Study On The Transformation Characteristics Of Gas Laser Mode And Optical System

In order to make the He-Ne laser to better meet the needs of people, we must improve its output power, reduce its volume, so that it can output better quality beams. Only by analyzing the specific mode of the laser can suppress the harmful mode, using the thin lens to focus, collimation, and beam expanding of Gauss beam, we can get the beam which practical application needs. So it is very important to study the mode of gas laser and the transformation of Gauss beam through the optical system.In this paper, the mode of He-Ne laser and the transformation of the optical system are mainly studied from the following aspects:First of all, it introduces the research background, domestic and foreign current situation and basic theory of the He-Ne laser; The laser output characteristics were measured through the experimental method. The cavity length and the relationship between the after mirror curvature radius and laser output characteristics are given; In a certain range, the output power increases with the increase of the cavity length, and decreases with the increase of the radius of curvature.Second is the laser mode analysis. The different curvature radius and light spot and frequency spectrum of different cavity length were measured by laser spot analysis software and the confocal scanning interferometer. The mode of laser is analyzed with the detailed theoretical calculation and the experimental data.The third is to study the transformation process of laser beam through the optical system. Mainly analyzed the propagation rules which the Gaussian beam in free space, optical system, The Q parameters of Gauss beam are leaded into, and the ABCD formula of Gauss beam is given by any optical system, and the transmission problem of Gauss beam is analyzed with Q parameters; An experimental is studied on the transformation of Gauss beam through a thin lens; Through the fitting of the divergence angle of the Gauss beam passing through the thin lens, the results of the experiment and the theory are obtained; Finally, on the basis of the experiment of Gauss beam passing through the thin lens, the laser beam expander is studied by using an inverted telescope, and the combined lens of the best beam expanding effect is given.