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专业英语6_LasernullnullnullnullLaser AdventureLaser Adventurenull激光物理介绍: 激光最初称作“镭射” ,是其英文LASER的音译。它基于爱因斯坦在1916年提出的一套全新理论,该理论是说在组成物质的原子中,有不同数量的粒子(电子)分布在不同的能级上,在高能级上的粒子受到某种光子的激发,会从高能级跳到(跃迁)到低能级上,这时将会辐射出与激发它的光相同性质的光,而且在某种状态下,能出现一个弱光激发出一个强光的现象。这就叫做“受激辐射的光放大”,简称激光。 1950年,波...

专业英语6_Laser
nullnullnullnullLaser AdventureLaser Adventurenull激光物理介绍: 激光最初称作“镭射” ,是其英文LASER的音译。它基于爱因斯坦在1916年提出的一套全新理论,该理论是说在组成物质的原子中,有不同数量的粒子(电子)分布在不同的能级上,在高能级上的粒子受到某种光子的激发,会从高能级跳到(跃迁)到低能级上,这时将会辐射出与激发它的光相同性质的光,而且在某种状态下,能出现一个弱光激发出一个强光的现象。这就叫做“受激辐射的光放大”,简称激光。 1950年,波尔多一所中学的教师阿尔弗雷德·卡斯特勒与让·布罗塞尔发明了“光泵激”技术。这一发明后来被用来发射激光,并使他在1966年获得了诺贝尔物理学奖。 null 1960年7月,美国加利福尼亚州休斯航空公司 实验室 17025实验室iso17025实验室认可实验室检查项目微生物实验室标识重点实验室计划 的研究员梅曼在加利福尼亚的休斯空军试验室进行了人造激光的第一次试验,第一束人造激光产生了。这束仅持续了3亿分之一秒的红色激光标志着人类文明史上一个新时刻的来临。世界上第一台激光器——红宝石激光器诞生,它是一种固体激光器。在梅曼成功之后不久,贝尔实验室的氦氖激光器也试验成功。 自1960年以来,激光家族有着迅猛的增长。现在有不同形状不同大小的各式激光器,可产生出不同功率、不同波长的激光。这些激光的范围包含从红外到紫外以至X射线的所有区域。激光的发现大大鼓舞了光通信的研究工作,为科研工作者开创了意想不到的前景和研究领域,可以说没有激光的发明就不会有今天的光通信或光纤通信。 null娱乐激光介绍: 激光技术被用于娱乐业也已有很长历史。20 多年前,欧美等国的视觉 设计 领导形象设计圆作业设计ao工艺污水处理厂设计附属工程施工组织设计清扫机器人结构设计 技术人员开始发掘激光在娱乐领域的应用潜力。人们发现激光的物理学特性决定了其亮度高,成型效果好,颜色鲜艳等其他常规灯光所无法比拟的优势,于是人们开始尝试在舞台设计上使用激光,其不可抗拒的魅力马上使设计师们爱不释手。随着激光应用越来越广泛,在国外也陆续出现了一些专门从事此项技术的机构和工作室等,更出现了一些著名的激光艺术家。混合气体激光器的诞生为娱乐激光技术带来的飞跃性发展,激光的色彩从单一的绿、红等发展成为白色光,通过对白色激光的进一步加工和提取,人们可根据需要同时获得各种颜色的彩色光。 nullnull 随着激光技术的进一步发展及其他周边设备和技术的进一步成熟,更多的激光艺术形式也慢慢浮出水面,一些艺术家们开始在环境设计领域内使用激光。水幕的出现使激光在人造景观方面更是大显身手。在传统的灯光喷泉等水艺术形式已经越来越被人们所熟悉和厌倦了之后,水幕激光使得众多的艺术家们找到了一种全新的、更有力的体现自己的设计理念的工具。很多应用了激光技术的人造景观频频获得设计大奖。 其他的应用形式如楼梯装饰,户外广告,以及探照灯等应用方式也开始活跃起来。各国的激光艺术家们正在努力发掘激光的艺术内涵和潜力,他们相信通过激光的独特魅力,能塑造出更多的惊世之作。 null济南泉城广场激光音乐喷泉工程,造价822万元,国家鲁班奖What is a LaserWhat is a Laser Most people know the word laser, but do they know what it really is? What‘s the difference between ordinary light and laser and what does laser really stand for? Let’s start with the last question. Laser is an acronym [‘krnim](只取首字母的缩写词), that is a word made up of initial letters(词首字母). The complete name is light amplification[,mplifi’ kein](扩大) by stimulated emission of radiation(受激辐射的光放大). Almost everyone knows that the police use laser when they measure speed, but how many know that you also use laser several times during an ordinary day? nullYou'll find it in CD players, laser printers and much, much more. You often find laser in action movies where the hero has to escape the laser beams when he's trying to solve a thrilling problem. The power contained in laser is both fascinating and frightening. 1. How Does Laser Light Differ from Other Light ?1. How Does Laser Light Differ from Other Light ?null “Ordinary light” (from the sun or lamps) is composed of many different wavelengths, radiating in all directions, and there is no phase(相位) relation between the different waves out of the source. Laser radiation is characterized by(…的特点是) certain properties which are not present in other electromagnetic radiation: Monochromaticity [,mn,krm’tisiti](单色性), Directionality [di,rekn’nliti] and Coherence [k’hirns](相干性). Monochromaticity Monochromaticity means “One color”. White light contains all the colors in the spectrum(光谱), but even a colored light, such as a red LED (light emitting diode[‘daid]二极管) contains a continuous interval of red wavelengths.nullnull In the theoretical sense “One Color”, which is called “spectral