Measurement of the Frequency Characteristics of Longitudinal and Transverse Modes in He-Ne Lasers

In order to realize the abstract concept of the longitudinal and transverse laser modes,and carry out the courses and experiment efficiently,the measurement study of the frequency characteristics of the multi-longitudinal and complex transverse modes was investigated in an open cavity He-Ne lasers. From the spectrum of longitudinal modes obtained by the scanning interferometer,the concept and variation of the longitudinal modes can be realized clearly. With the laser spot pattern and spectrum,the standard transverse modes can be distinguished accurately. While for the complex mixing modes,a simple and feasible method was proposed. The computational simulation results agree well with the experiments. The study methods and corresponding conclusions are of great benefit to the teaching of theoretical and experimental courses in the principle of lasers.