polarized light often used to dampen light specularly reflected from smooth dielectric surfaces. Polaroid sunglasses, for example, are based on this principle. When natural unpolarized light falls on the surface of a body of water, some of it is specularly reflected and polarized. This reflected light makes it difficult to see underwater objects. When looking at the water through a properly oriented polarizer, most of the specularly reflected light will be absorbed and the visibility of underwater objects will be greatly improved. When viewed through such glasses, the "noise" - light reflected from the surface - is reduced by 5-20 times, and the "signal" - light from underwater objects - is reduced by only 2-4 times. Thus, the signal-to-noise ratio increases significantly.
polarizing microscopy. Polarizing microscopy is widely used in a number of studies. The polarizing microscope is equipped with two polarizing prisms or two polaroids. One of them - the polarizer - is located in front of the condenser, and the second - the analyzer - behind the lens. In recent years, special polarization compensators have been introduced into polarizing microscopes, which significantly increase the sensitivity and contrast. Using microscopes with compensators, such small and low-contrast objects as intracellular birefringent structures and details of the structure of cell nuclei that cannot be detected in any other way were detected and photographed.
Enhance contrast. Polarizing filters are often used to enhance the contrast of transparent and low contrast elements. So, for example, they are used when photographing a cloudy sky in order to enhance the contrast between clouds and a clear sky. The light scattered by clouds is almost completely unpolarized, while the light from a clear blue sky is significantly polarized. The use of polarizing filters is the most effective means of enhancing contrast.
Crystallographic studies and photoelastic analysis. In crystallography, polarization studies are carried out especially frequently. Many crystals and oriented polymer materials exhibit significant birefringence and dichroism. By studying these characteristics and determining the direction of the corresponding axes, it is possible to identify materials, as well as obtain data on the chemical structure of new substances.
Of particular importance in technology is photoelastic analysis. This is a method that allows one to judge mechanical stresses by phase shift. For photoelastic analysis, the part under study is made of a transparent material with a high photoelasticity coefficient. The main part of the installation for photoanalysis is a polariscope, consisting of an illumination system, a polarizer, an analyzer and an eyepiece. If a flat glass strip is subjected to stretching, the glass will be somewhat deformed, and mechanical stresses will arise in it. As a result, it will become birefringent and will shift the phase of the light wave. By measuring the phase shift, the magnitude of the voltage can be determined.
Photoelastic analysis method can also be used in ophthalmology, since photoelastic phenomena have been found in the membranes of the eye.
V. MURAKHVERI
The phenomenon of light polarization, studied both in school and institute physics courses, remains in the memory of many of us as a curious optical phenomenon that finds application in technology, but is not encountered in everyday life. The Dutch physicist G. Kennen, in his article published in the journal Natuur en Techniek, shows that this is far from being the case - polarized light literally surrounds us.
The human eye is very sensitive to the color (i.e., wavelength) and brightness of light, but the third characteristic of light, polarization, is practically inaccessible to it. We suffer from polarization blindness. In this respect, some representatives of the animal world are much more perfect than us. For example, bees distinguish polarization of light almost as well as color or brightness. And since polarized light is often found in nature, it is given to them to see something in the world around them that is completely inaccessible to the human eye. It is possible to explain to a person what polarization is, with the help of special light filters, he can see how light changes if polarization is "subtracted" from it, but we apparently cannot imagine a picture of the world through the "eyes of a bee" (especially since the vision of insects is different from the human and in many other respects).
Rice. one. Scheme of the structure of the visual receptors of humans (left) and arthropods (right). In humans, rhodopsin molecules are arranged randomly with the folds of the intracellular membrane, in arthropods - on the outgrowths of the cell, in neat rows.
