Text | China Science News reporter Wang Zhaoyu
In September 1961, a bright orange-red light emanated from Changchun, Jilin Province, illuminating the history of lasers in China. This beam of light is emitted from China's first ruby laser, which was developed by optical scientists and academicians of the Chinese Academy of Sciences, Wang Zhijiang and Deng Ximing.
This ruby laser is no small one. It was born in the Institute of Optics and Fine Mechanics of the Chinese Academy of Sciences (one of the predecessors of the Changchun Institute of Optics, Fine Mechanics and Physics of the Chinese Academy of Sciences (hereinafter referred to as the Changchun Institute of Optics and Mechanics), only one year later than the United States physicist Theodore · Mehmann developed the world's first laser, using an unprecedented innovative design, with better performance and higher efficiency.
This is the "light" that belongs to China, and it embodies all the efforts of scientific researchers. Under the conditions of economic difficulties and weak industrial foundation at that time, it was not easy for Changchun Optical Machinery to successfully develop a ruby laser in a relatively short period of time and create a miracle of "China's first" and "world's second".
The first ruby laser in China.
An "epoch-making" invention
Laser, is another major invention since the 20th century after atomic energy, computers and semiconductors, because of its unique properties are widely used in many fields, such as laser myopia surgery and other high-precision, minimally invasive treatment methods in medicine, laser marking, cutting and welding in the manufacturing industry, laser fiber communication technology in the field of communications, as well as laser guided weapons, lidar and laser defense systems in national defense, known as "the brightest light", "the most accurate ruler" and "the fastest knife".
Regarding the significance of laser in the history of human science and technology development, Wang Zhijiang once commented: "In the 100 years of the 20th century, the development of optics has experienced a veritable leap, in which the invention of laser has played an epoch-making role. ”
It is not easy to obtain such an important laser because it is not the light emitted by nature, but the light amplified by "stimulated radiation". The theoretical basis of lasers is the theory of "stimulated radiation" proposed by Albert Einstein in 1917, that is, atoms can emit light when excited by external energy, and this light is coherent.
In 1958, United States physicists Charles · Townes and Arthur · Shore jointly published a paper "Infrared and Optical Quantum Amplifier" in Physical Review, proposing the concept of the first practical laser and predicting the feasibility of lasers.
After the publication of the paper, the global competition was fierce, and research groups in many countries tried to be the first to make a laser.
Under the crowd of heroes, Chinese scientists are not willing to be left behind. At that time, a group of young researchers such as Wang Zhijiang, Wang Naihong, and Gu Quwu of Changchun Institute of Optics and Mechanics had realized that several laws of classical optics seriously limited the application of optical technology, and produced innovative physical ideas that broke the laws of classical optics and reformed the light source. These ideas coincide with the conclusions of the research in "Infrared and Optical Quantum Amplifiers".
After reading the papers of Townes and Xiao Luo, Wang Zhijiang and others immediately understood its essence. They realized that the birth of the light maser (later known as the laser) was of epoch-making revolutionary significance—the limitations of several laws of classical optics were broken, and the generation and application of coherent light waves also had broad prospects. They immediately decided to explore lasers as an important new area of research.
However, at that time, China had almost no communication with developed countries such as Britain and the United States, and could only learn about the world's scientific and technological frontiers through some foreign academic publications. Huang Wuhan of the Institute of Electronics of the Chinese Academy of Sciences learned about the research information of foreign microwave quantum amplifiers, and took the lead in the development of ruby microwave quantum amplifiers in China, and made 10 cm band and 3 cm band quantum amplifiers at the temperature of liquid nitrogen at the end of 1959.
Inspired by Huang's achievements, Wang Zhijiang, Deng Ximing and others began to develop optical quantum amplifiers, but this was not their main work at that time. So, in their prime, they used their spare time to conduct spontaneous research without financial support.
In May 1960, Mehmann built the world's first laser at Bell Labs in United States. Once the results were released, they attracted the attention of the world and gave great encouragement to the researchers of Changchun Institute of Optics and Mechanics. Because at that time, many scientists in the world felt that gaseous substances should be used as the excitation medium, and the ruby laser made by Mehman showed everyone the feasibility of using ruby as an excitation medium.
Meyman invents the world's first ruby laser.
Jin Hong, Secretary of the Party Group and President of the Changchun Branch of the Chinese Academy of Sciences, said: "After the first laser appeared, Wang Zhijiang and others wrote a letter to the leaders of the institute, and their work was highly valued and strongly supported by Wang Daheng, the director at the time. At the end of 1960, Wang Zhijiang and others quickly formulated an experimental plan for generating infrared lasers, which shows their scientific skills and deep grasp of this problem. This handwritten plan is still preserved in the library of the Changchun Institute of Optics and Mechanics. ”
Work hard and forge ahead
To make a ruby laser as soon as possible was both a rare opportunity and a difficult challenge for the researchers of Changchun Institute of Optics and Mechanics at that time.
