What is Faraday's rotator?
Faraday Rotator is a device without moving parts that change the angle of polarization or the angle of wool, the light passing through it. Light passes through air or other materials such as a number of waves, called electromagnetic radiation, with the properties of electrical and magnetic fields. The device works on the principle that the light passing through the crystal or a solid transparent material changes the polarization if the magnetic field is present.
discovered by scientist Michael Faraday in 1845 was the effect of magnetic fields on the waves of light the first proof that light is an electromagnetic wave. He found that the change in magnetic field strength was influenced by the angle of light polarization. He named Faraday Effect, this is the basis of a rotator that uses an experimental effect in a practical device.
The light passing through many materials, including glass and water, can be affected by the polarization angle without the use of magnetic fields. This effect is caoptical polarization and sunglasses manufacturers use it by using the lensy that block polarized angles other than normal light. The effect of the glare is reduced because the discouraged light from the water or buildings will have a different angle of polarization.
To form a Faraday rotator, the magnet surrounds the transparent material. When light passes through, the magnetic field causes the light wave to turn into a specific amount. The amount of rotation can be determined by an equation that uses the magnetic field, the length of the crystal and the verdet constant of the material. This constant varies for all materials and temperature changes; The constants tables are published for materials at different temperatures.
Laser devices often use Faraday Rotator as a protective device to prevent reflected laser energy into the unit. When the laser crey to a beam of light is very coherent, which means it contains the light of one specific wave. As the light leaves the laser, often reflects or pThere are other equipment and potentially some light could bounce back into the laser. Adding the Faraday rotator prevents this from this, because the light passing by the rotator is usually polarized 45 ° from the original beam and cannot bounce back. The angle can be changed, but more polarization requires additional magnetic field strength.
Another advantage of Faraday's rotator is that through the light passing and then returns in the opposite direction, it is not turned backwards. If the rotator is polarized 45 ° and then intervenes the mirror and returns, the rotator polarizes another 45 °. This effect can be used by optical polarization filters or devices that create specific polarization levels for laboratory use. This works by reflecting some light back through the Rotanebo creation of two light beams that are polarized at different angles.