Polarization is the orientation of the oscillations of a light wave in space. These vibrations are perpendicular to the direction of the light beam. An elementary light particle (quantum of light) is a wave that can be compared for clarity with a wave that will run along a rope if, after fixing one end of it, shake the other with your hand. The direction of rope vibration can be different, depending on which direction to shake the rope. In the same way, the direction of quantum wave oscillations can be different. A beam of light consists of many quanta. If their vibrations are different, such light is not polarized, but if all the quanta have exactly the same orientation, the light is called completely polarized. The degree of polarization can be different depending on what fraction of quanta in it has the same orientation of oscillations.
There are filters that pass only that part of the light, the waves of which are oriented in a certain way. If you look at polarized light through such a filter and turn the filter, the brightness of the transmitted light will change. It will be maximum when the direction of transmission of the filter coincides with the polarization of light, and minimum when these directions are completely (by 90°) divergent. A filter can detect polarizations in excess of about 10%, and special equipment detects polarizations of the order of 0.1%.
Polarizing filters, or Polaroids, are sold at photo supply stores. If you look at a clear blue sky through such a filter (when cloudy, the effect is much less pronounced) at about 90 degrees from the direction to the Sun, that is, so that the Sun is on the side, and at the same time turn the filter, then it is clearly visible that at a certain position of the filter in the sky a dark line appears. This indicates the polarization of the light emanating from this area of the sky. The polaroid filter reveals to us a phenomenon that bees see with the "simple eye". But one should not think that the bees see the same dark stripe in the sky. Our position can be compared to that of a complete colorblind person, a person unable to see colors. Anyone who distinguishes only black, white and various shades of gray, could, looking at the world around him alternately through light filters of various colors, notice that the picture of the world is somewhat changing. For example, through a red filter, a red poppy would look different against a background of green grass; through a yellow filter, white clouds in a blue sky would stand out more strongly. But filters would not help a colorblind person understand what the world looks like for a person with color vision. Just like color-blind filters, a polarizing filter can only tell us that the light has some property that is not perceived by the eye.
The polarization of the light coming from the blue sky can be noticed by some with the naked eye. According to the famous Soviet physicist Academician S.I. Vavilov, 25 ... 30% of people have this ability, although many of them are not aware of it. When observing a surface that emits polarized light (for example, the same blue sky), such people may notice a faint yellow strip with rounded ends in the middle of the field of view.
Rice. 2.
The bluish spots in its center and along the edges are even less visible. If the plane of polarization of the light rotates, then the yellow strip also rotates. It is always perpendicular to the direction of light vibrations. This is the so-called Heidinger figure, it was discovered by the German physicist Heidinger in 1845. The ability to see this figure can be developed if you manage to notice it at least once. Interestingly, back in 1855, not being familiar with the article by Haidinger, published nine years earlier in a German physics journal, Leo Tolstoy wrote (Youth, Chapter XXXII): “... I involuntarily leave the book and peer into the open door of the balcony, into the curly hanging branches of tall birches, on which the evening shadow is already setting, and into the clear sky, on which, as you look intently, a dusty yellowish speck suddenly appears and disappears again ... ” Such was the observation of the great writer.
Rice. 3.
In unpolarized light ( 1 ) oscillations of the electric and magnetic components occur in a variety of planes, which can be reduced to two, highlighted in this figure. But there are no oscillations along the beam propagation path (light, unlike sound, is not longitudinal oscillations). In polarized light ( 2 ) one vibration plane is singled out. In light polarized in a circle (circularly), this plane is twisted in space by a screw ( 3 ). A simplified diagram explains why reflected light is polarized ( 4 ). As already mentioned, all oscillation planes existing in the beam can be reduced to two, they are shown by arrows. One of the arrows looks at us and is conventionally visible to us as a dot. After reflection of light, one of the directions of oscillations existing in it coincides with the new direction of propagation of the beam, and electromagnetic oscillations cannot be directed along the path of their propagation.
The Haidinger figure can be seen much more clearly when viewed through a green or blue filter.