line”, means one wavelength (0). A graph of light intensity(光强度) versus [‘v:ss](对(指诉讼,比赛等中)) wavelength for ideal “one color” is shown on the right figure. The left figure shows a description of realistic (实际的) “one color”. It has a peak of its value of “the color”, but include a spread around the central peak. In reality, every spectral line has a finite [‘fainait](有限的) spectral width () around its central wavelength (0). null directionality [di,rekn’nliti](方向性, 定向性) Radiation comes out of the laser in a certain direction, and spreads at a defined divergence angle ()(扩散角). This angular spreading of a laser beam is very small compared to other sources of electromagnetic radiation, and described by a small divergence angle (of the order of milli-radians). In this figure, a comparison is made between the radiation out of a laser, and the radiation out of a standard lamp. Since laser radiation divergence is of the order of milli-radians, the beam is almost parallel [‘prlel](平行的), and laser radiation can be sent over long distances. null从星火光程实验室射向空中一点处的三条绿色激光束。 A laser with beam divergence of 1 milli-radian creates a spot of about 10 [mm] at a distance of 10[m]. nullThe laser power measured over a defined unit surface area is called Power Density. Now we calculate the power density of radiation at a distance of 2 meters, from an incandescent [,inkn’desnt] lamp(白炽灯) rated 100 [W], compared to a helium [‘hi:ljm] -neon[’ni:n] laser(氦氖激光) of 1 [mW]. The laser beam diameter [dai’mit](直径) at the laser output is 2 [mm], and its divergence is 1 [mrad]. When calculating radiation power in the visible spectrum, the low efficiency of the incandescent lamp must be considered (A 100 [W] lamp emits only 1-3 [W] of visible radiation, and all the rest is in the infrared [‘infr’red](红外的) spectrum). null At a distance of 2 [m] from the radiation source, the power density of the laser radiation is 40 times higher than from the lamp, although the power from the lamp is 105 times the power of the laser. This is the reason why a 1 [mW] laser radiation is considered dangerous, and the light out of a 100 [W] incandescent lamp is not!!! The laser can also be focused to very small diameters where the concentration of light energy becomes so great that you can cut or drill with the beam. It also makes it possible to illuminate and examine very tiny details. It is this property that is used in surgical [,s:dikl](外科的) appliances(器械) and in CD players. null Coherence [k’hirns](相干性) Coherence is a complicated subject, and is used in special applications of the laser, like interference [,int’firns](干涉) and holography [h’lgrfi](全息摄影术). Every electromagnetic wave can be described as a superposition [,sju:pp’zin](叠加) of sine waves(正弦波) as a function of time. Coherent waves are waves thatmaintain the relative phase between them. This figure describes, 3 waves marked y1, y2, y3, and their superposition. In figure a, the waves are coherent, like the waves out of a laser. 