As we all know, because of light, people can see this colorful world and survive in this world. Therefore, there are many light phenomena and their applications in our lives. Whether it is construction art, sculpture, painting, dance art, and many other fields, it is inseparable from the existence of light, and because of the existence of light, it is even more dazzling.

So, how does the modern day play its role in humans? And how did light develop into modern optics?

With the emergence of new technologies in the middle of the 20th century, new theories continued to develop. Due to the wide application of optics, many new branch disciplines or marginal disciplines have gradually formed. Geometric optics was originally a specialized discipline developed for the design of various optical instruments. With the advancement of science and technology, physical optics has increasingly shown its power. For example, the interference of light is still irreplaceable in precision measurement. Means, diffraction grating is an important spectroscopic instrument. Spectroscopy has played a key role in human understanding of the microstructure of matter (such as atomic structure, molecular structure, etc.). People have combined mathematics, information theory and light diffraction to develop A new subject-Fourier optics is applied to information processing, image quality evaluation, optical calculation and other technologies. In particular, the invention of lasers can be said to be a revolutionary milestone in the history of optical development. Since lasers have a series of unique properties such as high intensity, good monochromaticity, and strong directionality, they have been quickly used since it came out. Excellent results have been achieved in materials processing, precision measurement, communication, distance measurement, holographic detection, medical treatment, agriculture and other extremely wide technical fields. In addition, lasers have shown brilliant prospects for isotopic separation, storage, information processing, controlled nuclear fusion, and military applications.

Optics is a branch of physics and an ancient natural subject with a history of thousands of years of development. Around the seventeenth century, optics had initially formed an independent discipline. The particle theory represented by Newton and the corresponding geometric optics; and the wave theory represented by Huygens and the corresponding wave optics constitute the two pillars of optical theory. By the end of the nineteenth century, Maxwell geniusly summarized and expanded the knowledge of electromagnetism known at that time, and proposed Maxwell's equations, which pushed wave optics to a higher stage. However, people's further understanding of light is inseparable from the establishment of quantum mechanics and the theory of relativity. On the one hand, the optics of the nineteenth century and before provided the basis for the establishment of these two epoch-making physical theories. On the other hand, the establishment of these two theories has deepened mankind's in-depth understanding of optical phenomena. From the 17th century to the present, the development of optics has gone through five historical periods: the budding period, the geometric optics period, the wave optics period, the quantum optics period, and the modern optics period.

The modern optics period mainly began in the middle of the 20th century, which included new optical branch disciplines such as laser optics, nonlinear optics, fiber optics, thin film optics and integrated optics, information optics, Fourier transform optics, and optoelectronics. Especially after the advent of lasers, optics has entered a new era, so that it has become an important part of the frontiers of modern physics and modern science and technology. The most important achievement is the discovery of the stimulated emission of atoms and molecules predicted by Einstein in 1916, and the creation of many specific technologies for generating stimulated emission. When Einstein studied radiation, he pointed out that, under certain conditions, if the stimulated radiation can continue to excite other particles, causing a chain reaction, an avalanche-like amplification effect, and finally a very monochromatic radiation, that is, laser .

Another important branch of optics is composed of imaging optics, holography and optical information processing. This branch can be traced back to the microscope imaging theory proposed by Abbe in 1873, and the experimental verification done by Porter in 1906; Zernike proposed the contrast observation method in 1935, and the phase contrast was made by Zeiss factory accordingly. Microscope, for which he won the Nobel Prize in Physics in 1953; in 1948 Gabor proposed the predecessor of modern holography-the principle of wavefront reconstruction. For this, Gabor won the Nobel Prize in Physics in 1971.

Since the 1950s, people began to combine mathematics, electronic technology, and communication theory with optics, introducing the concepts of spectrum, spatial filtering, carrier, linear transformation and related operations to optics, updating the classic imaging optics, and forming the so-called "Fourier Optics". Coupled with the coherent light provided by the laser and the holography improved by Leith and Apate Nex, a new subject field is formed-optical information processing, that is, information optics. Information optics technology is also called optical information processing, which is the application of information optics theory to specifically solve the knowledge of receiving and transmitting, processing and confirming optical information. The characteristic of optical information processing is that it can process two-dimensional images at the same time, and the amount of processing information is extremely large, and the processing speed is also extremely fast. The Fourier transform of a photo can be completed by a computer for several hours or even longer. With an optical lens, it's done in an instant! Optical fiber communication is an important achievement based on this theory, and it provides a new technology for information transmission and processing.

In short, the combination of modern optics and other disciplines and technologies has played an increasingly important role and influence in people's production and life, providing people with a powerful scientific and technological force for understanding nature, transforming nature, and improving labor productivity.