The polarization of light from a clear sky is just one example of polarization phenomena in nature. Another common case is the polarization of reflected light, glare, for example, lying on the surface of water or glass showcases. Actually, photographic polaroid filters are designed so that the photographer can, if necessary, eliminate these interfering glare (for example, when shooting the bottom of a shallow reservoir or photographing paintings and museum exhibits protected by glass). The action of polaroids in these cases is based on the fact that the reflected light is polarized to one degree or another (the degree of polarization depends on the angle of incidence of light and at a certain angle, which is different for different substances, the so-called Brewster angle, the reflected light is completely polarized). If we now look at the glare through a polaroid filter, it is not difficult to find such a turn of the filter at which the glare is completely or to a large extent suppressed.
The use of polaroid filters in sun glasses or windshields allows you to remove interfering, blinding glare from the surface of the sea or a wet highway.
Why is reflected light and scattered sky light polarized? A complete and mathematically rigorous answer to this question is beyond the scope of a small popular science publication (readers can find it in the literature listed at the end of the article). The polarization in these cases is due to the fact that the vibrations even in an unpolarized beam are already "polarized" in a certain sense: light, unlike sound, is not longitudinal, but transverse vibrations. There are no oscillations in the beam along the path of its propagation (see diagram). Oscillations of both the magnetic and electrical components of electromagnetic waves in an unpolarized beam are directed in all directions from its axis, but not along this axis. All directions of these oscillations can be reduced to two, mutually perpendicular. When the beam is reflected from the plane, it changes direction and one of the two directions of oscillation becomes "forbidden", as it coincides with the new direction of beam propagation. The beam becomes polarized. In a transparent substance, part of the light goes deep, being refracted, and the refracted light is also polarized, although to a lesser extent than the reflected one.
The scattered light of the sky is nothing but sunlight, which has undergone multiple reflections from air molecules, refracted in water droplets or ice crystals. Therefore, in a certain direction from the Sun, it is polarized. Polarization occurs not only with directional reflection (for example, from the water surface), but also with diffuse reflection. So, with the help of a polaroid filter, it is easy to verify that the light reflected from the highway pavement is polarized. In this case, an amazing dependence operates: the darker the surface, the more polarized the light reflected from it. This dependence is called Umov's law, after the Russian physicist who discovered it in 1905. An asphalt highway, in accordance with Umov's law, is more polarized than a concrete one, and a wet one is more polarized than a dry one. A wet surface is not only more shiny, but it is also darker than a dry one.
Note that the light reflected from the surface of metals (including from mirrors - after all, each mirror is covered with a thin layer of metal) is not polarized. This is due to the high conductivity of metals, due to the fact that they have a lot of free electrons. The reflection of electromagnetic waves from such surfaces occurs differently than from dielectric, non-conductive surfaces.
The polarization of sky light was discovered in 1871 (according to other sources, even in 1809), but a detailed theoretical explanation of this phenomenon was given only in the middle of our century. However, as historians studying the ancient Scandinavian sagas of Viking voyages have discovered, brave sailors almost a thousand years ago used the polarization of the sky to navigate. Usually they sailed, guided by the Sun, but when the sun was hidden behind continuous clouds, which is not uncommon in northern latitudes, the Vikings looked at the sky through a special “sun stone”, which made it possible to see a dark strip in the sky at 90 ° from the direction of the Sun if the clouds are not too dense. From this band you can judge where the Sun is. “Sun Stone” is apparently one of the transparent minerals with polarization properties (most likely Icelandic spar, common in northern Europe), and the appearance of a darker band in the sky is explained by the fact that, although the Sun is not visible behind the clouds, the light of the sky penetrating through the clouds, remains somewhat polarized. Several years ago, testing this assumption of historians, a pilot flew a small plane from Norway to Greenland, using only a crystal of the cordierite mineral, which polarizes light, as a navigational device.
It has already been said that many insects, unlike humans, see the polarization of light. Bees and ants, no worse than the Vikings, use this ability to orient themselves in cases where the Sun is covered by clouds. What gives the eye of insects this ability? The fact is that in the eye of mammals (including humans) the molecules of the light-sensitive pigment rhodopsin are arranged randomly, and in the eye of an insect the same molecules are stacked in neat rows, oriented in one direction, which allows them to react more strongly to the light whose vibrations correspond to the plane of placement of molecules. The Haidinger figure can be seen because part of our retina is covered with thin, parallel fibers that partially polarize light.