2. What is Stimulated Emission ?2. What is Stimulated Emission ?null To explain how the laser has these characteristics , we need to understand the basic physical principles of the operation of a laser. In principle(原则上), the laser is a device which transforms energy from other forms into electromagnetic radiation. The energy put into the laser can be in any form such as: electromagnetic radiation, electrical energy, chemical energy, etc. This is a very general definition, but it helps to understand the basic physics of the laser. We will try to obtain a qualitative [‘kwlittiv](定性的) picture of the quantum nature of the laser, based on some basic principles which came from the advanced mathematical tools (A Full explanation of laser action requires advanced courses in physics, like "Quantum Electrodynamics", and sophisticated mathematical tools). null As a basis for understanding lasing processes, a few subjects in physics are needed: 1. Basic elements of the structure of matter - the atom. 2. Wave theory - especially electromagnetic waves. 3. The interaction of electromagnetic radiation with matter. Bohr model of the atomnull Energy transfer to and from the atom Energy transfer to and from the atom can be performed in two different ways: 1. Collisions with other atoms, and the transfer of kinetic [kai’netik] energy(动能) as a result of the collision. This kinetic energy is transferred into internal energy(内能) of the atom. 2. Absorption and emission of electromagnetic radiation. Since we are now interested in the lasing process, we shall concentrate on the second mechanism [‘meknizm](机制) of energy transfer to and from the atom (The first excitation mechanism is used in certain lasers, like Helium-Neon, as a way to put energy into the laser). null Absorption of electromagnetic Radiation The process of photon absorption by the atom is a process of raising the atom from a lower energy level into a higher energy level (excited state), by an amount of energy which is equivalent to the energy of the absorbed photon. Our discussion involved a microscopic [maikr’skpik](微观的) system in which one photon interacts with one atom. In a macroscopic [,mkr’skpik](宏观的) system, when electromagnetic radiation passes through matter, part of it is transmitted, and part is absorbed by the atoms. The intensity (I) of the transmitted radiation(穿透辐射) through a thickness (x) of homogeneous [,hm’di:njs](均匀的) material, is described by the experimental equation of exponential [,eksp’nenl](指数的) absorption: I=I0exp(-x)nullI0 = Intensity of incoming radiation.  = Absorption coefficient [ki’fint](吸收系数) of the material. The transmission (T) of this material is described by the relation between the transmitted intensity (I) to the incident(入射的) intensity (I0): T=I/I0. From the last two equations we get the Transmission: T = exp(-x). Every material is transparent [trns’prnt](透明的) differently to different wavelengths, so the absorption coefficient is  function of the wavelength: (I), which is characteristic of each material. This fact is very important to understand the interaction of electromagnetic radiation with matter, in the variety [v’raiti] of applications of the laser. nullnull Spontaneous [spn’teinjs] emission(自发发射) of electromagnetic Radiation One of the basic physical principles is that: Every system in nature "prefers" to be in the lowest energy state. This state is called the Ground state. When energy is applied to a system, the atoms(electrons) in the material are excited, and raised to a higher energy level. These electrons will remain in the excited state for a certain period of time, and then will return to lower energy states while emitting energy in the exact amount of the difference between the energy levels(E). The emission of the individual photon is random, being done individually by each excited atom, with no relation to photons emitted by other atoms. When photons are randomly emitted from different atoms at different times, the process is called Spontaneous Emission. null1.