Due to the weak industrial base of New China, there are very few ready-made materials that can be provided in China. For example, at that time, pulsed xenon lamps, which were easily available in foreign markets, but there were no manufacturers that could produce them in China, so Wang Zhijiang and others could only design and manufacture the pulsed xenon lamps required for ruby lasers from scratch. For another example, at that time, there was a large gap between the quality of domestic rubies and foreign rubies in terms of uniformity, transmittance, scattering particles, etc., which could not meet the optical requirements, and researchers needed to further improve the technology.
In addition, the researchers of Changchun Institute of Optics and Mechanics have no background in radio disciplines and are not familiar with the theory of resonators, so they need to learn from scratch when designing resonators.
Instrument Museum of the Chinese Academy of Sciences (former site of Changchun Institute of Optics and Mechanics).
Deng Ximing, then deputy director of the research department of the Changchun Institute of Optics and Mechanics, described the conditions for the development of lasers as follows: "Although it was not the first time we tried it in the world, we had only seen one or two news reports at that time, except for one or two articles on principle. It is not easy to turn a completely new idea into reality on the basis of our own experimental techniques. ”
Deng Ximing, who was 30 years old at the time, had been working at Changchun Institute of Optics and Mechanics for eight years, and he was determined to make China's own laser. Therefore, he used his spare time to learn a lot of laser-related knowledge, regardless of cold and summer, forgetting to sleep and eat, and organized and participated in the research of China's first laser with Wang Zhijiang. After graduating from university in 1952, Deng Ximing was determined to devote his life to optical research.
Wang Zhijiang, who was born in the same year as Deng Ximing, also came to work at Changchun Institute of Optics and Mechanics in 1952 and participated in the establishment of the Instrument Museum of the Chinese Academy of Sciences (one of the predecessors of Changchun Institute of Optics and Mechanics). They have witnessed the spirit of hard work and entrepreneurship of the older generation of scientists, and they have also brought this spirit to their work.
Before leading the development of ruby lasers, Wang Zhijiang had completed the design of a large number of optical instruments urgently needed by the country, and opened two optical design training courses from 1958 to 1959, cultivating a large number of optical talents for China. And he himself has accumulated a wealth of leadership and practical experience.
Wang Zhijiang and Deng Ximing led the team to carry out three structural technological innovations in the development of ruby lasers, namely a straight tubular pulsed xenon lamp, a spherical imaging illuminator and a resonator with a focusing device. These innovations made the ruby laser developed by Continental more efficient than the United States one, and the related process has been used in the laser field for decades.
The first is the design of a straight tubular pulsed xenon lamp. The ruby laser manufactured by Mayman uses a spiral xenon lamp, and Wang Zhijiang et al. improved the xenon lamp according to the optical laws they had mastered when redesigning it. "The spiral xenon lamp used abroad is actually not scientific, and we found that the useful size of the lamp cannot exceed the gem rod, so we made a straight tubular pulsed xenon lamp." Wang Zhijiang said.
In the process of making xenon lamps, researchers also encountered the sealing problems between the tungsten electrode and quartz of xenon lamps and the supply of xenon. Du Jilu, a technician of Changchun Institute of Optics and Mechanics, has blown more than 20 kinds of transition glass with superb skills to complete the sealing of tungsten electrode pulsed xenon lamps on the wall of high-power quartz tubes, and the process he founded has been used in the domestic laser field for decades. The bottles of xenon used in the xenon lamp were found in the warehouse of an unknown light bulb factory by a buyer who traveled half of China before the liberation.
The second is to design the spherical image illuminator. At that time, Meiman's elliptical diffuse illuminator was once very popular abroad, but Wang Zhijiang learned from the analysis of the basic principles of optics that the spherical illumination system was more efficient than the elliptical illumination system, and the imaging illumination was also more efficient than the diffuse illumination. China was the first country in the world to adopt a spherical imaging illuminator, and the excitation efficiency of this design is higher than that of Mehman.
Finally, there is a resonator with a focusing device, which is an innovation for the defects of domestic ruby crystals. Researchers from Changchun Institute of Optics and Mechanics first learned the theory of parallel plate reflection resonator of Towns and Xiao Luo, but in subsequent tests, it was found that the defects of domestic rubies led to a large error in the estimation of the number of waveforms in the resonator, so the gemstone was processed into an irregular shape with two sides that were not parallel to each other, and the cold cathode sputtering method was used to make one end of the gem rod fully silver-plated, and the transmittance of the silver-plated surface at the other end was between 2% and 15%.