Curious polarization effects are also observed in rare celestial optical phenomena, such as rainbows and haloes. The fact that the light of the rainbow is highly polarized was discovered in 1811. By rotating the polaroid filter, you can make the rainbow almost invisible. The light of the halo is also polarized - luminous circles or arcs that sometimes appear around the Sun and Moon. In the formation of both a rainbow and a halo, along with refraction, light reflection is involved, and both of these processes, as we already know, lead to polarization. Polarized and some types of aurora.
Finally, it should be noted that the light of some astronomical objects is also polarized. The most famous example is the Crab Nebula in the constellation Taurus. The light emitted by it is the so-called synchrotron radiation, which occurs when fast-flying electrons are decelerated by a magnetic field. Synchrotron radiation is always polarized.
Returning to Earth, we note that some species of beetles, which have a metallic sheen, turn the light reflected from their back into a polarized circle. This is the name of polarized light, the plane of polarization of which is twisted in space in a helical direction, to the left or to the right. The metallic reflection of the back of such a beetle, when viewed through a special filter that reveals circular polarization, turns out to be left-handed. All these beetles belong to the family of scarabs. What is the biological meaning of the described phenomenon is still unknown.
Literature:
- Bragg W. World of Light. The world of sound. Moscow: Nauka, 1967.
- Vavilov S.I. Eye and Sun. Moscow: Nauka, 1981.
- Vener R. Polarized light navigation in insects. Journal. Scientific American, July 1976
- Zhevandrov I.D. Anisotropy and optics. Moscow: Nauka, 1974.
- Kennen G.P. Invisible light. polarization in nature. Journal. Natuur en tekhniek. No. 5. 1983.
- Minnart M. Light and color in nature. Moscow: Fizmatgiz, 1958.
- Frisch K. From the life of bees. M.: Mir, 1980.
Science and life. 1984. No. 4.
a) Polarizing filters.
Light reflected from water, from other dielectrics, contains bright glare, blinding the eyes, worsening the image. Glare, due to Brewster's law, has a polarized component, in which the light vectors are parallel to the reflecting surface. If a polarizing light filter is placed in the path of the glare light, the transmission plane of which is perpendicular to the reflecting surface, then the glare will be extinguished completely or partially. Polarizing filters are used in photography, on submarine periscopes, in binoculars, microscopes, etc.
b). Polarimeters, saccharimeters.
These are devices that use the property of plane-polarized light to rotate the plane of oscillation in substances that are called optically active, such as solutions. The angle of rotation is proportional to the optical path and the concentration of the substance:
In the simplest case, a polarimeter is a polarizer and an analyzer placed in series in a beam of light. If their transmission planes are mutually perpendicular, then light does not pass through them. By placing an optically active substance between them, enlightenment is observed. By turning the analyzer through the angle of rotation of the oscillation plane φ, complete blackout is again achieved. Polarimeters are used to measure the concentration of solutions, to study the molecular structure of substances.
in). Liquid crystal indicators.
Liquid crystals are substances whose molecules are either in the form of filaments or flat disks. Even in a weak electric field, the molecules are oriented, and the liquid acquires the properties of a crystal. In a liquid crystal display, the liquid is located between the polaroid and the mirror. If polarized light passes in the region of the electrodes, then on the optical path in two thicknesses of the liquid layer, the oscillation plane rotates by 90 ° and the light does not exit through the polaroid and a black image of the electrodes is observed. The rotation is due to the fact that ordinary and extraordinary beams of light propagate in the crystal at different speeds, a phase difference arises, and the resulting light vector gradually rotates. Outside the electrodes, the light comes out and a gray background is observed.
