Study On Self-collimation Of Oxygen-iodine Chemical Laser Optical Resonator

In view of the increasing output energy of China's oxygen-iodine chemical lasers and the improvement of the beam quality becomes an urgent need,one of the main factors limiting the beam quality is the misalignment of the optical cavity in the light emission process.In the experiment process for the cavity,the external through-cavity light is needed as the light source.During the experiment,the through-cavity light should pass through the center of the concave cavity mirror and reflect and interfere in the optical resonant cavity,and finally form a concentric circle behind the convex cavity mirror Ring image.Therefore,the experiment must first ensure that the guided light can be collimated into the center of the concave cavity mirror,and secondly make the optical cavity concave-convex cavity mirrors parallel to each other.First,when the light passing through the cavity passes through the cavity,a laser spot is imaged behind the cavity mirror,and the helium-neon penetrating light is collimated and injected by adjusting the device In the cavity,the center coordinates of the laser spot on the image are obtained by image processing methods such as least squares circle fitting.By adjusting the incident angle of the light passing through the cavity by He-Ne,it is found that the center coordinates of the laser spot will change accordingly.The coordinate change is used as the criterion for the self-collimation of the helium-neon laser and the cavity,so obtaining the accurate laser spot center coordinates can be used as the theoretical basis for subsequent auto-collimation experiments.Then we use helium-neon light to pass through the center hole of the concave cavity mirror,and an industrial camera is placed behind the convex cavity mirror to form an interference concentric ring above the screen.Through the image processing methods such as binarization and Kirchhoff circle detection in the Computer Vision Library,the center coordinates of the interference concentric ring are obtained,and the image is divided into four parts:upper,lower,left,and right.The difference between the number of bright dot pixels is used to estimate the offset state of the interference concentric ring,and then the theoretical misalignment criterion for the change of the optical resonator under the cavity condition is obtained.The experimental results show that this method can obtain quite accurate optical resonance cavity misalignment criterion.The misalignment criterion is selected as the pixel difference of left and right bright points of 30000,and the pixel difference of upper and lower bright points of 45,000.Get well prepared.