基态能级上的粒子   2.粒子被激发到E2能级上 1.处于高能级E2上的粒子   2.粒子跃迁到低能级E1上, 同时发射出一个光子 null Thermodynamic [‘:mdai’nmik] Equilibrium [,i:kwi’librim](热力学平衡) From thermodynamics we know that a collection of atoms, at a temperature T, in thermodynamic equilibrium with its surrounding, is distributed so that at each energy level there is on the average a certain number of atoms. The number of atoms (Ni) at specific energy level (Ei) is called Population Number(特定能级中的粒子总数). The Boltzmann equation determines the relation between the population number of a specific energy level and the temperature: Ni = const * exp (-Ei/kT) The Boltzmann equation shows the dependence of the population number (Ni) on the energy level (Ei) at a temperature T. From this equation we see that: 1. The higher the temperature, the higher the population number. 2. The higher the energy level, the lower the population number.null Relative Population (N2/N1) The relative population (N2/N1) of two energy levels E2 compared to E1 is: N2/N1 = exp[-(E2-E1)/kT]. Conclusions: The relation between two population numbers (N2/N1) does not depend on the values of the energy levels, but only on the difference between them. For a certain energy difference, the higher the temperature, the bigger the relative population.null The difference between population numbers In a thermodynamic equilibrium, the population number of higher energy level is always less than the population number of a lower energy level. The lower the energy difference between the energy levels, the less is the difference between the population numbers of these two levels. Physically, the electrons inside the atom prefer to be at the lowest energy level possible. Population Inversion [in’v:n](粒子数反转) We saw that in a thermodynamic equilibrium Bolzmann equation shows us that : N1 > N2 > N3. This situation is called “Normal Population”. In a situation of normal population a photon impinging on(撞击) the material will be absorbed, and raise an atom to a higher level. null By putting energy into a system of atoms, we can achieve a situation of “Population Inversion[in’v:n]“(粒子数反转). In population inversion, at least one of the higher energy levels has more atoms than a lower energy level. An example is described in Figure b. null Stimulated Emission Atoms stay in an excited level only for a short time (about 10-8 s), and then they return to a lower energy level by spontaneous emission. Every energy level has a characteristic average lifetime, which is the time after which only 1/e (about 37%) of the excited atoms still remain in the excited state. Thus, this is the time in which 63% of the excited atoms returned to a lower energy level. According to the quantum theory, the transition(跃迁) from one energy level to another is described by statistical probability(统计概率). The probability of transition from higher energy level to a lower one is inversely proportional[pr’p:nl] (成反比) to the lifetime of the higher energy level. null When the transition probability is low for a specific