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激光是六十年代初兴起的一门新的科学技术。它的出现,标志着人们对光的控制和利用有了新的飞跃,引起世界各国的重视,在短短十四、五年内,迅速广泛地应用到了许多科学技术领域中。激光具有的特性,为军事技术、生产建设和科学实验的许多方面的发展提供了一系列的途径。激光具有的特性是: 1.很高的方向性。普通光源发出的光是向四面八方均匀地发散的,而激光具有很高的方向性。它是沿着一定方向发光的,光束的发散角很小,一般可达毫弧度(10~(-3)弧度)的数量级,比最好的探照灯的发散角还要小几百倍。 2.很好的单色性。普通光源发出的光,波长分布很宽,如可见光含有从0.40～0.76微米的波长。太阳光的白光在分光镜下可分成红、橙、黄、绿、青、兰、紫七色以及其它的辐射波长,这种光称为非单色光。而激光波长范围很窄,一般小于几个埃(1微米=10~(-4)厘米,1埃=10~(-8)厘米,平时用Α作埃的标记)。所以,激光单色性很好。 3.很好的相干性。在普通光源中,各发光中心是相互独立的,相互之间根本上没有相
Laser is a new science and technology that has emerged in the early 1960s. Its emergence marks a new leap forward in the control and utilization of light, which has drawn the attention of all countries in the world and has been rapidly and extensively applied to many fields of science and technology in just fourteen to five years. The characteristics of lasers offer a range of avenues for the development of many aspects of military technology, manufacturing, and scientific experimentation. Laser has the characteristics are: 1. High directivity. Ordinary light source of light is evenly divergent in all directions, and the laser has a high directivity. It glows in a certain direction and the divergence angle of the beam is small, typically on the order of milliradians (10 to (-3) radian), hundreds of times smaller than the best searchlight divergence angle. 2 very good monochrome. Light emitted by a normal light source has a wide wavelength distribution such as visible light containing wavelengths from 0.40 to 0.76 microns. The white light of the sun can be divided into red, orange, yellow, green, blue, blue, violet, and other wavelengths of radiation under a spectroscope. Such light is called non-monochromatic light. The laser wavelength range is very narrow, generally less than a few angstroms (1 micron = 10 ~ (-4) cm, 1 angstroms = 10 ~ (-8) cm, usually with Α as Egypt mark). Therefore, the laser monochromatic good. 3. Good coherence. In ordinary light sources, the luminescent centers are independent of each other, there is no phase between them