What are the applications of polarization of light? The application of polarized light in life

In ** stereoscopic film.

The audience is asked to wear a pair of special glasses, which are a pair of polarizers that are perpendicular to each other in the direction of transparency. Stereoscopic film is a film film that uses two lenses to capture the image of a scene from two different directions at the same time like the human eye. During the projection, two sets of films taken with two cameras are projected simultaneously, so that the two slightly different images are superimposed on the screen.

At this time, if you use your eyes directly, the picture you see is blurry, and if you want to see a three-dimensional movie, you need to install a polarizer in front of each movie machine, which is equivalent to a polarizer. The light emitted from the two projectors becomes polarized when it passes through the polarizers.

The polarizers in front of the left and right projectors are polarized perpendicular to each other, and the polarization directions of the two polarized beams produced are also perpendicular to each other. These two beams of polarized light are projected onto the screen and reflected to the audience, and the direction of the polarized light does not change. The audience uses the above polarization glasses**, and each eye only sees the corresponding polarized light image, that is, the left eye can only see the picture reflected by the left camera, and the right eye can only see the picture reflected by the right camera, so that it will produce a three-dimensional sensation like a direct **.

This is the principle of stereoscopic film. Of course, the actual projection of stereoscopic films is done with a single lens, two sets of images alternately printed on the same film film, and a complex set of devices is required. The propagation and polarization of light in crystals.

Closely related, the polarization phenomenon can be used to understand the optical properties of crystals, to fabricate optical devices for measurement, and to provide technical means such as rock and mineral identification, optical elasticity, and laser modulation. <>

Because there is a large amount of polarized light in the blue sky, the brightness of the sky can be adjusted with a polarizer, and after the polarizer is added, the blue sky will become darker, thus highlighting the white clouds in the blue sky, because there is a large amount of polarized light in the blue sky, the brightness of the sky can be adjusted with a polarizer, and after the polarizer is added, the blue sky will become darker, thus highlighting the white clouds in the blue sky. When natural light is reflected on surfaces such as glass, water, and wooden tabletops, the reflected and refracted light are polarized light, and the degree of polarization also changes when the angle of incidence changes. Objects with smooth surfaces, such as glassware, water surfaces, display cabinets, painted surfaces, plastic surfaces, etc., often appear flare or reflection, which is caused by the interference of reflected light waves.

If you add a polarizer to the shooting and rotate the polarizing lens appropriately so that the direction of transmission is perpendicular to the direction of transmission of the reflected light, the reflected light can be attenuated and the image under water or behind the glass can be clear. <>

The applications of polarized light in life include: mobile phone and computer screens; Sunglasses; 3D Movies; Disease diagnosis, etc.

The interference and diffraction phenomena of light illustrate the wave-like nature of light. The polarization of light and the birefringence phenomenon in optically anisotropic crystals further confirm the transverse wave-like nature of light. The asymmetry of the direction of vibration from the direction of propagation is called polarization, which is one of the most obvious signs that distinguishes transverse waves from longitudinal waves, and only transverse waves have polarization.

Polarization of light: The asymmetry of the direction of vibration versus the direction of propagation is called polarization, and it is one of the most obvious signs that distinguishes a transverse wave from other longitudinal waves. The phenomenon that the spatial distribution of the electric vector vibration of the light wave loses symmetry with respect to the direction of light propagation is called the polarization of light.

Only transverse waves can produce polarization, so the polarization of light is another example of the wave nature of light.

Light that contains transverse vibrations in all possible directions in a plane perpendicular to the direction of propagation, and on average, has the same amplitude in either direction, and this transverse vibration is symmetrical to the direction of propagation, is called natural light (unpolarized light).

Characteristics of polarized light:

One of the properties of a transverse wave is that its vibration is polar. In a plane perpendicular to the direction of propagation, it can vibrate in either direction. Generally, the direction of light wave electric field vibration is regarded as the direction of light vibration.

