of infrared radiation through themselves. This coefficient directly depends on the thickness and type of material. It is important to note that most materials do not have such a coefficient.

Use in medicine

Infrared light treatment has become quite popular in the modern world. The use of infrared radiation in medicine is due to the fact that the technique has healing properties. Thanks to this, there is a beneficial effect on the human body. Thermal influence forms a body in tissues, regenerates tissues and stimulates repair, accelerates physical and chemical reactions.

In addition, the body experiences significant improvements, as the following processes occur:

  • acceleration of blood flow;
  • vasodilation;
  • production of biologically active substances;
  • muscle relaxation;
  • great mood;
  • comfortable condition;
  • good dream;
  • decreased blood pressure;
  • relieving physical, psycho-emotional stress, etc.

The visible effect of treatment occurs within several procedures. In addition to the noted functions, the infrared spectrum has an anti-inflammatory effect on the human body, helps fight infection, stimulates and strengthens the immune system.

Such therapy in medicine has the following properties:

  • biostimulating;
  • anti-inflammatory;
  • detoxification;
  • improved blood flow;
  • awakening of secondary functions of the body.

Infrared light radiation, or rather its treatment, has visible benefits for the human body.

Treatment methods

Therapy is of two types, namely general and local. As for local effects, treatment is carried out on a specific part of the patient’s body. During general therapy, the use of light therapy is aimed at the entire body.

The procedure is carried out twice a day, the session duration ranges from 15-30 minutes. The general treatment course contains at least five to twenty procedures. Make sure you have infrared protection for your face ready. Special glasses, cotton wool or cardboard covers are used for the eyes. After the session, the skin becomes covered with erythema, namely redness with blurred boundaries. The erythema disappears an hour after the procedure.

Indications and contraindications for treatment

IR has the main indications for use in medicine:

  • diseases of the ENT organs;
  • neuralgia and neuritis;
  • diseases affecting the musculoskeletal system;
  • pathology of the eyes and joints;
  • inflammatory processes;
  • wounds;
  • burns, ulcers, dermatoses and scars;
  • bronchial asthma;
  • cystitis;
  • urolithiasis;
  • osteochondrosis;
  • cholecystitis without stones;
  • arthritis;
  • gastroduodenitis in chronic form;
  • pneumonia.

Light treatment has positive results. In addition to its therapeutic effect, IR can be dangerous for the human body. This is due to the fact that there are certain contraindications, which, if not observed, can cause harm to health.

If you have the following ailments, then such treatment will be harmful:

  • pregnancy period;
  • blood diseases;
  • individual intolerance;
  • chronic diseases in the acute stage;
  • purulent processes;
  • active tuberculosis;
  • predisposition to bleeding;
  • neoplasms.

These contraindications should be taken into account so as not to cause harm to your own health. Radiation intensity that is too high can cause great harm.

As for the harm of IR in medicine and in production, burns and severe redness of the skin may occur. In some cases, people developed tumors on their faces because they were exposed to this radiation for long enough. Significant harm from infrared radiation can result in the form of dermatitis, and heat stroke can also occur.

Infrared rays are quite dangerous to the eyes, especially in the range up to 1.5 microns. Long-term exposure causes significant harm, as photophobia, cataracts, and vision problems appear. Long-term exposure to IR is very dangerous not only for people, but for plants. Using optical instruments, you can try to correct your vision problem.

Impact on plants

Everyone knows that IRs have a beneficial effect on the growth and development of plants. For example, if you equip a greenhouse with an infrared heater, you can see a stunning result. Heating is carried out in the infrared spectrum, where a certain frequency is observed, and the wave is equal to 50,000 nm. up to 2,000,000 nm.

There are quite interesting facts according to which you can find out that all plants and living organisms are influenced by sunlight. Radiation from the sun has a specific range consisting of 290 nm. – 3000 nm. In simple words, radiant energy plays an important role in the life of every plant.

Considering interesting and educational facts, it can be determined that plants need light and solar energy, since they are responsible for the formation of chlorophyll and chloroplasts. The speed of light affects elongation, the nucleation of cells and growth processes, the timing of fruiting and flowering.

Microwave oven specifics

Household microwave ovens are equipped with microwaves that are slightly lower than gamma rays and X-rays. Such ovens can provoke an ionizing effect, which poses a danger to human health. Microwaves are located in the gap between infrared and radio waves, so such ovens cannot ionize molecules and atoms. Working microwave ovens do not affect people, as they are absorbed into food, generating heat.

