A Frequency Modulation He-Ne Gas Laser With Stable Output Power Based On Optical Tunneling Effect

Due to its excellent optical quality,He-Ne gas laser are widely used in scientific research,high precision measurement,information transmission and processing,and many other fields.In recent years,frequency modulated laser are needed in some practical applications(such as coherent communication and coherent detection).However,the output power of He-Ne laser varies with the laser frequency.Therefore,it is very necessary to develop a frequency modulation He-Ne laser with stable output power.Compared with the conventional frequency modulation He-Ne laser,the designed He-Ne laser achieves power compensation from optical tunneling effect.So,in the realization of frequency modulation,the stability of output power has been significantly improved.The work done in this paper,is expected to widen the application filed of He-Ne laser,and to improve the performance of optical systems.The main contents are listed as follows:1.The expression of laser output power was derived with considering about the loss caused by optical tunneling effect.Theoretical models and simulation software were used to calculate the loss caused by surface roughness of Brewster window.The formula of deflection of Brewster angle was given to adjust installation of the Brewster window.2.The plan based on optical tunneling effect was discussed to acquire the stability of the laser output power.By changing the optical tunneling distance,the output power has been controlled.The microcrystalline glass was used to make the resonant cavity.Finally,the frequency modulation He-Ne laser with a stable output power was designed and manufactured.3.Based on PID control principle,the LabVIEW language was used to design a feedback control software.And by using this software,the stability of the output power is significantly improved.4.Using scanning confocal spherical interferometer and M2 factor measuring instrument,the frequency characteristics and beam quality of the designed laser were measured.The results show that the laser works in double longitudinal mode,and it has a good beam quality as the value of the M~2 factor is 1.029.