There are many uses for polarized light. Investigation of internal stresses in telescope lenses, in glass models of parts. Application of the Kerr cell as a fast photogate for pulsed lasers. Measurement of light intensity in photometers.
test questions
1. What is the purpose of installing polarizers on submarine periscopes?
2. What actions does a photographer with a polarizing filter perform when installing it on the lens before taking a picture?
3. Why is natural light polarized when reflected from dielectrics, but not polarized when reflected from metals?
4. Depict the course of natural light beams falling on the liquid crystal display of a mobile phone in the electric field and outside the field.
5. Is the light reflected from the digital wristwatch indicator natural or polarized?
6. How to arrange the polaroid transmission planes on the headlights and windshield of the car so that oncoming cars do not blind each other?
7. The intensity of light passing through the analyzer changes by a factor of two when rotated every 90 degrees. What is this light? What is the degree of polarization of light?
8. In the path of natural light, there are several parallel glass plates at the Brewster angle (Stoletov's foot). How does the degree of polarization and the intensity of the transmitted beam of light change with an increase in the number of plates?
9. In the path of natural light, there are several parallel glass plates at the Brewster angle (Stoletov's foot). How does the degree of polarization and the intensity of the reflected light beam change with an increase in the number of plates?
10. A plane polarized beam of light at the Brewster angle is incident on the surface of a dielectric. The plane of oscillations of the light vector rotates. How does the intensity depend on the angle between the plane of incidence and the plane of oscillations of the light vector?
11. If you look at a luminous point through a birefringent crystal of Icelandic spar, you can see two points. How their mutual arrangement changes if the crystal is rotated
12. If a narrow beam of light passes through a birefringent crystal, then two beams of light come out of it. How to prove that these are mutually perpendicular polarized beams?
13. If a narrow beam of light passes through a birefringent tourmaline crystal, then two beams of light come out of it. How to find out which of them is ordinary and which is an extraordinary beam of light?
14. Glare of light from a puddle blinds the eye. How should the plane of light transmission of polarized glasses be located relative to the vertical?
15. Explain how to obtain a three-dimensional image on a flat screen in a stereo cinema.
16. Explain why polarizing filters are used in microscopes?
17. How to prove that the laser beam is plane polarized light. Why does a laser produce plane polarized light?
18. How should the optical axis of a birefringent crystal be positioned so that ordinary and extraordinary beams of light propagate after passing together?
19. Ordinary and extraordinary beams of light propagate in a crystal together with different speeds V about V e
Practical applications of light polarization. The applications of light polarization for the needs of practice are very diverse. Some of them have been developed long ago and in detail and are widely used. Others are just making their way. In methodological terms, all of them are characterized by the following feature - they either allow you to solve problems that are completely inaccessible to other methods, or solve them in a completely original way, concise and effective.
Far from claiming to be a complete description of all practical applications of light polarization, we will limit ourselves to examples from various fields of activity, illustrating the breadth of application and usefulness of these methods.
One of the important everyday tasks of lighting engineering is the smooth change and adjustment of the intensity of light fluxes. Solving this problem using a pair of polarizers (for example, polaroids) has a number of advantages over other adjustment methods. The intensity can smoothly change from maximum (with parallel polaroids) to almost darkness (with crossed polaroids). In this case, the intensity changes uniformly over the entire beam cross section, and the cross section itself remains constant. Polaroids can be made in large sizes, so such pairs are used not only in laboratory equipment, photometers, sextants or sunglasses, but also in portholes of steamships, windows of railway cars, etc.
Polaroids can also be used in light-blocking systems, i.e. systems that allow light to pass through where it is needed and block out where it is not. An example is the light blocking of car headlights. If polaroids are placed on the headlights and sight glasses of cars, oriented at 45 ° to the right to the vertical, then the polaroids on the headlights and the sight glass of this car will be parallel. Consequently, the driver will have a good view of the road and oncoming cars illuminated by their own headlights. But the polaroid headlights of oncoming vehicles will be crossed with the polaroid of the vehicle's sight glass. Therefore, the blinding light of the headlights of an oncoming vehicle will be extinguished. Undoubtedly, this would make the night work of chauffeurs much easier and safer.
