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What is the history of optics?
Optics is a discipline with a long history, which can be traced back to more than 2000 years ago.

At first, human beings mainly tried to answer the question "how can people see the objects around them?" Questions like this. About 400 BC (pre-Qin), China recorded the earliest optical knowledge in the world in Mo Jing. It has eight records about optics, describing the definition and generation of shadow, linear propagation of light and pinhole imaging, and discussing the relationship between objects and images in plane mirror, concave spherical mirror and convex spherical mirror with rigorous words.

From Mohist classics, the lens was invented by the Arabian Ibn Huysum in the 0 th century A.D.165438; From 1590 to1early 7th century, Zhan Sen and Lipski independently invented the microscope at the same time. It was not until the first half of17th century that Snell and Descartes attributed the observation results of light reflection and refraction to the reflection law and refraction law which are widely used today.

1665, Newton experimented with sunlight and decomposed it into simple components, which formed a light distribution with colors arranged in a certain order-spectrum. It makes people come into contact with the objective and quantitative characteristics of light for the first time, and the spatial separation of monochromatic light is determined by the properties of light.

Newton also found that when a convex lens with a large radius of curvature is placed on an optical flat glass, a group of colored concentric annular stripes appear at the contact between the lens and the glass plate when it is irradiated with white light; When irradiated with a monochromatic light, a group of concentric annular stripes alternating light and dark appear, which is called Newton's ring by later generations. With this phenomenon, the corresponding monochromatic light can be quantitatively characterized by the air gap thickness of the first dark ring.

When Newton discovered these important phenomena, according to the linear propagation of light, he thought that light was a particle flow. Particles fly out of the light source and move in a uniform straight line according to the laws of mechanics. Newton used this view to explain refraction and reflection.

Huygens is an opponent of the particle theory of light, and he founded the wave theory of light. It is put forward that "light, like simultaneous light, propagates through spherical wavefront". It is also pointed out that every point reached by light vibration can be regarded as the vibration center of the secondary wave, and the envelope surface of the secondary wave is the wavefront of the propagating wave. In the whole18th century, the particle flow theory of light and the wave theory of light have been put forward, but they are not complete.

/kloc-At the beginning of the 9th century, wave optics was initially formed, in which Thomas Young satisfactorily explained the phenomenon of "film color" and double-slit interference. Fresnel supplemented Huygens' principle with Young's interference principle in 18 18, thus forming Huygens-Fresnel principle which is widely known today. It can be used to satisfactorily explain the interference and diffraction of light and the straight-line propagation of light.

In the further study, the polarization of light and the interference of polarized light are observed. In order to explain these phenomena, Fresnel assumes that light is a shear wave propagating in a continuous medium (ether). In order to explain the difference of light speed in different media, it must be assumed that the characteristics of ether in different substances are different; More complex assumptions are needed in anisotropic media. In addition, it must be given more special properties to explain that light is not longitudinal wave. Ether of this nature is unimaginable.

1846, Faraday discovered that the vibration plane of light rotates in a magnetic field; 1856, Weber found that the speed of light in vacuum is equal to the ratio of electromagnetic unit to electrostatic unit of current intensity. Their findings show that there is a certain internal relationship between optical phenomena and magnetic and electrical phenomena.

1860 or so, Maxwell pointed out that the change of electric field and magnetic field cannot be confined to a certain part of space, but propagates at a speed equal to the ratio of electromagnetic unit to electrostatic unit of current, and light is such a electromagnetic phenomena. This conclusion was confirmed by Hertz experiment in 1888. However, this theory can't explain the essence of the electric oscillator that can produce such a high frequency of light, and it can't explain the dispersion phenomenon of light. It was not until 1896 that Lorenz founded the electronic theory that he explained the phenomena of light emission and absorption by matter and the various characteristics of light propagation in matter, including the explanation of dispersion. In Lorenz's theory, ether is an infinite and immovable medium, and its only feature is that the vibration of light has a certain propagation speed in this medium.

Lorenz theory can not give a satisfactory explanation for such an important problem as the distribution of energy by wavelength in hot blackbody radiation. Moreover, if Lorenz's concept of ether is correct, we can choose a fixed ether as the frame of reference, so that people can distinguish absolute motion. In fact, in 1887, Michelson measured the "etheric wind" with an interferometer and got a negative result, which shows that people still have a lot of one-sided understanding of the nature of light during Lorenz's electronic theory period.

1900, Planck borrowed the concept of discontinuity from the molecular structure theory of matter and put forward the quantum theory of radiation. He believes that electromagnetic waves of various frequencies, including light, can only be emitted from the vibrator with the energy of its own determined composition. This kind of energy particle is called quantum, and the quantum of light is called photon.

Quantum theory not only naturally explains the law of radiation energy distribution according to wavelength, but also puts forward the whole problem of interaction between light and matter in a brand-new way. Quantum theory not only provides a new concept to optics, but also to the whole physics, so its birth is usually regarded as the starting point of modern physics.

1905, Einstein explained the photoelectric effect with quantum theory. He made a very clear statement about photons, especially pointing out that when light interacts with matter, light also takes photons as the smallest unit.

1905 In September, the German Yearbook of Physics published Einstein's article "Electrodynamics of Moving Media". The basic principle of special relativity was put forward for the first time. It is pointed out that the application scope of classical physics, which has been dominant since Galileo and Newton's time, is limited to the case that the speed is much less than the speed of light, and his new theory can explain the characteristics of processes related to high-speed motion, completely giving up the concept of ether and satisfactorily explaining the optical phenomenon of moving objects.

In this way, at the beginning of the 20th century, on the one hand, the interference, diffraction and polarization of light and the optical phenomena of moving objects confirmed that light is electromagnetic wave; On the other hand, the quantum nature of light-particle nature, has been undoubtedly proved from the aspects of thermal radiation, photoelectric effect, light pressure and chemical action of light.

The Compton effect discovered in 1922, the Raman effect discovered in 1928, and the ultra-fine structure of atomic spectrum obtained by experiments at that time all indicate that the development of optics is closely related to quantum physics. The development history of optics shows that the two most important basic theories in modern physics, quantum mechanics and special relativity, were born and developed in the study of light.

Since then, optics has entered a new era, making it an important part of the frontier of modern physics and modern science and technology. One of the most important achievements is the discovery of atomic and molecular stimulated radiation predicted by Einstein in 19 16, and the creation of many specific technologies to produce stimulated radiation.

When studying radiation, Einstein pointed out that under certain conditions, if stimulated radiation can continue to excite other particles, causing a chain reaction and obtaining an avalanche-like amplification effect, it will eventually obtain monochromatic radiation, that is, laser. 1960, Mei? a target = _ blank href =/view/30524 . htm & gt。 Ruby made the first visible laser; In the same year, he-ne laser was manufactured; 1962 produced a semiconductor laser; 1963 produced a tunable dye laser. Laser has been rapidly developed and widely used since its discovery in 1958 because of its good monochromaticity, high brightness and good directivity, which has caused great changes in science and technology.

Another important branch of optics is imaging optics, holography and optical information processing. This branch can be traced back to the microscopic imaging theory put forward by Abbe in 1873 and the experimental verification completed by Porter in 1906. 1935, Zelnik put forward the phase contrast observation method, and made a phase contrast microscope by Zeiss factory, for which he won the 1953 Nobel Prize in physics. 1948, dennis gabor put forward the principle of wavefront reconstruction, the predecessor of modern holography, for which dennis gabor won the 197 1 Nobel Prize in physics.