Research On Discharge Excitation Of Ring-shaped HeNe Laser

Based on optical Sagnac effect,laser gyro has become the high-precision inertial navigation instrument which is widely used in modern national defense.As the core component of laser gyro,ring he-ne laser achieves population inversion by discharge incentives and commonly used DC and RF incentives.In DC discharge excitation,the electron emission characteristics of cathode materials and cathode oxidation process are the key factors affecting the service life and performance of laser.In RF excitation,RF excitation frequency and structural parameters of laser play a decisive role for laser light.Therefore,researching these questions of ring he-ne laser in different discharge incentives is of great significance.In order to study the cathode electron emission characteristics and the influence of cathode oxidation process on ring he-ne laser,photoelectric retarding field method is used to measure the work function of cathode by using homemade(?)spherical phototube.The experiment measured the work function of commonly used aluminum cathode is 2.60? 2.60 eV,and the work function decreases with the increase of oxidation time of aluminum cathode.The parallel electrode discharge tube which can simulate the discharge process of ring he-ne laser is designed as well and used to study the parameters of gas discharge and the influence of cathode oxidation process on discharge parameters.Experiment results show that ignition voltage and tube voltage drop with the increase of the cathode oxidation time reduced first,then increase and finally decrease.The trends of normal glow discharge of maximum current density is just the opposite.Comprehensive analysis of aluminum cathode optimal oxidation time between 0?30 min,15 min is the best.Volume miniaturization requirement of ring he-ne laser is put forward by practical engineering application.This paper design a RF excitation microminiature annular he-ne laser by analyzing and summarizing predecessors' research experience.The laser cavity parameters and appropriate incentives and incentive frequency is calculated and selected.The rf excitation ring he-ne laser without inner electrodes.Its structural parameters are:discharge tube diameter is 2.5 mm,mirror curvature is 0.5 m,the total cavity length is 4 cm,gain length 0.9 × 4 cm,total pressure is 800 Pa,the ratio is He:Ne=9:1,the size of electrode pad is 20× 5 mm2,electrode spacing is 8 mm.The small annular he-ne laser has the laser output by using 180 MHz and 300 MHz rf pumped.The rusult show that this design scheme is feasible.