Another example of polarization light blocking is the lighting equipment of the operator's workplace, which must simultaneously see, for example, an oscilloscope screen and some tables, graphs or maps. The light of the lamps illuminating the tables, falling on the oscilloscope screen, worsens the contrast of the image on the screen. This can be avoided by equipping the illuminator and the screen with polaroids with mutually perpendicular orientation.
Polaroids can be useful for those who work on the water (sailors, fishermen, etc.) to extinguish specular reflections from the water, which, as we know, are partially polarized. Polarizers are widely used in photography to eliminate glare from photographed objects (paintings, glass and porcelain items, etc.). In this case, you can place polarizers between the source and the reflective surface, this helps to completely extinguish glare. This method is useful for lighting photo studios, art galleries, photographing surgical operations, and in a number of other cases.
Extinguishing of reflected light at normal or close to normal incidence can be carried out using circular polarizers. Previously, science has proven that in this case, right-circular light turns into left-circular light (and vice versa). Therefore, the same polarizer that creates a circularly polarized incident light will cancel out the reflected light.
In spectroscopy, astrophysics, and lighting engineering, polarizing filters are widely used, which make it possible to isolate narrow bands from the spectrum under study, as well as to change the saturation or hue of a color as needed. Their action is based on the fact that the main parameters of polarizers and phase plates (for example, polaroid dichroism) depend on the wavelength. Therefore, various combinations of these devices can be used to change the spectral distribution of energy in light fluxes. For example, a pair of chromatic polaroids, which are dichroic only in the visible region, will transmit red light in a crossed position, and white in a parallel position. This simplest device is convenient for lighting photo labs.
The polarization filters used for astrophysical research contain a fairly large number of elements (for example, six polarizers and five phase plates alternating with them with a certain orientation) and make it possible to obtain fairly narrow transmission bands.
Many new materials are becoming more and more firmly established in our everyday life. It is not only about some computer or other high technologies. In fairness, it should be noted that modern 100l garbage bags can be placed both waste and bulk substances for transfer and temporary storage. Bags have a sufficiently high strength, due to which they are widely used in food and chemical warehouses. Many business executives have already appreciated the advantages of these products and actively use them both in warehouse and household needs.
Balyatinskaya Ulyana, 11th grade student
The paper provides visual material for the lesson on the topic "Practical application of the phenomenon of polarization"
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Application of light polarization Completed by 11th grade student Ulyana Balyatinskaya
Polarizing microscopes The principle of operation of polarizing microscopes is based on obtaining an image of the object under study when it is irradiated with polarizing beams, which, in turn, must be generated from ordinary light using a special device - a polarizer.
Very often, when reflected from the snow cover, the surface of the water, wet snow, glass, a bright light that cuts the eyes is formed, they are called "glare". These "glare" reduce the quality of photographs, interfere with fishermen's fishing, worsen the visibility of car drivers. To suppress reflected light, polarizing lenses are used in glasses, light filters in cameras.
Polarized sunglasses Polarized sunglasses protect your eyes from glare, which is light reflected from various surfaces. Light rays are reflected from the roadway, snow lying on the ground, from the water surface, from the walls and roofs of houses. These reflected light rays form glare. Glare degrades the quality of vision, makes it difficult to see details, bright glare blinds. The reflection is stronger, the higher the reflectivity of the surface. For example, the sun's rays are strongly reflected from a wet roadway, especially when the sun is low on the horizon. Blinding the driver in these situations increases the risk of an accident on the road. Polarized sunglasses have the ability to block reflected light rays and thus improve the quality of vision, increase image contrast, and increase visual comfort in general. The device of polarized glasses The polarized glasses are equipped with special polarized glasses that have the ability to block sunlight reflected from horizontal surfaces. Polarizing lenses are usually a multi-layer structure, inside which is a transparent polarizing film. The polarizing film is installed in the lenses so that it transmits only vertically polarized light. Light rays reflected from horizontal surfaces (snowy field, water surface, etc.), on the contrary, have horizontal polarization and therefore do not pass through polarizing lenses. At the same time, the rays coming from other objects are unpolarized and therefore pass through polarized lenses and form a clear image on the retina.