In September 1961, China's first ruby laser was born and successfully achieved laser output. This is truly "China's first" and "world's second" - just over a year later than United States and two months before the first Soviet Union.
When Wang Zhijiang talked about the development of this ruby laser, he attributed the reasons for its success to three points: the early development of Changchun Institute of Optics and Mechanics laid the required technical foundation; The rapid improvement of the academic level of young scientific and technological talents has laid the required talent foundation; The integration of the inspiration of foreign research and the innovative spirit of Chinese scholars has accelerated the research process.
Instrument Museum of the Chinese Academy of Sciences (former site of Changchun Institute of Optics and Mechanics).
China's "light" is thriving
The birth of ruby laser is of great significance to the field of science and technology in mainland China. The Chronicle of the Chinese Academy of Sciences commented: "Its successful development has opened up a completely new field of research in China." ”
The significance of ruby lasers to economic development should not be underestimated. Jin Hong pointed out: "As an important supporting technology, since the successful development of ruby lasers, various lasers such as gas lasers, semiconductor lasers, chemical lasers, solid-state lasers and related technologies have sprung up like mushrooms after a rain. After years of development, the laser industry has become an extremely important part of the national economy. ”
With the application and rapid development of international and domestic laser technology, in May 1964, the Shanghai Branch of the Institute of Optics and Fine Mechanics of the Chinese Academy of Sciences (the predecessor of the Shanghai Institute of Optics and Fine Mechanics of the Chinese Academy of Sciences (hereinafter referred to as the Shanghai Institute of Optics and Mechanics) was established. The Shanghai Institute of Optics and Mechanics was the world's first research institute specializing in laser research, and since then, China's laser industry has "branched out".
Instrument Museum of the Chinese Academy of Sciences (former site of Changchun Institute of Optics and Mechanics).
And Wang Zhijiang also continues to contribute to the laser industry with his keen scientific sense. He has always stood at the forefront of laser science and technology, closely watched the latest developments in the development of laser science and technology in the world, organized forces to track and catch up in a timely manner, and strived to make the mainland's research level in laser science and technology keep up with the trend of international development.
After the establishment of the Shanghai Institute of Optics and Mechanics, Wang Zhijiang served as the director of the solid-state laser research office of the institute, carrying out research on laser physics, laser unit technology and overall device. He and his colleagues selected neodymium glass as an important working substance to increase its output power by improving efficiency and scale-up; Directivity is improved through a variety of measures to make it a high-brightness device. The neodymium glass laser they tried to produce has reached the international advanced level.
Deng Ximing led the research on laser nuclear fusion, developed and developed high-power laser drivers, built the largest "Shenguang" laser device in the mainland, and used the Shenguang device to achieve a series of major research results in high-tech frontier fields such as inertial confinement fusion and X-ray laser.
Time flies, and quietly, China's "light" is thriving. In 2005, the International Commission on Optics (ICO) Academic Conference was held in China for the first time. At that time, Wang Daheng, the former director of Changchun Institute of Optics and Mechanics, was 92 years old, and Tang Si, who was invited to Changchun to attend the meeting, was also 92 years old. Two veteran scientists spanning the centuries have witnessed a new era of mankind opened by lasers.
Jin Hong recalled: "At that ICO conference, both old men gave academic reports for nearly two hours. Townes looked at our first laser in China and was very appreciative of it, saying, 'Yours is much more efficient than Mayman's.'" ”
Mr. and Mrs. Townes (1st and 2nd from left) visit Changchun Institute of Optics and Mechanics.
Opening Ceremony of the 2005 International Commission on Optics. In addition to the signature, the picture is provided by Changchun Optical Machinery Institute
It is the bright beam of light emitted by the ruby laser born in the Chinese Academy of Sciences many years ago that illuminates the development of China's laser industry and the way forward for researchers. Jin Hong commented: "In the initial stage, the mainland's laser technology developed rapidly, both in quantity and quality, and was close to the international level at that time. It is rare for an innovative technology to enter the world's advanced ranks so quickly in the history of modern scientific and technological development on the mainland. ”
The vigorous development of China's laser industry is the crystallization of the silent work of generations of scientists and engineers. They shoulder the mission of the times, dare to innovate and explore, and turn the brilliant achievements of laser technology into a symbol of national strength.
Today's China is at the forefront of scientific and technological innovation. Ruby lasers "inspire" the light of China and illuminate the glorious journey of the "Chinese Dream".