If a beam of light vibrates in the same direction, they are called polarized or, more strictly, fully polarized.

General natural light is evenly distributed in all directions and is unpolarized light. However, the glare formed by the reflection of a smooth non-metallic surface at an angle (called the Brewster angle, which is related to the refractive index of the substance) is polarized light. If you deviate from this angle, some unpolarized light will be mixed in with the polarized light.

We call this light partially polarized. Partially polarized light is of degree. The greater the angle of deviation, the less the components of polarized light and eventually it becomes unpolarized light.

1. Fully polarized light.

a) linearly polarized light.

The trajectory of the end point of the light vector is a straight line, that is, the light vector only vibrates in a certain direction, and its magnitude changes with the phase and the direction does not change, which is called linearly polarized light.

b) Ellipsically polarized light.

The trajectory of the end point of the light vector is an ellipse, that is, the light vector is constantly rotating, and its magnitude and direction change regularly with time.

c) Circularly polarized light.

The trajectory of the endpoint of the light vector is a circle, i.e., the light vector is constantly rotating and its magnitude does not change, but the direction changes regularly with time.

2. Partially polarized light.

In a plane perpendicular to the direction of light propagation, there are light vectors in various vibration directions, but the light vibration is more significant in one direction, and it is not difficult to see that partially polarized light is a superposition of natural light and fully polarized light.

Polarized light (polarized light), an optical noun, light is an electromagnetic wave, and electromagnetic wave is a transverse wave. The plane composed of the vibration direction and the forward direction of the light wave is called the vibration surface, and the vibration surface of light is limited to a fixed direction, which is called plane polarized light or linearly polarized light.

The asymmetry of the direction of vibration to the direction of propagation is called polarization, and it is one of the most obvious signs that distinguishes transverse waves from other longitudinal waves. Light waves are electromagnetic waves, therefore, the direction of propagation of light waves is the direction of propagation of electromagnetic waves. Both the electrical vibration vector e and the magnetic vibration vector h in the light wave are perpendicular to the propagation velocity v, so the light wave is a transverse wave and it is polarized.

Light that is polarized is called polarized light.

Normally, the vibration surface of the light emitted by a light source is not limited to a fixed direction, but is evenly distributed in all directions. This light is called natural light. The polarization of light is the most direct and powerful evidence of the transverse wave of light, and the polarization phenomenon of light can be observed with the help of experimental devices, P1 and P2 are two identical polarizers.

Natural light (such as lights or sunlight) is directly observed through a polarizer P1, and although the light passing through the polarizer becomes polarized light, it cannot be detected because the human eye does not have the ability to distinguish polarized light. If we fix the orientation of the polarizer P1 and rotate the polarizer P2 slowly, we can find that the intensity of the transmitted light changes periodically with the rotation of P2, and the luminous intensity gradually decreases from the maximum to the darkest every 90°. As p2 continues to rotate, the light intensity gradually increases from near zero to maximum.

It can be seen that the transmitted light through P1 is different from the original incident light, which indicates that the vibration of the transmitted light through P1 is not symmetrical to the propagation direction. After passing through a polarizer, natural light changes into light with a certain direction of vibration. This is due to the fact that there is a characteristic direction in the polarizer, called the polarization direction, and the polarizer only allows vibrations parallel to the polarization direction of the ridge to pass through, while absorbing light that vibrates perpendicular to that direction.

Through the transmitted light of the polarizer, its vibration limit field is controlled in a certain vibration direction, we call the first polarizer P1 polarizer, its function is to turn natural light into polarized light, but the human eye can not distinguish polarized light. It is necessary to rely on the second polarizer P2 to check. Rotate P2, when its polarization direction is parallel to the polarization plane of the polarized light, the polarized light can pass smoothly, and there is a brighter light behind P2.

When the polarization direction of P2 is perpendicular to the polarization plane of the polarized light, the polarized light cannot pass through and also darkens behind P2. The second polarizer helps us identify polarized light, so it is also called a polarizer.