transition, the lifetime of this energy level is longer (about 10-3 s), and this level becomes a “meta-stable” level(亚稳能级). In this meta-stable level a large population of atoms can assembled. As we shall see, this level can be a candidate for lasing process. When the population number of a higher energy level is bigger than the population number of a lower energy level, a condition of "population inversion" is established. null If a population inversion exists between two energy levels, the probability is high that an incoming photon will stimulate an excited atom to return to a lower state, while emitting another photon of light. The probability for this process depend on the match between the energy of the incoming photon and the energy difference between these two levels.  The definitions of “lifetime” of an energy level, decay of excited energy levels and absorption, are connected to the subject of “statistical mechanics“(统计力学) and the Heisenberg uncertainty principle from "quantum mechanics". Properties of Laser Radiation: The photon which is emitted in the stimulated emission process is identical to the incoming photon. They both have:null Remember that two photons with the same wavelength (frequency) have the same energy: E = hn = hc/l. The incoming photon does not change at all as a result of the stimulated emission process. As a result of the stimulated emission process, we have two identical photons created from one photon and one excited state. Thus we have amplification in the sense that the number of photons has increased. 1. Identical wavelengths -Monochromaticity.  2. Identical directions in space -Directionality.  3. Identical phase -Coherence. These are the properties of laser radiation.nullThis is the process that was explained in the introduction: Light Amplification by Stimulated emission of Radiation = LASER For more advanced comment, the incoming photon is an electromagnetic field which is oscillating in time and space. This field forces the excited atom to oscillate with the same frequency and phase as the applied force.1.处于高能级E2上的粒子。  2.粒子跃迁到低能级E1上,同时发射出一个光子。 受激辐射时光束放大null光与物质作用有三方面:  (1)受激吸收:低能级E1的粒子当吸收一定频率的外来光能时,粒子的能量就会增到E2,从低能级跃迁到高能级,这一过程叫做受激吸收;而外来光的能量被吸收,使光减弱。粒子进行跃迁不是自发的,要靠外来光子刺激而进行。粒子是否能吸收发来的光子,还得取决于两个能级性质和趋近于粒子的光子数的多少有关,而与方向、位相等方面无关。null(2)自发辐射:处于高能级的粒子很不稳定,会迅速跃迁到低能级上,同时以光子的形式放出能量。这一过程不受到外界作用时完全是自发的,所产生的光没有相位和方向都不一致,不是单色光,叫做自发辐射跃迁。可是在跃迁过程中有一些不产生光辐射的跃迁,它们主要是以热运动形式消耗能量,即无辐射跃迁。自发辐射的特点,即每一个粒子的跃迁都是自发地、孤立地进行,相互独立,彼此无联系。产生的光子杂乱无章,无规律性。 (3)受激辐射:它是与受激吸收相反的过程。处于高能级的粒子,在某种频率光子诱发下,从原来所在的高能级跃迁到低能级,放出与外来光子完全相同光子,此时既产生了一个光子(受激发前后共有2个光子)。这一过程称做受激辐射。受激辐射的特点是,本身不是自发辐射,而是受外来光子的刺激产生。因而释放出的光子与原来光子的频率、方向传播、相位及偏振等完全一样,无法区别出哪一个是原来的光子,哪一个是受激发后而产生的光子。由于光辐射的能量与光子数成正比例,因而在受激辐射以后,光辐射能量增大一倍。null以波动观点看,设外来光子为一种波,受激辐射产生的光子为另一种波,由于两个波的相位、振动方向,传播的方向及频率相同,两个波合在一起能量就增大1倍,即通过受激辐射光波被放大。外来光子量越多,受激发的粒子数越多,产生的光子越大,能量越高。 从上可知,受激辐射及吸收同时存在于光辐射与粒子体系,是在同一整体之中相互对立的两个方面,它们发生的可能性是同等的,这两个方面哪一个占主导地位,取决于粒子在两个能级上的分布。激光就是利用受激辐射实现的,也即在激发态的粒子数尽可能多些。以实现受激辐射。 在受激辐射中怎样把粒子数提高到高能级上呢?总的来说粒子数在能级上的分布有两种:一种是热平衡分布,即粒子体系(同种粒子)在热平衡状态下,各能级上的粒子数遵从玻耳兹曼分布:Ni=N0exp(-Ei/KT),把两能级(E2>E1)上的粒子数相比时可看到N2<N1。热平衡状态下的粒子体系在光辐射作用下,光吸收起主导作用,因此一般情况下观察不到光的放大现象。null要想实现光的放大作用,必须得把热平衡分布倒转过来,就可使粒子数在能级中进行另一种新的分布,即非热平行分布。这种新的分布使高能级上粒子分布的数量大于在低能级上粒子分布的数量,即N2>N1,这时受激辐射的过程大于吸收过程,从而实现光放大,一般常称为粒子反转分布。所谓的“反转”,是对热平衡分布比较而言。处于高能级被反转上去的粒子很不稳定,常会自发在或在外加的刺激下辐射出能量,从高能级粒子跃迁到低能级上,促使粒子体系回到热平衡分布状态。