Microwave ovens cannot emit radioactive particles, therefore they do not have a radioactive effect on food and living organisms. That is why you should not worry that microwave ovens can harm your health!

Infrared radiation is actively used in medicine, and its beneficial properties were noticed long before the advent of modern research. Even in antiquity, the heat of coals, heated salt, metal and other materials was used to treat wounds, bruises, frostbite, tuberculosis and many other diseases.

Research of the 20th-21st centuries has proven that infrared radiation has a certain effect on the external integument and internal organs, which makes it possible to use it for therapeutic and preventive purposes.

Impact of infrared radiation on the body

Infrared rays not only heat, but only a few people know about it. Since the discovery of infrared radiation by Herschel in 1800, scientists and physicians have identified the following types of effects on the human body:

  • activation of metabolism;
  • dilation of blood vessels, including capillaries;
  • activation of capillary blood circulation;
  • antispasmodic effect;
  • analgesic effect;
  • anti-inflammatory effect;
  • activation of reactions inside the cell.

When used in doses, exposure to infrared rays has a general health effect. Already today, many devices have been developed that are used in physiotherapy rooms.

Naturally, exposure should be carried out in doses to avoid overheating, burns and other negative reactions.

Methods of using infrared rays

Since infrared rays dilate blood vessels and accelerate blood flow, they are used to improve and stimulate blood circulation. When long-wave infrared rays are directed at the skin, its receptors are irritated, which causes a reaction in the hypothalamus, sending a signal to “relax” the smooth muscles of the blood vessels. As a result, capillaries, veins and arteries expand, and blood flow accelerates.

Not only the walls of blood vessels react to infrared radiation, but at the cellular level there is an acceleration of metabolism, as well as an improvement in the course of neuroregulatory processes.

Exposure to infrared rays plays an invaluable role in improving immunity. Thanks to the increased production of macrophagocytes, phagocytosis is accelerated, and a person’s immunity is strengthened at the fluid and cellular level. In parallel, there is stimulation of amino acid synthesis, as well as increased production of enzymes and nutrients.

A disinfecting effect has also been noted; infrared rays kill a number of bacteria in the human body and neutralize the effects of some harmful substances.

Medical problems that can be solved using IR radiation

Infrared therapy is used as part of the treatment, as it allows you to solve the following effects:

  • the severity of pain decreases;
  • the pain syndrome goes away;
  • water-salt balance is restored;
  • memory improves;
  • there is a lymphatic drainage effect;
  • blood circulation (including cerebral) and blood supply to tissues are normalized;
  • blood pressure normalizes;
  • toxins and heavy metal salts are eliminated faster;
  • the production of endorphin and melatonin increases;
  • hormone production is normalized;
  • pathogenic organisms and fungi are destroyed;
  • the growth of cancer cells is suppressed;
  • there is an antinuclear effect;
  • a deodorizing effect is manifested;
  • the immune system is restored;
  • Hypertonicity and increased muscle tension are relieved;
  • emotional tension goes away;
  • Fatigue accumulates less;
  • sleep is normalized;
  • the functions of internal organs return to normal.

Diseases that are treated with infrared radiation


Naturally, such a large-scale positive effect is actively used to treat a whole range of diseases:

  • bronchial asthma;
  • flu;
  • pneumonia;
  • oncological diseases;
  • formation of adhesions;
  • adenoma;
  • peptic ulcer;
  • parotitis;
  • gangrene;
  • obesity;
  • phlebeurysm;
  • salt deposits;
  • spurs, corns, calluses;
  • skin diseases;
  • vascular diseases;
  • poorly healing wounds;
  • burns, frostbite;
  • diseases of the peripheral nervous system;
  • paralysis;
  • bedsores.

Due to the fact that metabolism is activated and blood flow is normalized, including in capillaries, organs and tissues are restored much faster and return to normal operation.

With regular exposure to infrared rays on the body, inflammatory processes reverse, tissue regeneration, anti-infective protection and local resistance increase.

When emitting devices are used together with medications and physiotherapeutic procedures, it is possible to achieve positive dynamics 1.5-2 times faster. Recovery is faster and the likelihood of relapse is reduced.

A separate topic is the use of infrared ray therapy in obese patients. Here the main effect is achieved by normalizing metabolism, including cellular metabolism. Also, heating the surface of the body promotes faster disposal of accumulated fat mass. IR radiation is used in conjunction with diet and drug treatment.

Infrared radiation in sports medicine

Research into effective injury recovery treatments has shown that infrared rays speed up the healing of injuries. The practical results are quite impressive; athletes have shown such positive changes.