本文介绍了多碱光电阴极的特点及其在微光像增强器中的应用，叙述了光致荧光的原理，探索了利用光致荧光方法来研究多碱阴极Na2KSb膜层电子跃迁几率的方法，并测量了两个不同灵敏度多碱阴极的荧光谱及同一个多碱阴极在工作和非工作两种状态下的荧光谱.测试结果表明，多碱阴极的荧光强度与其电子跃迁的几率及阴极灵敏度成正比，同时多碱阴极在工作状态下，荧光强度比非工作状态下有所降低，原因是一部分跃迁电子逸出多碱阴极产生光电发射，而这部分电子不再回到基态，因此不再发出荧光.另外本文还测量了多碱阴极在不同波长激光激发条件下的荧光谱.结果表明，长波激发与短波激发相比，长波激发所获得的荧光强度更高，这说明长波激发产生跃迁电子的几率高，同时荧光谱峰值波长与激光波长的偏移较小，因此跃迁电子数多且能量损失小，有利于光电发射.将多碱阴极的荧光谱与多碱阴极的量子效率相比较，看出跃迁电子数量和所处能级这两个对光电发射过程有影响的关键因素中，能级因素对光电发射过程的影响更大.但对多碱阴极而言，由于短波激发时的电子跃迁几率低于长波激发时的电子跃迁几率，跃迁电子扩散过程中的能量损失较大，因此短波的量子效率随波长的增加而增加.实践证明，光致荧光是研究多碱阴极光电发射过程的一种有效手段，通过对多碱阴极荧光谱的研究，进一步揭示了多碱阴极的光电发射的机理，为进一步改进工艺和提高多碱阴极的灵敏度提供了重要的参考价值.

The characteristics of multi-alkali photocathode and its application in low light level image intensifier are introduced, the principle of light induced fluorescence is described, the method to study electron transition probability of Na2KSb cathode film by use of light induced fluorescence is explored, and the fluorescence spectrum of two different cathodes in the states of work and non work are measured respectively. The test results show that, the fluorescence intensity of cathode is proportional to both its electronic transition probability and sensitivity, at the same time fluorescence intensity in work states declines compared to that in non work states. The reason is that part of the transition electrons escape from cathode surface and produce photoelectric emission. These transition electrons do not return to the ground state, therefore they do not emit fluorescence no longer. In this paper the fluorescence spectrum of cathode is also measured excited at different wavelengths of incident light. The results show that, compared with short waves excitation, long waves excitation can obtain higher intensity, which shows long waves excitation can get higher transition electron probability as well; at the same time wavelength shifts between fluorescence peak wavelength and excitation light wavelength is smaller; therefore, the energy loss is small, the photoelectric emission is more favorable. Compared the fluorescence spectrum with multi-alkali photocathode quantum efficiency, it can be concluded that transition electron energy level plays more important role in the process of photoelectric emission between transition electron number and the energy level. As to the multi-alkali cathode, due to electron transition probability of short wave excitation is relatively small, and energy loss of the transition electron diffusion process is bigger, therefore the short-wave quantum efficiency decreases as wavelength decreases. Practice has proved that the photoluminescence is an effective study way of cathode photoemission process, through the study of cathode fluorescence spectrum the cathode photoelectric emission mechanism is further revealed. This provides important reference value for further improving the process and raising the cathode sensitivity.