因而可以看出,实现粒子数反转是实现受激辐射的必要条件之一。 粒子数如何实现反转分布,涉及两个方面:一是粒子体系(工作物质)的内结构;二是给工作物质施加外部作用。所讲的工作物质是指在特定条件下能使两个能级间达到非热平衡状态,而实现光放大,不是每一种物质都能做工作物质。粒子体系中有一些粒子的寿命很短暂,只有10-8秒;有一部分寿命相对较长些,寿命较长的粒子数能级叫做亚稳态能级,亚稳态能级主要有铬离子、钕离子、氖原子、二氧化碳分子、氪离子、氩离子等。null有了亚稳态能级,在一段时间内就可实现某一能级与亚稳态能级的粒子数反转。由于热平衡分布中粒子体系处于低能级的粒子数,总是大于处在高能级上的粒子数,当要实现粒子数反转,就得给粒子体系增加一种外界的作用,促使大量低能级上的粒子反转到高能级上,这种过程被叫做激励,或被称为泵浦,尤如把低处的水抽到高处一样。 经大量实践,人们了解并掌握了一些粒子数反转的有效方法。对固体形的工作物质常应用强光照射的办法,即为光激励,这类工作物质常用的有掺铬刚玉、掺钕玻璃等;对气体形的工作物质,常应用放电的办法,常用的有分子气体(如CO2)及原子气体(如He-Ne原子气体);如工作物质为半导体,采用注入大电流方法激励发光,常见的有砷化镓,这类注入大电流的方法被叫做注入式激励法。此外,还可应用化学反应方法(化学激励法)、超音速绝热膨胀法(热激励),电子束甚至用核反应中生成的粒子进行轰击(电子束泵浦、核泵浦)等方法,都能实现粒子数反转分布。null从能量角度看,泵浦过程就是外界提供能量给粒子体系的过程。激光器中激光能量的来源,是由激励装置,其它形式的能量(诸如光、电、化学、热能等)转换而来。null The Laser System The laser is a system that is similar to an electronic oscillator(电子振荡器). An Oscillator is a system that produces oscillations without an external driving mechanism. To demonstrate(示范) an oscillator, we can use the familiar analog(类似物): A sound amplification system has a microphone, amplifier and speaker. When the microphone is placed in front of the speaker, a closed circuit [‘s:kit](回路) is formed, and a whistle [(h)wisl] is heard out of the speaker. The whistle is created spontaneously, without any external source. nullExplanation: The speaker‘s internal noise is detected by the microphone, amplified and the amplified signal is again collected by the microphone. This positive feedback(反馈) continues until a loud whistle is heard. The laser can be described as composed of four structural units: 1. Active medium(激活媒质), which serves as an optical(光学的) amplifier(放大器). 2. Excitation mechanism(激发机制). 3. Optical feedback(光学反馈). 4. Output coupler, to allow electromagnetic radiation out of the laser device.null 激光的产生,必须有激光器,而激光器必须具备三个主要的组成部分。   1.激活物质:即被激励后能发生粒子数反转的工作物质,也称做激光工作物质。诸如氖、氩、CO2、红宝石及钕玻璃等。必须具备有亚稳态能级性质的物质。   2.激励装置:能使激活介质发生粒子数反转分布的能源,既称为激励装置。如各种激光器所具备的电源。   3.光学谐振腔:能使光子在其中重复振荡并多次被放大的一种由硬质玻璃制成的谐振腔。 激光振荡器中工作物质发出的光不是外来的,而是工作物质本身自发跃迁产生的,即自发辐射。由于自发辐射没有确定的频率及传播方向,且杂乱无章,为使自发辐射频率单一性,就需要有一装置来实现,即光学谐振腔。谐振腔即指两块反射镜构成的空间,在工作物质的两侧放置两块反射镜,且反射镜必须彼此平行,并与工作物质的光轴垂直。null  两个反射镜中,一个是全反射镜,反射有效率为99.8%,一个是半反射镜。反射率为40%~60%。在谐振腔中,初始的光辐射是来自自发辐射。自发辐射光子不断产生,同时射向工作物质,再激发工作物质产生很多新光子(受激辐射)。光子在传播中一部分射到反射镜上,另一部分则通过侧面的透明物质跑掉。光在反射镜的作用下又回到工作物质中,再激发高能级上的粒子向低能级跃迁,而产生新的光子。在这些光子中,不再沿谐振腔轴方向运动的光子,就不与腔内的物质作用。沿轴方向运动的光子,经过谐振腔中的两个反射镜多次反射,使受激辐射的强度越来越强。促使高能级上的粒子不断地发出光来。如果光放大到超过光损耗(衍射、吸收、散射等损失)时,就产生光的振荡,使积累在沿轴方向的光,从部分反射镜中射出这就形成激光。在谐振腔的反馈过程中,我们了解到光只能沿谐振腔的轴向传播,因此激光具有很高的方向性。null又由于谐振腔中两个反射镜之间距离不同,光在腔内不断地反射,得到加强。而其它波长的光在腔内很快被衰减掉,谐振腔就可选择一固定波长,说明激光具有单色性。而激光的高亮度是由光放大产生的。产生激光的过程可归纳为:激励→激活介质(即工作物质)粒子数反转;被激励后的工作物质中偶然发出的自发辐射→其它粒子的受激辐射→光子放大→光子振荡及光子放大→激光产生。null 实际应用的激光器种类很多,如以组成激光器的工作物质来说可分为气体激光器、液体激光器、固体激光器、半导体激光器、化学激光器等。同一类型的激光器中又包括许多不同材料的激光器,如固体激光器中有红宝石激光器、钇铝石榴石(Nd:YAG)激光器。气体型的激光器主要有He-Ne(氦-氖)、CO2及氩离子激光器等。由于工作物质不同,产生光波波长不同,因而应用范围也不相同。最常用而范围广的有CO2及钇铝石榴石激光器。有的激光器可连续工作,如He-Ne激光器;有的以脉冲形式发光工作,如红宝石激光;而另一些激光器既可连续工作,又可脉冲工作,有CO2及钇铝石榴石激光器。 Many thousands of kinds of laser are known, but most of them are not used beyond(除…以外) specialised research. This is a list of laser types: Gas lasers, Chemical lasers, Metal-vapor lasers, Solid-state lasers, Semiconductor lasers, Other types of lasers.null氩离子激光器null钇铝石榴石(Nd:YAG)激光器nullApplications of LaserApplications of
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