The working substance of ruby laser is ruby rod. Shortly after the idea of laser was put forward, ruby was first used to make the world's first laser. The matrix of ruby crystal for laser is Al2O3, and about 0.05% (by weight) of Cr2O3 is doped in the crystal. The density of Cr3+ is about1.58×1019/cm3. Cr ~ (3+) replaces Al ~ (3+) in the crystal, which is uniformly distributed in it, and is optically a negative uniaxial crystal. Under the irradiation of Xe (Xenon) lamp, the particles in the ground state E 1 in ruby crystal absorbed the photons emitted by Xe lamp and were excited to E3 level. The average lifetime of E3 level particles is very short (about 10-9 seconds). Most particles reach the upper laser level E2 through non-radiative transition. The life of E2 particles is very long, reaching 3× 10-3 seconds. Therefore, a large number of particles gather in the E2 energy level, which leads to the inversion of the number of particles between E2 and E 1. At this time, the crystal can amplify photons with the frequency ν = E2-E 1 (where H is Planck constant, and E2 and E1are the energy of the upper and lower laser levels respectively), that is, light at this frequency can be obtained. When the gain g is large enough to meet the threshold condition, there is a laser output with the wavelength of 6943× 10- 10 meter at the end of some mirrors.

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The concept of stimulated radiation put forward by Einstein is an important theoretical basis. This theory points out that a matter particle in a high-energy state will be transformed into a low-energy state under the action of a photon whose energy is equal to the energy difference between two energy levels, and a second photon will be generated and emitted at the same time as the first photon, which is stimulated radiation. The light output by this radiation is amplified and coherent, that is, the emission direction, frequency, phase and polarization of multiple photons are exactly the same. Since then, the establishment and development of quantum mechanics have made people have a deeper understanding of the microstructure and motion law of matter, and the energy level distribution, transition and photon radiation of microscopic particles have also been more strongly proved, objectively perfecting Einstein's stimulated radiation theory and further laying a theoretical foundation for the generation of laser. After its birth in the late 1940s, quantum electronics was quickly applied to study the interaction between electromagnetic radiation and various micro-particle systems, and many corresponding devices were developed. The rapid development of these scientific theories and technologies has created conditions for the invention of laser. 195 1 year, American physicists purcell and Pound successfully caused the inversion of the number of particles in the experiment and obtained stimulated radiation of 50 kHz per second. Later, American physicist Charles Downes and Soviet physicists Massoff and ProHohloff successively put forward the design of generating and amplifying microwave by using the principle of atomic and molecular stimulated radiation. 1960, American physicist Theodore Mayman won the global development competition with a slight advantage in his research laboratory in Miami, Florida. He used a high-intensity flash tube to stimulate the chromium atoms in the ruby crystal, thus producing a fairly concentrated slender red beam, which can reach a higher temperature than the sun when it hits a certain point. [ 1]

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Laser generates coherent radiation (laser) by the principle of stimulated emission amplification. 1On July 7th, 960, the new york Times revealed for the first time that Maiman had successfully manufactured the world's first ruby laser. He irradiated a special ruby crystal the size of a finger with the light of a flash lamp, producing a coherent pulsed laser beam, which later shocked the world. With the efforts of the world's top laboratories to become the first person to invent the laser, Maiman's then employer, Hughes Aircraft Company of Los Angeles, won. However, when Maiman published the article, it was not smooth. He first submitted his paper to Physical Review Letters (PRL), but then editor Sam Goudsmit thought it was just another article about Maser's repeated work, so he refused to publish it. Later, Maiman finally published this article in Nature. Of course, after years of hard work, Maiman's achievements have been widely recognized. Maiman1July, 927 1 1 was born in Los Angeles, California, and is the son of an electrical engineer. Father wants him to be a doctor, but he thinks that studying laser will have a greater impact on medicine. Although Maiman was a wild child when he was a child, he was very good at mathematics. 1949 After graduating from the University of Colorado with a master's degree, Maiman went to Stanford University to study for a doctorate, and received his doctorate in 1955. His tutor is willis lamb, and 1955 won the Nobel Prize in Physics. While working at Hughes Aircraft Company, Maiman told his boss that he wanted to make a laser, but Hughes still wanted him to do some "useful" work on the computer, because other famous laboratories didn't make any exciting achievements at that time. But Maiman insisted on research and threatened to resign. In the end, the company gave him nine months, 50 thousand dollars and an assistant. After the success of the first laser, Maiman continued to study the application of laser in medical treatment, although the public at that time thought it was a "deadly" light. However, since Hughes did not invest more in the potential application of laser, Maiman chose to leave and founded his own Korad company at 196 1. [2]

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Maiman's invention has made great contributions to mankind, and laser has become an indispensable basic instrument and equipment in medicine, industry and many scientific research fields.

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Gildo H. Maiman, an American physicist and inventor of the world's first laser, died of illness at the University of British Columbia at the age of 79. Meman suffers from systemic mastocytosis, a rare genetic disease. In his life, Maiman won numerous awards. Although the 1964 Nobel Prize in Physics was not awarded to him who invented the world's first laser, it was awarded to Thomas, a Bell Laboratory physicist who invented the maser and put forward the principle and design scheme of the laser, and Basov, prokhorov and Meman, Soviet physicists, who were nominated for the Nobel Prize twice, and won the famous Japanese Prize and Wolf Prize in physics. He was also included in 1984 "National Inventors Hall of Fame". In a book commemorating the centenary of Nature magazine, Downes called Mayman's paper "the most important one" among all the wonderful papers published by the magazine in the past 100 years. Meman's commemoration will be held on May 16, because this is the day when Meman's laser first started working.