Light is everywhere, this is not exaggerated. In the early days of human development, humans have begun to use light to transmit information. There are many examples.
Gesturing is a form of visual communication that cannot be performed in the dark. During the day, the sun serves as the light source for this transmission system. The solar radiation carries the information of the sender to the receiver, the movement of the hand modulates the light waves, and the human eye acts as a detector. In addition, beacon towers that existed more than 3,000 years ago can still be regarded as the original form of optical communication. The emergence of the telescope has greatly extended the distance of this type of visual optical communication.
One day in 1870, British physicist Tyndall went to the lecture hall of the Royal Society to talk about the principle of total reflection of light. He did a simple experiment: drill a hole in a wooden bucket filled with water, and then use a lamp to pull Water illuminates. The results surprised the audience. People saw that the shining water flowed out of the small holes in the bucket, the water flow was curved, and the light followed it, and the light was captured by the curved water.
These phenomena attracted Ding Daer’s attention. After his research, he found that this is the effect of total reflection, that is, when the light is incident from the water to the air, when the incident angle is greater than a certain angle, the refracted light disappears, and all the light is reflected back into the water. On the surface, light seems to bend in the current. In fact, in a curved stream of water, light still travels in a straight line, but multiple total reflections occur on the inner surface, and the light propagates forward after multiple total reflections.
Later, people created a kind of glass fiber with high transparency and thickness like spider silk. When the light enters the glass fiber at an appropriate angle, the light advances along the curved glass fiber. Because this fiber can be used to transmit light, it is called an optical fiber.