Number of Modes in a Gas Laser Cavity气体激光器谐振腔中的模式数
Though a laser is said to be monochromatic and may involve only one atomic transition to produce the laser light, there are nevertheless a number of cavity modes within the width of that spectral line. Under the operating conditions of gas lasers, the Doppler broadening of the spectral line is the main source of linewidth. In terms of angular frequency, the Doppler linewidth is given by 尽管激光被称作单色的,并且可能仅涉及一个原子跃迁来产生激光光,但在这条谱线宽度内仍存在多个谐振腔模式。在气体激光器的工作条件下,谱线的多普勒展宽是 linewidth 的主要来源。在角频率方面,多普勒 linewidth 给出为
![]() Within that linewidth, the number of modes may be obtained from the photon density of states expression. 在该线宽内,模式数可通过光子密度态表达式获得。
![]() Combining these expressions gives a relationship for the number of modes. 将这些表达式结合起来,可以得到模式数的关系。
![]() The number of modes is one of the factors which determines the necessary pumping power to operate the laser. 模式数是决定激光运行所需泵浦功率的一个因素。
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Index Laser concepts Reference Rohlf Sec. 13-5 索引激光概念 参考 Rohlf 第13-5节 | ||
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