Technologies for the production of glasses can be reduced to two. In the first case, crystals of a polarizing substance are applied to a film that is glued between two plastic plates that form the lens of the glasses. This technology is the cheapest. The second technology consists in placing the crystals of the polarizing substance directly in the lens glass of the glasses. This technology is much more expensive in cost, but the quality of manufacture of such glasses is much higher. The cheaper the glasses, the thinner the lenses and the thinner the layer of polarizing substance. A direct consequence of this is a poor level of polarization. Good glasses are quite expensive, but always justify the money spent on them. If we talk about prices, then quite decent glasses cost from 50 to 100 US dollars.
Selecting the color of the glasses Gray is well suited for a bright sunny day. Colors are transmitted with virtually no distortion, allowing you to see things with their natural hues. If you want to find a compromise between good contrast and natural hues, go for brown. Orange (copper) color is almost universal, but is most beautiful in cloudy weather. Most famous fishermen, for whom the success of fishing largely lies in the ability to see the fish, use these lenses. If you fish in the early morning and late afternoon, then the yellow color of the lenses is most preferable, as it allows you to use them in exceptionally low light conditions. Just do not wear such glasses in sunny weather, because the eyes require more serious protection.
Ordinary sunglasses simply darken the visible environment, do not protect against glare. Glasses with polarized lenses prevent the penetration of light reflected from various objects, only let through the light that is useful for the human eye.
Polarizing filters It is impossible to imagine modern photography without polarizing filters. It is a plate of a special material, fixed between two flat glasses and polarizing light. The whole system is mounted in a special rotating frame, on which a mark is applied showing the position of the polarization plane. A polarizing filter increases the sharpness and purity of colors in a photo, and helps eliminate glare. Due to this, the own color of objects appears better in the photo, the color saturation increases.
LCD monitor device. C consists of a layer of molecules between two transparent electrodes and two polarizing filters whose planes of polarization are perpendicular. In the absence of liquid crystals, the light transmitted by the first filter is almost completely blocked by the second one. In the absence of an electrical voltage between the electrodes, the molecules line up in a helical structure, while the polarization plane rotates 90 º before the second filter and light passes through the vertical filter without loss. If a voltage is applied to the electrodes, the molecules tend to line up in the direction of the field, which distorts the helical structure. At a sufficient field strength, almost all molecules become parallel, which leads to the opacity of the structure. By changing the voltage between the electrodes, you can control the light flux passing through the monitor. At the same time, it is not TV screens that glow, but a thin layer of liquid crystal.
The polarized light of the Bioptron device has a regulating effect on many physiological processes in the body, on the immune system, has anti-inflammatory, immunomodulatory, analgesic effects, and stimulates tissue regeneration. Under the influence of polarized light, the energy activity of the cell membrane, oxygen uptake by tissues increase, the rheological properties of blood and microcirculation, the gas exchange and transport function of blood improve, and the functional activity of all circulating leukocytes changes.
Interesting Light Polarization Facts Sunlight in a certain direction from the Sun is polarized. The polarization of the sun's rays occurs as a result of reflection from air molecules and refraction on water droplets. Therefore, using a polaroid, you can completely close the rainbow. Many insects, unlike humans, see polarized light. Bees and ants navigate well even when the Sun is hidden behind the clouds. In the human eye, the molecules of the light-sensitive pigment rhodopsin are arranged randomly, and in the eye of an insect, the same molecules are stacked in neat rows, oriented in the same direction, which allows them to respond more strongly to the light, the vibrations of which correspond to molecular planes.
By turning the crystal and watching the change in the atmospheric sunlight passing through it, the Vikings could, based on such observations, determine the direction of the Sun, even if it was below the horizon line.
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